hydrogenation and hydroamination reactions using boron ......ii hydrogenation and hydroamination...

Hydrogenation and Hydroamination Reactions Using Boron-Based Frustrated Lewis Pairs

by

Tayseer Mahdi

A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy

Department of Chemistry University of Toronto

copy Copyright by Tayseer Mahdi 2015

ii

Hydrogenation and Hydroamination Reactions Using

Boron-Based Frustrated Lewis Pairs

Tayseer Mahdi

Doctor of Philosophy


2015

Abstract

New main group systems that provide avenues for small molecule activation have been

illustrated using frustrated Lewis pairs (FLPs) ndash combinations of sterically encumbered Lewis

acids and bases which cannot form adducts The research presented herein expands the small

molecule activation and transformation of FLPs using B(C6F5)3

Combination of the aryl amine tBuNHPh and B(C6F5)3 under H2 at room temperature leads to its

heterolytic splitting forming the complex [tBuNH2Ph][HB(C6F5)3] Exposing the salt to elevated

temperatures is found to follow an alternative mechanism resulting in hydrogenation of the N-

bound phenyl ring affording the isolable cyclohexylammonium salt [tBuNH2Cy][HB(C6F5)3]

This finding is extended to include a series of N-phenyl amines in addition to mono- and di-

substituted pyridines quinolines and several other N-heterocycles

The reaction of B(C6F5)3 and H2 with other substrates namely ketones and aldehydes are also

investigated Catalytic hydrogenation of the carbonyl functional group is achieved in an ethereal

solvent to give alcohol products In these cases the borane and ether behave as a FLP to activate

H2 and effect the reduction Similar reductions are also achieved in toluene using B(C6F5)3 in

iii

combination with cyclodextrins or molecular sieves Reductive deoxygenation occurs in the

particular case of aryl ketones

Finally the Lewis acid B(C6F5)3 is found to enable the intermolecular hydroamination of various

terminal alkynes giving iminium alkynylborate complexes of the general formula

[RPhN=C(CH3)R1][R1CequivCB(C6F5)3] The three-component reaction can also be performed

catalytically generating enamine products which are amenable to subsequent hydrogenation

reactions giving their corresponding amines The chemistry is expanded to intramolecular

systems forming N-heterocyclic compounds Furthermore a FLP route to stoichiometric

hydrophosphination of alkynes is developed

iv

Acknowledgments

Graduate school is not a journey taken alone rather it is one travelled with companions I have a

large group of wonderful people to thank for travelling by my side continuously supporting me

and putting a smile on my face

First and foremost I would like to take this opportunity to express my sincere gratitude to my

supervisor Prof Doug Stephan Thank you for your support you were always positive and open

to discussions Aside from developing my knowledge in chemistry you provided me with the

opportunity to build relationships and grow professionally I have also had the honour of having

very helpful committee members over the past few years Profs Bob Morris and Datong Song I

would like to thank you for your guidance and feedback through the seminar series and

committee meetings Prof Andrew Ashley I truly appreciate the time you took to provide me

with feedback for this thesis and attend my examination Thank you to Prof Erker at the

University of Muumlnster for accepting me to do an exchange in his research group

Of course the results in this thesis would not be publishable without the hard work of the staff at

the University of Toronto I would like to thank you all especially Darcy Burns Dmitry

Pichugin Rose Balazs and Matthew Forbes Also I would like to thank Chris Caputo Peter

Mirtchev Conor Prankevicius Alex Pulis and Adam Ruddy for your time in editing this thesis

All of the past and present Stephan group members thank you for the great times and of course

for doing your lab jobs and keeping the lab functional I definitely have to thank you Shanna for

keeping us in check

I want to give a big shout out to all my Athletic Centre gym buddies rock-climbing fellows

Chem Club soccer team champions and amazing Argon crossfitters I cannot express how much I

enjoyed every moment spent doing these outside-the-lab activities

A big I love you to my most amazing siblings Maithem Christina Jacob and Hoda I do not have

enough room here to express how much you guys mean to me but through it all we have stuck

together and this is how we will continue until the end To my future baby niece you have put a

smile on my face even while you are still inside the womb I cannot wait to meet you Finally to

the most supportive and kind-hearted person I have ever met Renan you have been there for me

from the start of this journey until the end Thank you all

v

Table of Contents

Abstract ii

Acknowledgments iv

Table of Contents v

List of Figures xi

List of Schemes xiv

List of Tables xix

List of Symbols and Abbreviations xxi

Chapter 1 Introduction 1

11 Science and Technology 1

111 Boron properties production and uses 2

112 Boron chemistry 3

12 Catalysis 4

13 Frustrated Lewis Pairs 5

131 Early discovery 5

132 Hydrogen activation and mechanism 6

133 Substrate hydrogenation 9

134 Activation of other small molecules 10

1341 Unsaturated hydrocarbons 10

1342 Alkenes 11

1343 Alkynes 11

1344 11-Carboboration 12

1345 CO2 and SO2 13

1346 FLP activation of carbonyl bonds 14

1347 Carbonyl hydrogenation 15

vi

1348 Carbonyl hydrosilylation 16

14 Scope of Thesis 17

Chapter 2 Metal-Free Aromatic Hydrogenation of N-Phenyl Amines and N-Heterocyclic Compounds 19

21 Introduction 19

211 Hydrogenation 19

212 Transfer hydrogenation 20

213 Main group catalysts 21

214 Hydrogenation of aromatic and heteroaromatic substrates 22

2141 Transition metal catalysts 22

2142 Metal-free catalysts 23

215 Reactivity of FLPs with H2 23

22 Results and Discussion 24

221 H2 activation by amineborane FLPs 24

222 Aromatic hydrogenation of N-phenyl amines 25

2221 Attempts at catalytic aromatic hydrogenation and hydrogenation of other aromatic substrates 30

223 Mechanistic studies for aromatic hydrogenation reactions 31

2231 Deuterium studies 31

2232 Variable temperature NMR studies 32

2233 Theoretical calculations 33

224 Aromatic hydrogenation of substituted N-bound phenyl rings 35

2241 Fluoro-substituted rings and C-F bond transformations 35

2242 Methoxy-substituted rings and C-O bond transformations 38

22421 Mechanistic studies for C-O and B-O bond cleavage 40

225 Aromatic hydrogenation of N-heterocyclic compounds 45

vii

2251 Hydrogenation of substituted pyridines 45

2252 Hydrogenation of substituted N-heterocycles 49

2253 Proposed mechanism for aromatic hydrogenation 55

2254 Approaches to dehydrogenation 55

23 Conclusions 56

24 Experimental Section 56

241 General considerations 56

242 Synthesis of compounds 57

243 X-Ray Crystallography 79

2431 X-Ray data collection and reduction 79

2432 X-Ray data solution and refinement 79

2433 Selected crystallographic data 81

Chapter 3 Enabling Catalytic Ketone and Aldehyde Hydrogenation with Frustrated Lewis Pairs 88

31 Introduction 88

311 FLP reactivity with unsaturated C-O bonds 88


321 B(C6F5)3 decomposition pathway in C=O hydrogenation reactions 92

322 B(C6F5)3 catalyzed carbonyl hydrogenation in ethereal solvents 93

323 Proposed mechanism for the catalytic hydrogenation of ketones using B(C6F5)3 in ethereal solvents 96

324 Structural analogue of the proposed intermediate in the ketone hydrogenation mechanism 97

325 Other hydrogen-bond acceptors for carbonyl hydrogenations 99

326 Other boron-based catalysts for carbonyl hydrogenations 99

327 Alternative approach to catalytic ketone hydrogenation using a B(C6F5)3-assisted mechanism 100

viii

3271 Proposed mechanism for ketone hydrogenation using the B(C6F5)3[NEt4][HB(C6F5)3] catalyst system 102

328 Attempted hydrogenation of other carbonyl substrates and epoxides 102

329 FLPs comprised of B(C6F5)3 with polysaccharides or molecular sieves as Lewis bases 103

3291 Polysaccharides as heterogeneous Lewis bases 104

3292 Molecular sieves as heterogeneous Lewis bases 107

3293 Reductive deoxygenation of alkyl aryl ketones and diaryl ketones 107

3210 Proposed mechanism for catalytic carbonyl hydrogenation and reductive deoxygenation 110

32101 Verifying the reductive deoxygenation mechanism 111

3211 Other heterogeneous Lewis bases and attempting the hydrogenation of olefins 113

33 Conclusions 113


341 General Considerations 114

342 Synthesis of Compounds 116

3421 Procedures for reactions in ethereal solvents 116

3422 Procedures for reactions using B(C6F5)3 and [NEt4][HB(C6F5)3] 119

3423 Procedures for reactions using heterogeneous Lewis bases 120

3424 Procedures for reductive deoxygenation reactions 121

3425 Spectroscopic data of products in Table 31 121



3428 Spectroscopic data of products in Table 34 and Scheme 312 (a) 127

3429 Spectroscopic data of products in Table 35 and Scheme 312 (b) 128



ix



Chapter 4 Hydroamination and Hydrophosphination Reactions Using Frustrated Lewis Pairs 132

41 Introduction 132

411 Hydroamination 132

412 Reactions of main group FLPs with alkynes 133

4121 12-Addition or deprotonation reactions 133

4122 11-Carboboration reactions 134

4123 Hydroelementation reactions 135

413 Reactions of transition metal FLPs with alkynes 135


421 Stoichiometric intermolecular hydroamination and deprotonation of terminal alkynes 136

4211 Proposed mechanism for the hydroamination and deprotonation reactions of terminal alkynes 140

4212 Reactivity of amineborane FLPs with internal alkynes and other unsaturated substrates 141

4213 Reactivity of the iminium alkynylborate products with nucleophiles 141

422 Friedel-Crafts hydroarylation of phenylacetylene using aromatic amines and B(C6F5)3 142

423 B(C6F5)3 catalyzed intermolecular hydroamination of terminal alkynes 144

4231 Proposed mechanism for B(C6F5)3 catalyzed intermolecular hydroamination reactions 146

4232 One-pot catalytic hydroamination and hydrogenation reactions of terminal alkynes 147

424 Intramolecular hydroamination reactions using FLPs 148

4241 Stoichiometric hydroamination 148

4242 B(C6F5)3 catalyzed intramolecular hydroamination to generate cyclized amines 150

x

425 Reaction of B(C6F5)3 with ethynylphosphines 151

4251 Proposed mechanism for reaction of B(C6F5)3 and ethynylphosphines 153

426 Stoichiometric hydrophosphination of acetylenic groups using FLPs 154

427 Proposed mechanism for the hydroborationhydrophosphination reactions 156

43 Conclusions 157




4421 Procedures for stoichiometric intermolecular hydroamination reactions 158

4422 Procedures for hydroarylation of phenylacetylene 165

4423 Procedures for catalytic intermolecular hydroamination reactions 167

4424 Procedures for tandem hydroamination and hydrogenation reactions 172

4425 Procedures for stoichiometric and catalytic intramolecular hydroamination reactions 173

4426 Procedures for reactions with ethynylphosphines 177




4433 Platon Squeeze details 180


Chapter 5 Conclusion 185

51 Thesis Summary 185

52 Future Work 186

References 189

xi

List of Figures

Figure 11 ndash Proposed tBu3PB(C6F5)3 encounter complex with electron transfer (a) and electric

field (b) models representing H2 cleavage 8

Figure 12 ndash A highly efficient borenium hydrogenation catalyst 10

Figure 21 ndash An amine(imine)diphosphine iron complex (a) and an electrophilic phosphonium

cation (b) used for transfer hydrogenation catalysis 21

Figure 22 ndash Allylcobalt (left) and TaV and NbV hydride (right) catalysts used for the

homogeneous hydrogenation of aromatic substrates 23

Figure 23 ndash POV-Ray depiction of 24rsquo 26

Figure 24 ndash 1H NMR (400 MHz CD2Cl2) spectrum with insets in specified regions showing the

partially hydrogenated cation [3-(C6H9)NH2iPr]+ 27

Figure 25 ndash High temperature 1H NMR (400 MHz C6D5Br 383 K) stack plot depicting

iPrNHPh consumption to form 24 iPr methine for iPrNHPh () and [iPrNH2Cy]+ ($) 27

Figure 26 ndash POV-Ray drawings of 24 (left) and 25 (right) 28

Figure 27 ndash 2H NMR (615 MHz C6H5Br) stack plot representing reversible D2 activation

releasing HD at 110 degC (left) Corresponding 1H NMR (400 MHz C6H5Br) stack plot showing

activation of HD and formation of [HB(C6F5)3]- at 110 degC (right) 31

Figure 28 ndash Variable temperature 11B NMR (128 MHz C6D5Br) stack plot of 24rsquo under H2

showing dissociation of B(C6F5)3 with increase in temperature (11B δ 53 ppm B(C6F5)3 -25

ppm [HB(C6F5)3]-) 33

Figure 29 ndash Proposed mechanism for aromatic hydrogenations based on quantum chemical

calculations Optimized structure energies are in parentheses and free enthalpies ΔG (298 K) are

relative to FLP + H2 (all data are in kcalmol) 34

Figure 210 ndash POV-Ray drawing of 216a 36

xii

Figure 211 ndash POV-Ray drawing of 218 37


Figure 213 ndash POV-Ray drawing of trans-220 40

Figure 214 ndash 1H NMR stack plot (d8-tol) of CH3OH isolated from independent synthesis of 219

(a) CH3OH isolated from synthesis of 223 starting from p-CH3OC6H4NHiPr (b) CH3OH in d8-

tol (c) 42


Figure 216 ndash POV-Ray drawing of 224 (left) and 225 (right) 46

Figure 217 ndash POV-Ray depiction of 227a B-N 1662(2) Aring 48

Figure 218 ndash 2-Dimensional 1H19F HOESY NMR (400377 MHz C6D5Br) spectrum showing

cross peaks between Ph-piperidine (1H δ 415 CH 555 NH 720 Ph) and o-C6F5 groups 49

Figure 219 ndash 1234-Tetrahydroquinoline with emphasis on the fused carbocyclic ring 49

Figure 220 ndash POV-Ray depiction of the cations for compounds 228 (a) 229 (b) and 230 (c) 50

Figure 221 ndash POV-Ray depiction of the cation for compound 231a 51

Figure 222 ndash POV-Ray depiction of 231b B-N 1666(2) Aring 52

Figure 223 ndash POV-Ray depiction of the cation for compound 233 52

Figure 224 ndash POV-Ray depiction of the cations for compounds 234a (left) and 234b (right) 53

Figure 225 ndash POV-Ray depiction of the cation for compound 235 Selected bond distances (Aring)

and angles (deg) B(1)-N(1) 1615(3) B(1)-N(2) 1598(3) N(1)-B(1)-N(2) 9663(19) N(1) amine

N(2) pyridine 54

Figure 31 ndash 1H NMR (600 MHz d8-tol 343 K) stack plot showing catalytic hydrogenation of 4-

heptanone resulting in gradual formation of 4-heptanol Acquisitions are obtained over 1 h time

intervals Starting material 4-heptanone ($) product 4-heptanol () 94

xiii

Figure 32 ndash Plot representing the dependence of Et2O equivalents on the conversion of 4-

heptanone to 4-heptanol 95

Figure 33 ndash POV-Ray depiction of 31 98

Figure 34 ndash Borenium cation-based FLP hydrogenation catalysts tested in ketone hydrogenation

reactions [B(C6F5)4]- anions have been omitted 100

Figure 35 ndash Chemical structure of aluminosilicate framework of α-cyclodextrin (a) and MS (b)

104

Figure 36 ndash 1H NMR (400 MHz d8-tol) stack plot showing HD (a) isotope equilibration by 5

mol B(C6F5)3 and α-CD after 12 h at 60 degC (b) 1H δ 456 (H2) 452 1JHD = 423 Hz (HD) 104

Figure 37 ndash 1H NMR (500 MHz d8-tol) stack plot showing consumption of diphenylmethanol

(530 ppm) and formation of diphenylmethane (372 ppm) as the equivalents of benzophenone

(749 and 722 ppm) is gradually increased 112

Figure 41 ndash POV-Ray depiction of 41 N=C 1308(2) Aring sum of bond angles at nitrogen 3599deg

136


Figure 43 ndash POV-Ray depiction of Z-48 (a) and Z-49 (b) 139


Figure 45 ndash POV-Ray depiction of 413 (a) and 414 (b) Compound 414 N=Canthracene bond

length 1305(5)Aring bond angle iPrC-N=Canthracene 1328deg 143


Figure 47 ndash 1H (top) and 1H31P (bottom) NMR (400 MHz CD2Cl2) stack plot of compound

439 with insets focusing on the vinylic protons 152

Figure 48 ndash POV-Ray depictions of 439 (a) and 440 (b) 153

Figure 49 ndash POV-Ray depictions of 442 155

xiv

List of Schemes

Scheme 11 ndash Dimethyl zirconocene catalyst activation with B(C6F5)3 4

Scheme 12 ndash Hydroboration of terminal alkynes to give alkenylboranes followed by cross-

coupling with an alkyl or aryl halide (M = Cu Pd Ni or Fe) 4

Scheme 13 ndash Reversible H2 activation by linked phosphine-borane FLP 6

Scheme 14 ndash Heterolytic H2 activation by an intramolecular PB FLP (a) reversible H2

activation by an NB FLP (b) and H2 activation by an intermolecular PB FLP (c) 7

Scheme 15 ndash Schematic representation of equilibrium formation of the boraindene-Et3SiH

adduct at 195 K 9

Scheme 16 ndash Proposed mechanism for B(C6F5)3 catalyzed reduction of imines 9

Scheme 17 ndash Intermolecular addition of frustrated tBu3PB(C6F5)3 pairs to olefins (top)

equilibrium between ldquoopenrdquo and ldquoclosedrdquo form of a tethered olefin-borane species (bottom) 11

Scheme 18 ndash Reaction of FLPs with phenylacetylene 12

Scheme 19 ndash 11-Carboboration reaction of terminal (top) and internal alkynes (bottom) 12

Scheme 110 ndash Proposed reaction mechanism of B(C6F5)3 with terminal alkynes in the presence

(right) and absence (left) of a Lewis base 13

Scheme 111 ndashActivation of CO2 and SO2 using intermolecular (a) and intramolecular (b) PB

FLPs activation of CO2 using PAl FLP (c) (R = H Me E = C S X = Br I) 14

Scheme 112 ndash Stoichiometric reaction of benzaldehyde with the linked PB (top) and NB

(bottom) FLPs 15

Scheme 113 ndash Stoichiometric reaction of benzaldehyde with the linked phosphonium

borohydride FLP 16

xv

Scheme 114 ndash B(C6F5)3 catalyzed hydrosilylation of aromatic aldehydes ketones and esters

using Ph3SiH (top) stereochemical analysis of the hydrosilylation mechanism (bottom) 17

Scheme 21 ndash Transition metal hydrogenation catalysts Wilkinson (a) Noyori (b) Crabtree (c)

and Chirik (d) py = pyridine 20

Scheme 22 ndash H2 activation by 26-lutidine and B(C6F5)3 (a) partial hydrogenation of substituted

quinoline to 1234-tetrahydroquinoline (b) 24

Scheme 23 ndash Reactions of B(C6F5)3 and H2 with tBuNHPh and 14-C6H4(CH2NHtBu)2 at 25 degC

to make 21 (top) and 22 (bottom) 25

Scheme 24 ndash Aromatic hydrogenation of tBuNHPh to give 23 26

Scheme 25 ndash Reversible D2 activation by tBuNHPh and B(C6F5)3 to give HD 32

Scheme 26 ndash Aromatic hydrogenation of 21 to give 23 32

Scheme 27 ndash Proposed reaction pathway to anilinium and cyclohexylammonium salts 35

Scheme 28 ndash Arene hydrogenation of (2-FPh)NHiPr (a) and (3-FPh)NHiPr (b) to give 216a 36

Scheme 29 ndash Arene hydrogenation of (4-FPh)NHiPr to give 218 37

Scheme 210 ndash Reaction of (p-CH3OC6H4)N=CCH3Ph and B(C6F5)3 with H2 to give 219 39

Scheme 211 ndash Synthesis of 220 and 212 40

Scheme 212 ndash Thermolysis reactions of trans-[(4-CH3OC6H10)NH2CH(CH3)Ph][XB(C6F5)3] (X

= C6F5 221a and X = H 221b) 41

Scheme 213 ndash Thermolysis of trans-(4-CH3OC6H10)NHiPr and B(C6F5)3 43

Scheme 214 ndash H2 activation between [CH3OB(C6F5)3]- anion and B(C6F5)3 44

Scheme 215 ndash Overall proposed mechanism for the formation of 7-azabicyclo[221] heptane 45

Scheme 216 ndash Proposed reaction pathway for the formation of 235 54

xvi

Scheme 31 ndash Reaction of Mes2PCH2CH2B(C6F5)2 with benzaldehyde and trans-cinnamaldehyde

(top) stoichiometric reduction of benzaldehyde using Mes2P(H)CH2CH2BH(C6F5)2 (bottom) 89

Scheme 32 minus Stoichiometric reduction of aryl ketones to aromatic hydrocarbons (a) and alkyl

ketones to borinic esters (b) 90

Scheme 33 ndash Asymmetric hydrogenation of silyl enol ethers to yield optically active secondary

alcohols 90

Scheme 34 ndash Reaction of cyclopentenylphosphine with HB(C6F5)2 and carbon monoxide (top)

reaction of tBu3P and B(C6F5)3 with COH2 to generate (C6F5)2BCH(C6F5)OB(C6F5)3 (bottom) 91

Scheme 35 ndash Activation of H2 by amineborane FLP while in the presence of CH3OH 92

Scheme 36 ndash Two pathways proposed in the decomposition of B(C6F5)3 during ketone

hydrogenation 93

Scheme 37 ndash Proposed mechanism for catalytic ketone hydrogenation in ethereal solvents 97

Scheme 38 ndash Synthesis of 31 98

Scheme 39 ndash Example demonstrating lability of a B(C6F5)3-alkoxide bond 100

Scheme 310 ndash Proposed mechanism for B(C6F5)3[NEt4][HB(C6F5)3] catalyst system used in

ketone hydrogenation 102

Scheme 311 ndash Catalytic hydrogenation and reductive deoxygenation of acetophenone 108

Scheme 312 ndash Hydrogenation and deoxygenation of 1-tetralone (a) and dibenzosuberone (b) 110

Scheme 313 ndash Proposed mechanism for hydrogenation of carbonyl substrates and reductive

deoxygenation of aryl ketones 111

Scheme 41 ndash Reaction of sterically hindered tertiary phosphines and E(C6F5)3 with

phenylacetylene to give 12-addition or deprotonation products (E = B or Al) 133

xvii

Scheme 42 ndash FLP-type 12-addition reactions of B(C6F5)3 to pendant alkyne substituted anilines

(a) and N-heterocycles (b) 12-addition of ethylene-linked sulphurborane FLP to

phenylacetylene generating SB alkenyl-FLPs (c) 134

Scheme 43 ndash 11-Carboboration of terminal and internal alkynes to generate a series of

alkenylboranes 134

Scheme 44 ndash B(C6F5)3 catalyzed hydrostannylation (a) and hydrogermylation (b) of alkynes 135

Scheme 45 ndash Reaction of zirconocene phosphinoaryloxide complexes with terminal alkynes 135

Scheme 46 ndash Stoichiometric hydroamination and deprotonation of phenylacetylene yielding 41

136

Scheme 47 ndash Proposed mechanism for the hydroamination and deprotonation reactions

generating iminium alkynylborate salts 140

Scheme 48 ndash Deprotonation of phenylacetylene by diisopropylamine and B(C6F5)3 141

Scheme 49 ndash Deprotonation of 42-cation by fluoride sources and regeneration of the cation

with [(Et2O)2H][B(C6F5)4] 141

Scheme 410 ndash Reaction of 42-cation with organolithium sources (left) and LiAlH4 (right) 142

Scheme 411 ndash Hydroarylation of phenylacetylene using stoichiometric equivalents of

dibenzylaniline and B(C6F5)3 142

Scheme 412 ndash Treatment of compound 413 with protic salts [(Et2O)2H][B(C6F5)4] or

[Ph2NH2][B(C6F5)4] to cleave the B-C bond 144

Scheme 413 ndash Proposed mechanism for catalytic intermolecular hydroamination of terminal

alkynes 147

Scheme 414 ndash One-pot stepwise catalytic hydroamination and hydrogenation reactions giving

429 and 430 148

xviii

Scheme 415 ndash B(C6F5)3-mediated intramolecular cyclization of alkynyl-substituted anilines to

generate 431 and 432 149

Scheme 416 ndash Successive hydroamination and hydrogenation reactions of

C6H5NHCH2(C6H4)CequivCH and B(C6F5)3 to generate 433 150

Scheme 417 ndash Catalytic intramolecular hydroamination and hydrogenation of

C6H5NHCH2(C6H4)CequivCH 151

Scheme 418 ndash Reaction of iPrNHPhB(C6F5)3 with two equivalents of Mes2PCequivCH generating

the zwitterion 439 152

Scheme 419 ndash Proposed mechanism for the 12 combination of B(C6F5)3 and R2PCequivCH to

generate the vinylic zwitterions 439 and 440 154

Scheme 420 ndash Sequential hydroboration and hydrophosphination reactions of hexynyl-

substituted Bpin (a) and 2-methyl-1-buten-3-yne-substituted Bpin (b) using HB(C6F5)2 and

Ph2PH 155

Scheme 421 ndash Proposed reaction mechanism for the hydroboration and hydrophosphination

reactions of Bpin substrates consisting of acetylenic fragments 156

Scheme 51 ndash Chiral borane catalyzed hydrogenation of N-phenyl bound amines with

substitution on the phenyl ring to generate enantiopure substituted cyclohexylamine derivatives

187

Scheme 52 ndash Proposed heterogeneous FLP catalyst for catalytic carbonyl hydrogenations 188

xix

List of Tables

Table 21 ndash Aromatic reduction of N-phenyl amine substrates to N-cyclohexylammonium salts 29

Table 22 ndash Hydrogenation of substituted pyridines 47

Table 23 ndash Hydrogenation of substituted N-heterocycles 51

Table 24 ndash Selected crystallographic data for 24 24rsquo and 25 81

Table 25 ndash Selected crystallographic data for 216a 218 and 219 82

Table 26 ndash Selected crystallographic data for 220 222 and 224 83


Table 28 ndash Selected crystallographic data for 229 230 and 231a 85

Table 29 ndash Selected crystallographic data for 231b 233 and 234a 86

Table 210 ndash Selected crystallographic data for 234b and 235 87

Table 31 ndash Catalytic hydrogenation of ketones and aldehydes in ethereal solvents 96

Table 32 ndash FLP mediated catalytic ketone hydrogenation using B(C6F5)3[NEt4][HB(C6F5)3] 101

Table 33 ndash Catalytic hydrogenation of ketones and aldehydes using heterogeneous Lewis bases

106

Table 34 ndash Deoxygenation of aryl alkyl ketones 108

Table 35 ndash Deoxygenation of diaryl ketones 109

Table 36 ndash Selected crystallographic data for 31 131

Table 41 ndash Stoichiometric intermolecular hydroamination and deprotonation of terminal alkynes

138

Table 42 ndash Intermolecular hydroamination reactions catalyzed by B(C6F5)3 145

xx

Table 43 ndash Catalytic intramolecular hydroamination and hydrogenation of alkynyl-substituted

anilines generating cyclized amines 151




Table 47 ndash Selected crystallographic data for 440 and 442 184

xxi

List of Symbols and Abbreviations

9-BBN 9-borabicyclo[331]nonane

α alpha

Aring angstrom 10-10 m

atm atmosphere

β beta

Bpin pinacolborane (4455-tetramethyl-132-dioxaborolane)

br broad

Boc tert-butyloxycarbonyl

Bu butyl

C Celsius

ca circa

calcd calculated

CD cyclodextrin

C6D6 deuterated benzene

C6H5Br bromobenzene

C6D5Br deuterated bromobenzene

CD2Cl2 deuterated dichloromethane

Cy cyclohexyl

δ chemical shift

xxii

deg degrees

d doublet

Da Dalton

DART direct analysis in real time

DEPT Distortionless Enhancement by Polarization Transfer

dd doublet of doublets

de diastereomeric excess

DFT density functional theory

dt doublet of triplets

ee enantiomeric excess

eq equivalent(s)

ESI electrospray ionization

Et ethyl

Et2O diethyl ether

FLP frustrated Lewis pair

γ gamma

ΔG Gibbs free energy

g gram

GC gas chromatography

GOF goodness of fit

xxiii

h hour

HRMS high resolution mass spectroscopy

HMBC heteronuclear multiple bond correlation

HOESY heteronuclear Overhauser effect NMR spectroscopy

HSQC heteronuclear single quantum correlation

Hz Hertz

iPr2O diisopropyl ether

nJxy n-scalar coupling constant between X and Y atoms

K Kelvin

kcal kilocalories

m meta

m multiplet

M molar concentration

Me methyl

Mes mesityl 246-trimethylphenyl

MHz megahertz

μL microliter

μmol micromole

mg milligram

min minute

xxiv

mL milliliter

mmol millimole

MS mass spectroscopy

MS molecular sieves

nPr n-propyl

iPr iso-propyl (CH(CH3)2)

NHC N-heterocyclic carbene

NMR Nuclear Magnetic Resonance

NOE Nuclear Overhauser Effect

o ortho

π pi

p para

POV-Ray Persistence of Vision Raytracer

PGM Platinum Group Metals

Ph phenyl

Ph2O diphenyl ether

ppb parts per billion 10-9

ppm parts per million 10-6

q quartet

quint quintet

xxv

rpm rotations per minute

RT room temperature

σ sigma

s singlet

t triplet

tBu tert-butyl

THF tetrahydrofuran

TMP 2266-tetramethylpiperidine

TMS trimethylsilyl

TMS2O hexamethyldisiloxane

tol toluene

wt weight

1

Chapter 1 Introduction

11 Science and Technology

The advent of the scientific revolution and the scientific method in early modern Europe

dramatically transformed the way scientists viewed the universe as they attempted to explain the

physical world through experimental investigation The long-term effects of the revolution can

be felt today with our dependence upon science to improve the quality of our lives and advance a

globally interconnected world Some scientific discoveries which have paved the way for such

enterprising technologies include the Haber-Bosch process used for the production of ammonia

essential to the synthesis of nitrogen fertilizers1-3 This discovery has dramatically increased food

production globally and allowed for the explosive population growth observed in the past

century Research also intensified to change the world of medicine through discovery of antiviral

agents for treatment of the HIVAIDS pandemic4-5 Ziegler-Natta catalysts have become central

to the polymer industry manufacturing the largest volumes of commodity plastics and

chemicals6-8

While many chemical breakthroughs have had significant benefits on public health their initial

application or even long-term impact on the environment may be detrimental For example

chlorine was used as a weapon during World War I9 while today it plays a vital role in

disinfecting drinking water and sanitation processes10 A more significant example is the

industrial revolution when manufacturing transitioned from manual labour to machines resulting

in unprecedented growth in population and standards of living Our continued reliance on

factories and mass production has led to depletion of natural resources and emission of

greenhouse gases resulting in anthropogenic climate change11-15

Scientists have acknowledged the need to remediate environmental impacts and to find more

environmentally acceptable technologies for the chemical industry To this end chemical

research has focused on implementing the principles of green chemistry16-17 to develop benign

processes which will sustain the growing energy demands of our society18-19 Central to the green

concept is the application of catalysis in chemical transformations in addition to using readily

available non-toxic raw materials in cost effective procedures

2

Rare precious metals such as the Platinum Group Metals (PGM) are extracted by mining of non-

renewable resources normally resulting in negative social and environmental impacts on the

area20 The metals are used in industrial chemical syntheses where they are regularly recovered

and recycled back into production It is essential however to gradually replace these reagents

with more environmentally benign and readily available transition metals in order to reduce

waste processing costs and eliminate the possibility of their release into the environment In this

aspect chemists are actively seeking innovations to advance more green chemical processes21-24

A vast majority of d-block transition metals have energetically accessible valence d-orbitals

allowing for oxidation state changes which are pivotal to substrate activation and accessing

stabilized transition states Additional factors including the steric and electronic tunability of the

ligand framework have led to the development of a broad range of metal catalysts applied in

numerous chemical transformations25-26 Nonetheless a growing number of advancements

involving the use of main group s and p-block elements have also shown reactivities similar to

those of transition metal complexes27-30

Main group elements are relatively abundant on Earth and over the last decade have experienced

a renaissance in chemical transformations Notably frustrated Lewis pair (FLP) systems which

involve the combination of Lewis acids and bases that are sterically and electronically prohibited

from forming a classical adduct have been at the forefront31 The unquenched reactivity of FLPs

has been explored in the activation of numerous small molecules The majority of FLP systems

incorporate boron Lewis acids and phosphorus Lewis bases32 In this thesis the potential to

expand FLP reactivity to nitrogenboron and oxygenboron pairs is explored

111 Boron properties production and uses

Boron (B) is a non-metallic element always found in nature bound to oxygen as orthoboric acid

alkali metal and alkaline earth metal borates33 Prominent sources of boron include the sodium

borate minerals rasorite and kernite found in deposits at the Mojave Desert of California and in

Turkey which is the largest producer of boron minerals33-34 Boron is vastly spread in Nature

however it constitutes only about 3 ppm of the Earthrsquos crust35-36

Industrially the production of pure boron is very difficult as it tends to form refractory materials

containing small amounts of carbon and other elements The method typically used for

3

commercial production of amorphous boron (up to 97 purity) is by reduction of B2O3 with Mg

in a thermite-like reaction Higher purity (gt99) boron is obtained by the reduction of boron

halides with H2 whereas ultra-purity can be achieved by thermal decomposition of boron

halideshydrides or diboranes on tungsten wires followed by zone melting purification37

Regardless of the production method different allotropic forms of boron can be accessed Short

reaction times at temperatures below 900 degC produce amorphous boron longer reaction times

above 1400 degC afford β-rhombohedral and optimal conditions in between the two give α-

rhombohedral36

Amorphous boron consisting of 90 - 92 purity costs approximately $100kg Relatively large

quantities of the material are used as additives in pyrotechnic mixtures Ultrapure (gt9999)

boron costs about $3500kg and is applied in electronics such as a dopant for germanium and

silicon p-type semiconductors Furthermore as the second hardest element inferior only to

diamond there is a growing demand for boron as a light-weight hardenability additive for glass

ceramics and boron filaments used in high-strength materials for the aerospace and steel

industries35-36

112 Boron chemistry

Boron has a valence shell electron configuration of 2s22p1 representing a typical formal

oxidation state of 3+ although due to its high ionization potentials simple B3+ ions do not exist

Boron can form three sp2 hybridized bonds resulting in trigonal planar geometry with a non-

bonding vacant p-orbital orthogonal to the plane susceptible towards electron donation giving

rise to its noted Lewis acidic properties38-40 Scales to quantify Lewis acidity have been designed

by studying the acceptor-donor interactions between Lewis acid and base complexes using NMR

spectroscopy data based on the Gutmann-Beckett41 and Childs42 methods43 IR spectroscopy X-

ray diffraction44 and density functional calculations45

The most common use of Lewis acids are the boron trihalides particularly BF3 and BCl3 in

conjunction with a co-initiator Lewis base such as water initiating cationic polymerization The

unsaturated olefin monomer is protonated generating the [BF3OH]- counterion along with a

carbenium ion which reacts with olefin molecules leading to propagation of the polymer46 With

Lewis acidity comparable to BF3 the Lewis acid B(C6F5)3 was lsquorediscoveredrsquo in the 1990s as an

ideal activator component for Ziegler-Natta olefin polymerization catalysts47 Treatment of a

4

Group 4 dialkyl-metallocene catalyst precursor with one equivalent of B(C6F5)3 results in alkyl

anion abstraction forming the active alkyl-metallocene cation (eg [Cp2ZrMe]+) stabilized by the

weakly coordinating [MeB(C6F5)3]- anion (Scheme 11)48-51

Scheme 11 ndash Dimethyl zirconocene catalyst activation with B(C6F5)3

Hydroboration the addition of B-H across multiple bonds of organic substrates such as alkenes

and alkynes provides the most common route to alkyl or alkenyl organoborane reagents

respectively52 The products obtained can be employed as intermediates for further synthetic

derivatization One powerful and general methodology used for the modification of

organoboranes53 is the Suzuki-Miyaura cross-coupling reaction (Scheme 12) These C(sp2)-B

and C(sp3)-B organoboranes readily undergo transmetalation with an electrophilic organo- Cu

Pd Ni or Fe catalyst to give coupled products with new C-C bonds54-55 Other applications of

boron reagents include metal borohydrides as reducing agents transferring hydride nucleophiles

to versatile functional groups56-59 Operating in a similar manner anionic borates consisting of

polarized B-C bonds transfer an organic group to an electrophilic centre38 60


coupling with an alkyl or aryl halide (M = Cu Pd Ni or Fe)

Of particular relevance to this thesis recent advances in boron chemistry particularly involving

the activation and reactivity of small molecules with FLP systems will be discussed

12 Catalysis

In the early part of the 20th century catalysis developed into a scientific discipline and has

evolved to underlie numerous chemical technologies that benefit human life worldwide61 The

5

function of a catalyst substance added in a sub-stoichiometric amount is to lower the reaction

activation energy and affect selectivity for chemical transformations without being consumed62

Homogeneous catalysts have a long prevalence in industry with applications ranging from bulk

chemicals to complex multi-step processes Among the most prominent examples are the

Monsanto and Cativa processes for the carbonylation of methanol to produce acetic acid and the

oxo process for hydroformylation of olefins to yield aldehydes63 Only touching the tip of the

iceberg other commercial processes include the Wacker process for the oxidation of ethylene

aforementioned Ziegler-Natta olefin polymerization based on immobilized TiCl3 and substrate

hydrogenations using Wilkinsonrsquos Rh and Ru catalysts64-65 Other noteworthy discoveries

essential to the advancement of catalysis include Fischer-Tropsch production of liquid

hydrocarbons asymmetric catalysis olefin metathesis and Pd-catalyzed cross couplings66

The significance of catalysis for the development of chemistry has been recognized by the Nobel

Prize Committee with the earliest accreditation in the field awarded in 1909 to W Ostwald

Shortly thereafter Nobel Prizes were awarded for important contributions by P Sabatier (1912)

F Haber (1918) and C Bosch and F Bergius (1931) Since the turn of the millennium catalysis

has been recognized with four Chemistry Nobel Prizes awarded to 10 laureates66

13 Frustrated Lewis Pairs

131 Early discovery

The acid-base theory proposed by G N Lewis in 1923 is arguably one of the most important

theories in chemistry describing Lewis acid and base species as electron pair acceptors and

electron pair donors respectively67 According to the theory sterically unhindered Lewis acid-

base pairs react to form a Lewis adduct quenching subsequent reactivity This concept is

fundamental in most areas of chemistry involving the interaction of a doubly occupied orbital

(nucleophile) with an empty orbital (electrophile) forming a favourable overlap

Recent advances involving sterically encumbered Lewis pairs preclude such adduct formation

thereby rendering the individual components available for unique reactivity68-70 Astonishingly

in 1942 H C Brown reported that the ldquosteric strainrdquo between the Lewis acid trimethylborane

and the bulky Lewis base 26-lutidine does not result in adduct formation71 These early results

predate the recently popularized concept of frustrated Lewis pairs (FLPs) describing the

6

combination of Lewis acids and bases with sterically and electronically frustrated substituents

which prevent formal adduct formation32 The cooperative behaviour of these frustrated Lewis

centres has been evidenced to activate small molecules72

132 Hydrogen activation and mechanism

The first FLP reactivity was discovered by Stephan et al in 2006 while investigating the

chemistry of phosphonium borate linked zwitterions R2P(H)(C6F4)B(F)(C6F5)2 (R = alkyl or

aryl) generated from nucleophilic aromatic substitution of B(C6F5)3 by bulky secondary

phosphines31 Treatment with Me2SiHCl easily converts the linked zwitterion to the

phosphonium borohydride species containing both protic and hydridic hydrogen atoms In a

remarkable example the linked PHndashBH zwitterion (R = Mes) was found to liberate and rapidly

activate H2 representing the first example of reversible H2 activation using main group

compounds (Scheme 13)

Scheme 13 ndash Reversible H2 activation by linked phosphine-borane FLP

Hydrogen activation by main group compounds is rare the first example was reported in 2005

by the group of Power and co-workers describing the addition of H2 to heavier main group

digermyne compounds RGeequivGeR (R = aryl)30 The seminal finding was followed by the work of

Bertrand using bulky (alkyl)(amino)carbenes displaying both nucleophilic and electrophilic

characteristics to split and add H2 at a single carbon centre28 In a succeeding report by Piers the

antiaromatic Lewis acid perfluoropentaphenylborole was exclusively employed in H2 activation

to yield boracyclopent-3-ene products resulting from H2 addition to the two carbon atoms alpha

to boron73

After the initial breakthrough with FLPs their unique reactivity attracted immediate attention of

the scientific community Erker and co-workers have synthesized intramolecular PB FLPs

derived by the anti-Markovnikov addition of HB(C6F5)2 to vinyl phosphines (Scheme 14 a)74-75

Additionally Rieger and Repo have reported the nitrogen-based intramolecular FLP ansa-

7

aminoborane shown in Scheme 14 (b)76-78 These systems heterolytically split H2 albeit

reversible H2 activation was only demonstrated for the ansa-aminoborane

Hydrogen activation has also been extended to bimolecular systems Combinations of B(C6F5)3

and sterically encumbered tertiary phosphines were found to effect H2 activation (Scheme 14

c)32 In one example the weaker Lewis acid B(p-HC6F4)3 and o-tolyl3P were found to liberate H2

under vacuum79-80


activation by an NB FLP (b) and H2 activation by an intermolecular PB FLP (c)

The initial mechanism proposed for heterolytic splitting of H2 was speculated to be a ldquoside-onrdquo

or ldquoend-onrdquo coordination of H2 to either the boron or phosphorus moiety followed by approach

of the respective FLP partner effecting H-H bond cleavage This mechanism was not found to be

computationally supported despite earlier evidence for the ldquoside-onrdquo mechanism based on BH3-

H2 adducts81-84 While mechanistic details remain debated theoretical investigations by the

groups of Paacutepai85-87 and Grimme88 were performed on the prototype tBu3PB(C6F5)3 FLP Both

groups agree on the formation of an ldquoencounter complexrdquo stabilized by CndashH---F dispersion

interactions between the phosphine methyl groups and C6F5 borane rings As a result the Lewis

pair orient such that the boron is in close proximity to the phosphorus centre The electron

transfer model proposed by Paacutepai89 explains hydrogen activation by synergistic interaction of the

8

Lewis pair inducing polarization on the H2 molecule effecting heterolytic cleavage In this case

donation from the σ orbital of H2 into the empty orbital on the Lewis acid occurs in conjunction

with lone pair donation from the Lewis base to the σ orbital of H2 representing a process

similar to metal-based heterolytic cleavage of H2 (Figure 11 a) In contrast the electric field

model reported by Grimme suggests heterolytic H2 activation is a barrierless process resulting

from the exposure of H2 to a sufficiently strong homogeneous electric field pocket created by the

FLP complex Interpretation of this model does not consider electron donation or the orbitals of

the FLP or H2 (Figure 11 b)


field (b) models representing H2 cleavage

Direct investigation of H2 activation intermediates by standard experimental techniques has been

unquestionably demanding Experimental evidence of an encounter complex has been observed

by 19F1H HOESY NMR studies revealing contacts between all protons of R3P (R = tBu Mes)

and fluorine nuclei of B(C6F5)3 although only a rough orientation of the molecules was

reported90 Examination of a related system has recently been reported by the Piers group In this

case combination of a highly electrophilic boraindene and Et3SiH gave an isolable borane-silane

complex affirming details of adduct formation in FLP hydrosilylation and to a certain extent

extrapolated to the closely related H2 activation reaction (Scheme 15)91

9


adduct at 195 K

133 Substrate hydrogenation

Reversible H2 activation by the initial FLP Mes2P(H)(C6F4)B(H)(C6F5)2 was a landmark

discovery that shed light onto potential important applications of such systems Most significant

of these efforts was demonstrated by employing R2P(H)(C6F4)B(H)(C6F5)2 (R = tBu Mes) in the

catalytic reduction of unsaturated substrates specifically bulky imines and N-protected nitriles to

corresponding amines using 5 mol catalyst 5 atm of H2 and temperatures ranging from 80 -

100 degC Concerted investigations in the field revealed that sterically hindered substrates could

also serve as the Lewis base in splitting hydrogen92-93 To this end catalytic amounts of B(C6F5)3

in combination with various bulky aldimines and ketimines were reduced under 5 atm of H2 at

120 degC with isolated yields in the range of 89 - 99 Based on experimental observations the

proposed mechanism suggests H2 is cleaved between the bulky imine and B(C6F5)3 followed by

hydride delivery to the iminium cation (Scheme 16)

Scheme 16 ndash Proposed mechanism for B(C6F5)3 catalyzed reduction of imines

10

Following the early reports on metal-free catalytic hydrogenation the reduction of various other

substrates has been demonstrated to include aziridines92 94 enamines93 enones95 silyl enol

ethers96-97 N-heterocycles98 olefins99 and most recently alkynes have been reduced to cis-

alkenes100 Asymmetric hydrogenation by chiral FLPs was first demonstrated in 2008 by

Klankermayer and co-workers to give a chiral amine with 13 ee and later improvements up to

83 were obtained using a camphor derived catalyst101-102 Rieger and Repo saw ee values of

3776 103 while significant improvements up to 89 were achieved by the Du group104

Recently borenium cations have been used as Lewis acids in FLP chemistry with remarkable

catalytic activity for the hydrogenation of imines and enamines at room temperature (Figure

12)105

Figure 12 ndash A highly efficient borenium hydrogenation catalyst

134 Activation of other small molecules

FLP-mediated bond activations have been explored for a multitude of small molecules including

CO2106-107 N2O108-112 SO2113-114 NO115-116 CO107 117-119 NSO120 fluoroalkanes121 ether122

disulfides123 alkenes124-125 and alkynes126-128 FLPs have also been exploited in radical

polymerizations116 and more recently in materials and surface science129 Efforts have also

continued to exploit FLP chemistry in synthetic organic applications130 Beyond here small

molecule transformations that are relevant to the chemistry presented in this thesis will be

discussed

1341 Unsaturated hydrocarbons

Reactivity of unsaturated hydrocarbons has been a field traditionally associated with transition

metal chemistry and has found particular use for organic synthesis131-138 The dramatic evolution

in FLP systems has raised interest in probing the reactivity of main group complexes with

alkenes and alkynes100 139-140 This reactivity is reminiscent of related findings by Wittig and

Benz in 1959 involving the addition of Ph3P and BPh3 to benzyne affording zwitterionic

11

phosphonium-borates141 In the same context Tochtermann showed the addition of the bulky

carbanion [Ph3C]- and Lewis acid BPh3 across the double bond of 13-butadiene rather than

anionic polymerization of the conjugated diene142

1342 Alkenes

The reaction of FLPs with alkenes is particularly intriguing as the individual Lewis components

do not react with the substrate rather the three component combination of R3P B(C6F5)3 and

alkene exhibited intermolecular 12-addition reactions (Scheme 17 top)143-144 Similar activation

results were also observed upon exposure to the ethylene-linked FLP Mes2PCH2CH2B(C6F5)2145-

147 In two remarkable examples the Stephan group provided spectroscopic theoretical148 and

crystallographic149 evidence for Lewis acid-olefin van der Waals complexes forming prior to

FLP additions (Scheme 17 bottom)


equilibrium between ldquoopenrdquo and ldquoclosedrdquo form of a tethered olefin-borane species (bottom)

1343 Alkynes

Initial reactivity of FLPs with terminal alkynes featured the facile deprotonation or addition of

phosphineLewis acid (B Al) combinations to afford alkynylborate (aluminate) salts or

zwitterions with selectivity of the reaction correlated to the basicity of the phosphine (Scheme

18)126 128 In a joint report by the Stephan and Erker groups the B(C6F5)3-mediated

intramolecular cyclization of an ortho-ethynylaniline to access a cyclic anilinium borate was

presented150-151 In an analogous fashion Stephan and co-workers showed the cyclization of

alkyne- and alkene-tethered pyridines and quinolines using B(C6F5)3152 The groups of Berke

12

Erker Stephan and Uhl expanded the chemistry by varying the Lewis acid to BPh3 and alanes153

as well as the Lewis base to include phosphines154 polyphosphines155 thioethers amines and

pyridines156 carbenes157 and pyrroles158

Scheme 18 ndash Reaction of FLPs with phenylacetylene

1344 11-Carboboration

Particularly prolific in the research area of FLP reactivity with alkynes the groups of Erker and

Berke separately unravelled the 11-carboboration reaction resulting from the electrophilic

attack of the CequivC triple bond of an alkyne by highly electrophilic boranes RB(C6F5)2 generating

alkenylborane products (Scheme 19)156 159-160

Scheme 19 ndash 11-Carboboration reaction of terminal (top) and internal alkynes (bottom)

In the absence of a Lewis base the combination of electrophilic boranes and terminal alkynes are

postulated to generate a vinylidene intermediate stabilized by 12-hydride migration to the

carbocation Subsequently scission of a BndashC bond transfers a substituent from the borane to the

same carbon of the alkyne generating the alkenylborane (Scheme 110 left)159 This simple yet

elegant strategy demonstrates a facile route to borane derivatives with a C(sp2)-B centre that

could be further treated under Suzuki cross-coupling conditions161 In the presence of a Lewis

13

base deprotonation of the vinylidene or nucleophilic addition at the carbocation takes place

(Scheme 110 right)


(right) and absence (left) of a Lewis base

1345 CO2 and SO2

Following the reactivity of FLPs with olefins successful joint efforts by the Stephan and Erker

groups showed the activation of the greenhouse gas CO2 and acid rain contributor SO2 using the

FLP tBu3PB(C6F5)3 and ethylene-linked PB system Mes2PCH2CH2B(C6F5)2 (Scheme 111 a

and b)113-114 Key differences were observed in the reactivity of the two gases For example the

reversible nature of binding CO2 was not observed with the SO2 bound species Furthermore the

six-membered SO2 adducts derived from linked PB FLPs gave a stereogenic sulphur centre

resulting in a pair of isomers (Scheme 111 b) The Stephan group extended the activation of

CO2 beyond borane Lewis acids To this end 12 combinations of bulky phosphines and AlX3 (X

= halide or C6F5) react with CO2 rapidly leading to the formation of R3P(CO2)(AlX3)2 (Scheme

111 c)

14

Mes2P B(C6F5)2

EO2Mes2P B(C6F5)2

E O

O

R R

gt -20 degC- CO2

tBu3P B(C6F5)3EO2

80 degC- CO2

PB(C6F5)3E

O

O

tBu3

Mes3P 2 AlX3 Mes3PAlX3E

O

O

AlX3

CO2

b)

a)

c)


FLPs activation of CO2 using PAl FLP (c) (R = H Me E = C S X = Br I)

In the case of CO2 further chemical transformation of the activated molecule has been

presented107 111 153 162-164 including efforts to reduce CO2 to CH3OH The groups of Ashley and

OrsquoHare presented this reactivity using H2 as the reducing source Stephan et al used ammonia

borane165 and this process has been achieved catalytically by Fontaine using hydroboranes166-168

Additionally Piers reported the catalytic deoxygenative reduction of CO2 to CH4 using silanes169

and Stephan showed the stoichiometric reduction of CO2 to CO using R3PAlX3 FLPs170

1346 FLP activation of carbonyl bonds

Efforts to include oxygen-based substrates in FLP-mediated catalytic transformations have found

limited success due to the high affinity of electrophilic boranes towards oxygen species72 171

Investigations by Erker and co-workers described the irreversible capture of benzaldehyde and

trans-cinnamaldehyde at the C=O functional group by the intramolecular FLP

Mes2PCH2CH2B(C6F5)2 (Scheme 112 top)172-173 Similar alkoxyborate products were obtained

in the reaction of NB FLPs with benzaldehyde (Scheme 112 bottom)174

15


(bottom) FLPs

1347 Carbonyl hydrogenation

Metal-free hydrogenation of carbonyl substrates was reported as early as 1961 by Walling and

Bollyky for the homogeneous hydrogenation of ketones catalyzed by alkali metal alkoxides175

About 40 years later Berkessel and co-workers communicated mechanistic studies on the

process which were supported thereafter by computational investigations176 The authors

elucidated mechanistic analogies between base-catalyzed ketone hydrogenation and Ru-

catalyzed transfer hydrogenation by Noyori whereby a Broslashnsted base participates in H2

heterolysis177 Although this is the first example of metal-free reduction of ketone the reactions

are performed at relatively harsh conditions requiring 100 atm of H2 and 200 degC Moreover the

substrate scope was limited to the non-enolizable ketone benzophenone

The reaction of benzaldehyde with the intramolecular H2-activated FLP

R2P(H)(C6F4)B(H)(C6F5)2 (R = tBu Mes) was found to proceed in a stoichiometric fashion

reducing the C=O double bond formulating the zwitterion R2P(H)(C6F4)B(C6F5)2OCH2Ph

(Scheme 113) Chemical intuition would perhaps point to proton transfer from the phosphonium

centre this is however prevented by the lower basicity of the oxygen atom contrasting

hydrogenation reactions with nitrogen substrates

16

B(C6F5)2R2P

FF

F F

H

H

O

HPhB(C6F5)2R2P

FF

F F

H O

Ph

R = tBu Mes


borohydride FLP

Based on the principle for catalytic hydrogenation of imines Repo and co-workers explored

C=O hydrogenations using the aromatic carbonyl substrates benzophenone and benzaldehyde as

Lewis bases along with the Lewis acid B(C6F5)3 Experimental results indicated the reaction to

be challenging generating only sub-stoichiometric amounts of the alcohol products due to rapid

decomposition of the borane178

1348 Carbonyl hydrosilylation

Hydrosilylation is one of the most commonly applied processes within the chemical industry

today New catalytic technologies providing avenues for metal-free SindashH bond activation have

become appealing alternatives to traditional transition metal catalysts179 Impressively in 1996

the Piers group reported 1 - 4 mol of B(C6F5)3 to effect the catalytic hydrosilylation of

aromatic aldehydes ketones and esters at room temperature (Scheme 114 top)180-182 Clever

analysis of the mechanism by Oestreich using a stereochemically pure silane found inversion of

stereochemistry at silicon after hydrosilylation This finding rationalized a concerted SN2 type

displacement at the silicon centre of a (C6F5)3Bδ-middotmiddotmiddotHmiddotmiddotmiddot SiR3δ+ transition state by the substrate

carbonyl oxygen (Scheme 114 bottom)183

17


using Ph3SiH (top) stereochemical analysis of the hydrosilylation mechanism (bottom)

14 Scope of Thesis

The objective of this graduate research was to expand the scope of FLP reactions using the Lewis

acid B(C6F5)3 Although previous studies have documented the reactivity of B(C6F5)3 with small

molecules further transformation of the activated species in organic syntheses remains limited

In this work FLP hydrogenation reactions were extended to include the aromatic rings of N-

phenyl amines and N-heterocyclic compounds as described in Chapter 2 Tandem hydrogenation

and transannulation reactions occurred with a para-methoxy substituted aniline affording a 7-

azabicyclo[221]heptane derivative Mechanistic studies of this reactivity provided insight to a

viable approach achieving the catalytic hydrogenation of ketones and aldehydes to form alcohol

products presented in Chapter 3 In addition the reductive deoxygenation of aryl ketones to

aromatic hydrocarbons was investigated Finally Chapter 4 expands FLP catalytic reactions

beyond hydrogenations In this chapter B(C6F5)3 catalyzed hydroamination of terminal alkynes

is investigated with extension to intramolecular systems and stoichiometric hydrophosphination

reactions

All synthetic work and characterizations were performed by the author with the exception of

elemental analyses high resolution mass spectroscopy and X-ray experiments DFT calculations

for the aromatic hydrogenations described in Chapter 2 were performed by Professor Stefan

Grimme at Universitaumlt Bonn Germany Compounds 216 - 218 were initially synthesized by an

undergraduate student Jon Nathaniel del Castillo under the authorrsquos supervision The synthesis

of compounds 439 and 440 were initially performed by the author at the University of Toronto

18

and repeated during a four month research opportunity program in the laboratory of Professor

Gerhard Erker at Universitaumlt Muumlnster Germany Compounds 441 and 442 were prepared at

Universitaumlt Muumlnster and the structure of 442 was obtained and solved by Dr Constantin

Daniliuc All other molecular structures were solved by the author and the authorrsquos supervisor

Professor Douglas Stephan

Portions of each chapter have been published or accepted at the time of writing

Chapter 2 1) Voss T Mahdi T Otten E Froumlhlich R Kehr G Stephan D W Erker G

ldquoFrustrated Lewis Pair Behavior of Intermolecular AmineB(C6F5)3 Pairsrdquo Organometallics

2012 31 2367-2378 2) Mahdi T Heiden Z M Grimme S Stephan D W ldquoMetal-Free

Aromatic Hydrogenation Aniline to Cyclohexylamine Derivativesrdquo J Am Chem Soc 2012

134 4088-4091 3) Mahdi T Castillo J N Stephan D W ldquoMetal-Free Hydrogenation of N-

based Heterocyclesrdquo Organometallics 2013 32 1971-1978 4) Longobardi L E Mahdi T

Stephan D W ldquoB(C6F5)3 Mediated Arene HydrogenationTransannulation of para-

Methoxyanilinesrdquo Dalton Trans 2015 44 7114-7117

Chapter 3 5) Mahdi T Stephan D W ldquoEnabling Catalytic Ketone Hydrogenation by

Frustrated Lewis Pairsrdquo J Am Chem Soc 2014 136 15809-15812 6) Mahdi T Stephan D

W ldquoFacile Protocol for Catalytic Frustrated Lewis Pair Hydrogenation and Reductive

Deoxygenation of Ketones and Aldehydesrdquo Angew Chem Int Ed 2015 DOI

101002anie201503087

Chapter 4 7) Mahdi T Stephan D W ldquoFrustrated Lewis Pair Catalysed Hydroamination of

Terminal Alkynesrdquo Angew Chem Int Ed 2013 52 12418-12421 8) Mahdi T Stephan D

W ldquoInter- and Intramolecular Hydroamination of Terminal Alkynes by Frustrated Lewis Pairsrdquo

Chem Eur J 2015 accepted

19

Chapter 2 Metal-Free Aromatic Hydrogenation of N-Phenyl Amines

and N-Heterocyclic Compounds

21 Introduction

211 Hydrogenation

Hydrogenation the addition of hydrogen (H2) to unsaturated compounds is one of the simplest

and most attractive chemical processes performed today26 The reaction is employed for the

production of commodity chemicals with widespread application in the petrochemical

pharmaceutical and foods industries One of the largest industrial applications of hydrogenation

is in the Haber-Bosch process63 66 184 This method uses N2 and H2 to produce ammonia which is

essential for the synthesis of nitrogen fertilizers currently sustaining about one-third of the

worldrsquos population Additionally significant is the Fischer-Tropsch process used to generate

liquid hydrocarbons from the chemical reaction of H2 and CO (synthesis gas)185-186

In the early part of the 20th century P Sabatier discovered the catalytic hydrogenation of organic

substrates over finely divided nickel thereby greatly advancing the field of organic chemistry187-

193 Approximately 60 years later Wilkinson uncovered the homogeneous hydrogenation of

olefins using Ru and Rh catalysts a development that was crowned initiator of organometallic

chemistry (Scheme 21 a)194-197 Further developments in metal-based hydrogenations were

made in the 1980s including the Nobel Prize winning work of asymmetric hydrogenations by

Noyori and Knowles (Scheme 21 b)198-207 While precious metal catalysts208-209 are known to

carry out this reactivity (Scheme 21 c) the high cost and low abundance of these metals

necessitates the development of more cost-efficient procedures New technologies providing

avenues for greener transformations have recently been illustrated using first-row transition

metals Fe and Co (Scheme 21 d)136 210-214

20


and Chirik (d) py = pyridine

212 Transfer hydrogenation

A variety of insightful strategies have provided alternative avenues to direct hydrogenation One

such example is transfer hydrogenation the addition of hydrogen to an unsaturated substrate

from a source other than gaseous H2 In the 1920s Meerwein Ponndorf and Verley (MPV)

demonstrated the first example of hydrogen transfer from a sacrificial alcohol to ketone using an

aluminum alkoxide catalyst215-217 Nonetheless interest in using organocatalysts for

hydrogenation reactions increased spectacularly due to novelty of the concept efficiency and

selectivity in organic reactions Particularly recognized are chiral amine catalysts in combination

with Hantzsch ester dihydropyridines which act as mild organic sources of H2218-219 Extensive

research has also focused on new transition metal catalysts for efficient dehydrocoupling of

ammonia borane (H3NBH3) and related amine borane compounds220

Although transfer hydrogenation is a process dominated by precious transition metal catalysts

Earth abundant less toxic Fe-based catalysts have proven remarkably active effecting high

enantioselectivity (Figure 21 a)221 Moreover catalyst-free strategies by Berke and co-workers

have promoted transfer hydrogenation of imines and polarized olefins222 Stephan et al

underscored extension of metal-free catalysis reporting a highly electrophilic phosphonium

cation catalyst for application in dehydrocoupling of protic compounds with silanes and transfer

hydrogenation to olefins (Figure 21 b)223

RhPh3P

Ph3P Cl

PPh3

(a) (b) (c)

(d)

21


cation (b) used for transfer hydrogenation catalysis

213 Main group catalysts

The discovery of sodium borohydride and lithium aluminum hydride in the 1940s introduced

new stoichiometric methods for the hydrogenation of unsaturated functional groups56 59 224 A

variety of these metal hydride reagents possessing a high degree of chemoselectivity have made

the reduction of a broad range of functional groups possible although catalytic procedures are

evidently more desirable In this vein the first non-transition metal catalyst for ketone

hydrogenation employing tBuOK and H2 is regarded as a breakthrough175-176 Early main group

metal catalysts have followed with highlights on a well-defined organocalcium catalyst

developed by Harder225 and the first cationic calcium hydrides by Okuda capable of catalytic

hydrogenation of 11-diphenylethylene226

Renaissance in main group chemistry emerged with the discovery of frustrated Lewis pairs

(FLPs) These relatively common main group reagents have been applied in the hydrogenation of

imines nitriles aziridines enamines silyl enol ethers olefins and alkynes typically using boron

Lewis acids relying on perfluoroaryl substituents227-228 More recently Lewis acidic borenium

ions based on an [NHC-9-BBN]+ framework have also proven ideal for hydrogenation of imine

and enamine substrates105 Du et al described the highly enantioselective hydrogenation of

imines using a chiral borane catalyst derived from the hydroboration of chiral diene

substituents104 Alkyl229 and aryl149 aluminum compounds in addition to metal-activated carbon-

based Lewis acids have been shown to participate in similar reactivity230

(a) (b)

22

214 Hydrogenation of aromatic and heteroaromatic substrates

2141 Transition metal catalysts

Despite advancements in hydrogenation catalysis the reduction of arenes and heteroaromatics to

saturated cyclic hydrocarbons remains challenging and is typically performed in the

heterogeneous phase using transition metal catalysts Such hydrogenations find particular use in

the petrochemical industry to convert alkene and aromatic fossil fuels into liquid hydrocarbons

before application in commodities such as synthetic fuel26 231 The number of complexes capable

of this catalysis is scarce mainly due to the high energy barrier required to disrupt aromaticity

Catalytic hydrogenation of aromatic systems was first demonstrated for phenols anilines and

benzene in the early 1900s by P Sabatier using powdered nickel189-193 Soon after the 14-

reduction of anisole was observed using dissolved alkali metals in liquid ammonia with major

developments emerging to include benzene and naphthalene derivatives232-233 Historically

significant accomplishments include the work of R Adams using finely divided platinum oxide

(Adamrsquos catalyst)234 and M Raney based on digestion of alloys to form finely divided metal

samples (Raney nickel)235 Other highly efficient catalysts include organometallic compounds

particularly Co Ni Ru and Rh deposited on to oxide surfaces236-239

The number of homogeneous systems capable of hydrogenating arene substrates lags well behind

heterogeneous systems The first well-documented homogeneous catalyst is a simple allylcobalt

complex η3-C3H5Co[P(OMe)3]3 reported by Muetterties and co-workers operating at room

temperature (Figure 22 left)240 shadowed by a new generation of TaV and NbV hydride catalysts

featuring bulky ancillary aryloxide ligands by Rothwell (Figure 22 right)241-243 It is noteworthy

that metal complexes of the cobalt group have provided valuable mechanistic information on this

transformation231 Ziegler type catalysts consisting of Ni or Co alkoxides acetylacetonates or

carboxylates with trialkylaluminum activators have also been demonstrated in the large scale

Institut Francais du Petrole (IFP) process231

23


homogeneous hydrogenation of aromatic substrates

2142 Metal-free catalysts

Non-metal mediated routes such as the facile addition of borohydrides to unsaturated bonds

were developed early on by Brown and co-workers244 To this extent Koumlster has reported the

hydroboration and subsequent hydrogenolysis to convert naphthalenes to tetralins and

anthracenes to coronenes at 170 - 200 degC and 25 - 100 atm of H2245-246 Alternative efforts

demonstrated trialkylborane and tetraalkyldiborane catalysts in hydrogenating olefins and

polycyclic aromatic hydrocarbons including coal tar pitch In another finding homogeneous

iodine and borane catalysts were shown to hydrogenate the aromatic units of high-rank

bituminous coals at temperatures above 250 degC and 150 - 250 atm of H226 In a recent report the

Wang group has demonstrated the hydrogenation of unfunctionalized olefins catalyzed by

HB(C6F5)2247

215 Reactivity of FLPs with H2

The feasibility of FLP systems to activate H2 and hydrogenate unsaturated substrates

particularly heteroaromatic rings has been examined In this respect 26-lutidine and B(C6F5)3

exhibit reversible dissociation of the Lewis acid-base adduct providing a FLP-mode to H2

activation (Scheme 22 a)248-249 Similar acid-base equilibria were observed with N-heterocycles

nonetheless a catalytic amount of B(C6F5)3 and H2 results in reduction of the N-heterocyclic ring

(Scheme 22 b)98 Research by the Sooacutes group extended the scope of such catalytic reductions

using specifically designed Lewis acids250

24


quinoline to 1234-tetrahydroquinoline (b)

Following these reports the commercially available Lewis acid B(C6F5)3251-252 was explored in

the hydrogenation of aromatic rings This chapter will describe results in metal-free aromatic

hydrogenation of N-bound phenyl rings of amines imines and aziridines in addition to pyridines

and N-heterocycles While these reductions are stoichiometric they represent rare examples of

homogeneous aromatic reductions that are metal-free and performed under comparatively mild

conditions Moreover the tandem hydrogenation and intramolecular cyclization of a para-

methoxy substituted aniline is presented This reaction provides a unique route to a 7-

azabicyclo[221]heptane derivative

22 Results and Discussion

221 H2 activation by amineborane FLPs

Phosphine-based FLPs have been thoroughly investigated in the activation of small molecules

and particularly revolutionizing is the first demonstration of reversible heterolytic H2 activation

by Mes2P(C6F4)B(C6F5)231 The corresponding chemistry with amineborane FLP systems has

been less explored Combination of the bulky amine tBuNHPh and an equivalent of B(C6F5)3 in

C6D5Br or pentane solutions do not result an apparent interaction by 1H 11B and 19F NMR

spectroscopy indeed supporting the ldquofrustratedrdquo nature of the system Following exposure of this

solution to H2 (4 atm) at 25 degC the gradual precipitation of a white solid was observed and after

12 h the H2 activated species [tBuNH2Ph][HB(C6F5)3] 21 was isolated in 82 yield (Scheme

23 top) The 1H NMR spectrum obtained in C6D5Br showed a broad resonance at 715 ppm

attributable to an NH2 fragment integrating to two protons as well as signals assignable to the

25

phenyl and tBu groups In addition 11B NMR spectroscopy revealed a doublet at -240 ppm (1JB-

H = 78 Hz) and 19F resonances were observed at -1335 -1613 and -1650 ppm These data

along with elemental analysis were consistent with the formulation of 21 Similar treatment of

the diamine 14-C6H4(CH2NHtBu)2 with two equivalents of B(C6F5)3 in toluene and exposure to

H2 (4 atm) resulted in formation of a precipitate at 25 degC Subsequent isolation of the product

afforded quantitative yield of the salt [14-C6H4(CH2NH2tBu)2][HB(C6F5)3]2 22 (Scheme 23

bottom) The 1H NMR data showed signals at 595 ppm and 339 ppm attributable to the NH2

and BH fragments respectively The 11B and 19F NMR signals were consistent with the presence

of the [HB(C6F5)3]- anion


to make 21 (top) and 22 (bottom)

222 Aromatic hydrogenation of N-phenyl amines

Repetition of the H2 activation reaction between tBuNHPh and B(C6F5)3 in toluene with heating

at 110 degC for 48 h led to formation of a new product 23 Subsequent workup and

characterization by NMR spectroscopy revealed the presence of the [HB(C6F5)3]- anion The 1H

NMR spectrum displayed a broad resonance at 507 ppm attributed to an NH2 moiety while

aromatic resonances were notably absent Instead multiplets between 272 and 090 ppm along

with a sharp singlet at 091 ppm were observed This data was consistent with the identity of 23

as the cyclohexylamine product [tBuNH2Cy][HB(C6F5)3] (Scheme 24) By 1H NMR

spectroscopy after 48 h at 110 degC the reaction constituted approximately complete conversion

to 23 and was isolated in 84 yield (Table 21 entry 1)

26

Scheme 24 ndash Aromatic hydrogenation of tBuNHPh to give 23

Treatment of iPrNHPh with an equivalent of B(C6F5)3 in toluene at 25 degC gave the

crystallographically characterized adduct (iPrNHPh)B(C6F5)3 24rsquo (Figure 23) This compound

exhibited broad resonances in the 1H 11B 13C and 19F NMR spectra at RT indicating a

fluxional adduct Upon cooling the sample to 193 K NMR signals coalesce giving distinct

resonances assignable to the adduct along with 15 inequivalent 19F resonances that are consistent

with a barrier of rotation of the pentafluorophenyl rings

Figure 23 ndash POV-Ray depiction of 24rsquo

Introducing the amine-borane adduct 24rsquo to H2 (4 atm) does not result in any noticeable changes

in the NMR spectra at RT Although thermolysis of the sample up to 70 degC eventually reveals

dissociation of the adduct with concurrent hydrogenation giving products of complete and partial

reduction of the phenyl ring The partially reduced product observed in trace amounts consisted

of olefinic resonances at 577 and 553 ppm and corresponding aliphatic signals at 256 and 222

ppm (Figure 24 insets) Extensive 1H1H COSY and 1H13C HSQC NMR studies confirmed

the compound as the partially hydrogenated 3-cyclohexenyl derivative [3-

(C6H9)NH2iPr][HB(C6F5)3] the cation is depicted in Figure 24

27


partially hydrogenated cation [3-(C6H9)NH2iPr]+

Repeating the reaction at 110 degC for 36 h resulted in complete reduction of the aromatic ring

affording the salt [iPrNH2Cy][HB(C6F5)3] 24 in 93 yield (Table 21 entry 1) Monitoring the

reaction in a J-Young tube by 1H NMR spectroscopy at 110 degC showed the gradual growth of the

cyclohexyl methylene resonances with the corresponding consumption of aromatic signals

(Figure 25)


iPrNHPh consumption to form 24 iPr methine for iPrNHPh () and [iPrNH2Cy]+ ($)

12 h

9 h

6 h

3 h

15 h

05 h

$

HB HA

28

The hydrogenation protocol was applied to PhCyNH and Ph2NH affording [Cy2NH2][HB(C6F5)3]

25 in yields of 88 and 65 respectively (Table 21 entry 2) Monitoring the reaction of Ph2NH

at 24 h intervals by 1H NMR spectroscopy did not show evidence for formation of PhCyNH

presumably this indicates that complete hydrogenation of both arene rings occurs prior to

addition of the first equivalent of hydrogen to another molecule of Ph2NH In addition to the

NMR spectroscopy data formulation of 24 and 25 were determined via X-ray crystallography

(Figure 26)

Figure 26 ndash POV-Ray drawings of 24 (left) and 25 (right)

In an analogous fashion further substrates explored in such reductions included iPrNH(2-

MeC6H4) iPrNH(4-RC6H4) (R = Me OMe) iPrNH(3-MeC6H4) and iPrNH(35-Me2C6H3)

affording the arene-reduced products [iPrNH2(2-MeC6H10)][HB(C6F5)3] 26 [iPrNH2(4-

RC6H10)][HB(C6F5)3] (R = Me 27 OMe 28) [iPrNH2(3-MeC6H10)][HB(C6F5)3] 29 and

[iPrNH2(35-Me2C6H9)][HB(C6F5)3] 210 in yields of 77 73 61 82 and 48 respectively (Table

21 entries 3 - 5) In cases where the hydrogenation reactions yield a chiral centre a mixture of

diastereomers was observed

Previously the Stephan group reported the catalytic hydrogenative ring-opening of cis-123-

triphenylaziridine using 5 mol B(C6F5)3 and H2 (4 atm) to give PhNHCHPhCH2Ph in 15 h at

120 degC94 In the following case however employing one equivalent of B(C6F5)3 at 110 ordmC for 96

h resulted in reduction of the N-bound phenyl ring yielding the salt

[CyNH2CHPhCH2Ph][HB(C6F5)3] 211 (Table 21 entry 6) The 1H NMR data were in

agreement with formulation of the cation fragment with notable resonances at 588 and 461

ppm ascribed to the NH2 and methine groups respectively in addition to the phenyl

29

cyclohexyl methylene and BH signals 11B and 19F NMR spectra displayed resonances

characteristic of the [HB(C6F5)3]- anion

Table 21 ndash Aromatic reduction of N-phenyl amine substrates to N-cyclohexylammonium salts

30

Reduction of the imine PhN=CMePh to the corresponding amine has also been previously

reported to occur upon exposure of the imine to H2 using 10 mol B(C6F5)392 Under the same

conditions heating the substrate in the presence of one equivalent of B(C6F5)3 for 96 h gave

reduction of the N-bound aromatic ring affording the species [PhCH(Me)NH2Cy][HB(C6F5)3]

212 (Table 21 entry 7) Similarly reduction of 14-C6H4(N=CMe2)2 was observed on heating

for 72 h in the presence of two equivalents of B(C6F5)3 yielding 64 of the product [14-

C6H10(iPrNH2)2][HB(C6F5)3]2 213 (Table 21 entry 8) Aromatic reduction of the bis-arene (14-

C6H4iPrNH)2CH2 with two equivalents of B(C6F5)3 was also achieved affording [(14-

C6H10iPrNH2)2CH2][HB(C6F5)3]2 214 in 76 yield (Table 21 entry 9)

2221 Attempts at catalytic aromatic hydrogenation and hydrogenation of other aromatic substrates

Although this reaction is stoichiometric in B(C6F5)3 hydrogenation of one arene ring takes up

three equivalents of H2 In an attempt to effect reactivity using sub-stoichiometric combinations

of the Lewis acid 5 mol B(C6F5)3 was combined with iPrNHPh pressurized with H2 (4 atm)

and heated at 120 degC After 24 h 1H NMR data yielded complete conversion of the borane to the

[HB(C6F5)3]- anion with only 5 mol conversion of the aniline to the [iPrNH2Cy]+ cation The

remaining 95 of the initial aniline was unaltered Increasing the H2 pressure to 80 atm did not

improve reactivity The inability of the system to turnover could be explained by pKa values of

the conjugate acid for example iPrNHPh has a pKa value of 58 in H2O while the hydrogenated

product has a pKa of about 10 - 11 in H2O (iPr2NH2 pKa 1105 in H2O) thus preventing

reversible activation of H2253-254

Furthermore efforts to hydrogenate the arene ring of iPrNHPh using pre-H2 activated FLPs

[tBu3PH][HB(C6F5)3] [Mes3PH][HB(C6F5)3] and tBu2P(H)(C6F4)B(H)(C6F5)2 did not result in

any observable reactivity by NMR spectroscopy However the stoichiometric combination of the

zwitterion Mes2P(H)(C6F4)B(H)(C6F5)2 evolved H2 at elevated temperatures and ca 10 of

[iPrNH2Cy]+ was observed Similarly 10 mol of the catalyst combination 18-

bis(diphenylphosphino)naphthalene and B(C6F5)3 gave 10 of aromatic reduction as a result of

the borane

Stoichiometric reactions of B(C6F5)3 and the anilines (p-CH3PhO2S)NHPh tBuNH(C6F5) Boc-

NHPh EtNHPh imines 26-(Me2C6H3)N=C(H)Ph PhN=CMe(p-EtOPh) phenols TMSOPh

31

tBuOPh tBuO(p-CF3C6H4) tBuO(p-FC6H4) hydrazine PhNH-NHPh 18-naphthosultam Ph3P

ethers (p-FPh)2O and CF3SPh did not evidence hydrogenation of the arene ring under the

optimized reaction conditions Furthermore the reactivity of iPrNHPh with the boranes BPh3

MesB(C6F5)2 MesB(p-C6F4H)2 PhB(C6F5)2 B(p-C6H4F)3 and B(o-C6H4CF3)3 did not activate

H2 or hydrogenate the aniline arene ring

223 Mechanistic studies for aromatic hydrogenation reactions

2231 Deuterium studies

To gain mechanistic insight into the presented transformation tBuNHPh was combined in a J-

Young tube with an equivalent of B(C6F5)3 in C6H5Br and exposed to D2 (2 atm) at 25 degC After

standing for 12 h multinuclear NMR data certainly indicated heterolytic activation of D2 The 2H

NMR spectrum gave a broad singlet at 658 ppm assigned to a N-D bond and a broad resonance

at 326 ppm attributed to a B-D bond (Figure 27 bottom-left) In addition to the 11B and 19F

NMR spectra these data supported formation of [tBuNHDPh][DB(C6F5)3] 21-d2 After heating

the sample for 3 h at 110 degC the 2H NMR revealed significant diminishing in the B-D resonance

while the N-D resonance was visibly unaltered (Figure 27 top-left) The 1H NMR spectrum of

the corresponding sample evidenced a broad quartet at 325 ppm (1JB-H = 78 Hz) representative

of a B-H bond (Figure 27 top-right) This B-H resonance is absent in the 1H NMR spectrum of

the sample at RT after 24 h (Figure 27 bottom-right)



activation of HD and formation of [HB(C6F5)3]- at 110 degC (right)

Overall the following NMR studies are suggestive of reversible D2 activation in which at

elevated temperatures proton and deuteride from the nitrogen and boron centres of 21-d2

110 degC ND 110 degC BH (3 h) (3h) BD

RT ND BD RT (24 h) (24 h)

32

respectively combine releasing H-D The H-D gas is subsequently reactivated by the free amine-

borane FLP giving rise to [tBuND2Ph][HB(C6F5)3] (Scheme 25)

Scheme 25 ndash Reversible D2 activation by tBuNHPh and B(C6F5)3 to give HD

2232 Variable temperature NMR studies

As supported by the aforementioned deuterium studies the reversible nature of H2 activation by

the aromatic amines and B(C6F5)3 is consistent with observation of species 21 as the initial

product of hydrogenation This is followed by evolution and reactivation of H2 allowing access

to the arene reduced species 23 at elevated temperatures (Scheme 26)

Scheme 26 ndash Aromatic hydrogenation of 21 to give 23

This aspect of reversible H2 acitvation was further verified by variable temperature NMR studies

of the adduct (iPrNHPh)B(C6F5)3 24rsquo under H2 from 45 degC to 115 degC in C6D5Br As temperature

was increased both 11B and 19F NMR spectra displayed resonances pertaining to gradually

dissociating B(C6F5)3 and formation of the [HB(C6F5)3]- anion This is evidenced in Figure 28

by 11B NMR spectroscopy showing liberated B(C6F5)3 at 115 degC (11B δ 53 ppm) and progression

of the resonance at -25 ppm assignable to [HB(C6F5)3]- indicating formation of 24 It is

important to note that the [HB(C6F5)3]- resonance observed at the initiation of the reaction is

attributable to reversible hydride abstraction from the iPr substituent on the aniline

33



ppm [HB(C6F5)3]-)

2233 Theoretical calculations

The mechanism of this study is proposed based on quantum chemical calculations performed by

Professor Stefan Grimme at Universitaumlt Bonn Germany Quantum chemical calculations were

performed at the dispersion-corrected meta-double hybrid level (PW6P95 functional) employing

large triple-zeta type basis sets and TPSS-D3 optimized geometries This final theoretical level

denoted as PWP95-D3def2-TZVPPTPSS-D3def-TZVP provides reaction energies with an

estimated accuracy of about 1 - 2 kcalmol Solvation effects of toluene were considered using

the COSMO-RS continuum solvation model255

Theoretical studies indicate a mechanism that supports reactivity to initiate by dissociation of the

weak amine-borane adduct At this stage the FLP could follow two reaction pathways (Figure

29) At moderate temperatures the FLP undergoes splitting of H2 to yield the salt 21 computed

to be 97 kcalmol lower in energy than the amine-borane adduct However the free enthalpy

difference for this species is close to zero hence under equilibrium conditions it can be

considered as a resting state of the reaction This minor difference in free enthalpy is in

agreement with reversible D2 activation results presented earlier using tBuNHPh and B(C6F5)3

45 degC

75 degC

95 degC

65 degC

115 degC

55 degC

85 degC

105 degC

34

An alternative reaction pathway follows at elevated reaction temperatures In this case the

dissociated amine rotates to position the arene para-carbon towards the boron atom creating a

van der Waals complex that is stabilized by significant pi-stacking with a C6F5 group This

complex creates a classical FLP with an electric field to polarize the entrapped H2 and effect

heterolytic splitting at a relatively low energy barrier of 87 kcalmol The free enthalpy for H2

activation relative to the resting state is computed to be 212 kcalmol certainly supporting the

elevated temperatures required to effect this reactivity



relative to FLP + H2 (all data are in kcalmol)

At the transition state the H-H distance is calculated to be about 097 Aring This bond is

significantly elongated compared with PB FLPs where the bond distance ranges between 078

and 080 Aring thus signifying a delayed transition state The corresponding H-H and C-H covalent

Wiberg bond orders are 033 and 041 respectively The B-H bond order is 063 indicating

approximately half-broken and half-formed bonds in the transition state88 256

21

23

35

The resulting intermediate [tBuNHC6H6][HB(C6F5)3] (CH-intermediate) is an ion pair showing

an sp3 hybridized para-carbon and an almost planar tBuNH=C unit in the cation shown in Figure

29 This species has similar energy and free enthalpy to the arene-B(C6F5)3 van der Waals

compound The complexity of subsequent hydrogenation steps to yield 23 has limited further

computations

It is noteworthy that prolonged heating of the more basic amine iPr2NPh with B(C6F5)3 under H2

only yields [iPr2NHPh][HB(C6F5)3] 215 This suggests that the greater basicity of the nitrogen

centre in iPr2NPh (Et2NHPh pKa 66 in H2O) stabilizes 215 thereby inhibiting access to the

amine-borane FLP and subsequent arene reduction (iPrNHPh pKa 58 in H2O)253-254 The overall

proposed reaction mechanism has been summarized in Scheme 27 Observation of the partially

hydrogenated cation [3-(C6H9)NH2iPr]+ illustrated in Figure 24 is presumed to be a result of H2

activation at the ortho-carbon of the arene ring

Scheme 27 ndash Proposed reaction pathway to anilinium and cyclohexylammonium salts

224 Aromatic hydrogenation of substituted N-bound phenyl rings

2241 Fluoro-substituted rings and C-F bond transformations

Determining functional group tolerance of the demonstrated aromatic hydrogenations reaction

of the fluoro-substituted aniline (2-FPh)NHiPr with B(C6F5)3 under H2 indicated approximately

30 of the salt [(2-FPh)NH2iPr][HB(C6F5)3] after 31 h at RT Heating the sample at 110 degC for

36

24 h afforded a white solid 216a isolated in 59 yield (Scheme 28 a) Multinuclear NMR

spectroscopy revealed approximately 95 of the product consisted of [CyNH2iPr][FB(C6F5)3]

216a Spectral parameters of the cation were in agreement with that of compound 24 The

fluoroborate [FB(C6F5)3]- anionic fragment gave a broad signal at 055 ppm in the 11B NMR

spectrum and four 19F resonances were observed by 19F NMR spectroscopy at -1370 -1612 -

1669 and -1796 ppm The remaining 5 of the reaction mixture consisted of [(2-

FC6H10)NH2iPr][HB(C6F5)3] 216b Single crystals of 216a suitable for X-ray diffraction were

obtained and the structure is shown in Figure 210

Figure 210 ndash POV-Ray drawing of 216a

In a similar fashion heating the reaction of (3-FPh)NHiPr with B(C6F5)3 under H2 after 72 h

afforded the reduced product in 77 yield Approximately 95 of the salt consisted of 216a

and the remainder as [(3-FC6H10)NH2iPr][HB(C6F5)3] 217b (Scheme 28 b) Indeed these

examples illustrate tandem B(C6F5)3 mediated arene hydrogenation and C-F bond activation

Scheme 28 ndash Arene hydrogenation of (2-FPh)NHiPr (a) and (3-FPh)NHiPr (b) to give 216a

37

Analogous reactivity with (4-FPh)NHiPr gave partial hydrogenation of the ring after 72 h

forming the 3-cyclohexenyl derivative [(4-FC6H8)NH2iPr][HB(C6F5)3] 218 in 62 yield

(Scheme 29) In addition to the expected resonances a diagnostic doublet of triplets in the 1H

NMR at 495 ppm and doublet at 1584 ppm (1JC-F = 255 Hz) in the 13C1H NMR spectra

certainly indicate an unsaturated C=C bond with the fluorine atom still intact This was

unambiguously confirmed by X-ray crystallography (Figure 211) It is important to note that

approximately 20 of the isolated product consisted of 216a indicating a much reduced rate of

arene hydrogenation and C-F bond activation in comparison to ortho- or meta-F substituted

anilines In these two cases intial H2 activation is expected to occur through the resonance form

in which the lone pair is at the para carbon (Scheme 27) However in the case of para-F

substituted aniline H2 activation is speculated to preferentially occur through the resonance

structure in which the negative charge is at an ortho carbon This proposal is ascribed to the

electron-withdrawing fluoro substituent which removes electron density from the para position

The partially hydrogenated product 218 is analogous to the cation [3-(C6H9)NH2iPr]+ presented

in Figure 24 in which H2 activation is suggested to initiate at the ortho carbon

Scheme 29 ndash Arene hydrogenation of (4-FPh)NHiPr to give 218

Figure 211 ndash POV-Ray drawing of 218

38

In light of recent findings121 a postulated mechanism implies that after reduction of the aromatic

ring B(C6F5)3 activates the C-F bond provoking nucleophilic addition of hydride from a

[HB(C6F5)3]- anion and liberating B(C6F5)3 for further reactivity Interaction of B(C6F5)3 with C-

F bonds were spectroscopically observed in a 11 combination of B(C6F5)3 and CF3-subtituted

anilines In this respect separate combinations of ortho- or para-F3CPhNH(iPr) and B(C6F5)3 in

C6D5Br gave a 19F NMR spectrum showing four broad resonances with a para-meta gap of 86

ppm and a diagnostic broad singlet assignable to a B-F resonance at -1800 ppm The broad

nature of these resonances and absence of a boron resonance in the 11B NMR spectrum do not

indicate formal C-F bond cleavage rather the data supports reversible B(C6F5)3-CF3

interaction121

2242 Methoxy-substituted rings and C-O bond transformations

Reactivity of FLP systems with oxygen-based substituents is noticeably limited due to high

oxophilicity of electrophilic boranes72 171 However recent findings have been reported on

lability of B-O adducts Stephan et al reported that the ethereal oxygen of the borane-oxyborate

(C6F5)2BCH(C6F5)OB(C6F5)3 derived from the reaction of FLPs with syn-gas activates H2 with

the B(C6F5)2 fragment117 Furthermore Et2O effects H2 activation with B(C6F5)3 and was shown

to be an efficient catalyst in the hydrogenation of olefins257 In an effort to further explore the

scope of the presented metal-free aromatic reductions the arene hydrogenation of anilines with

methoxy substituents was attempted

The combined toluene solution of B(C6F5)3 and the para-methoxy substituted imine (p-

CH3OC6H4)N=CCH3Ph was pressurized with H2 (4 atm) and heated at 110 degC for 48 h This

resulted in the formation of a new white crystalline product assigned to

[(C6H10)NHCH(CH3)Ph][HB(C6F5)3] 219 isolated in 30 yield (Scheme 210) Indeed the 1H

NMR spectrum indicated consumption of N-bound aromatic resonances concomitant with the

appearance of two inequivalent doublet of doublets observed at 447 and 374 ppm with the

corresponding 13C1H NMR resonances observed at 652 and 647 ppm respectively These

peaks are assignable to two inequivalent bridgehead CH groups of the resulting bicyclic

ammonium cation The 11B and 19F NMR spectra were in accordance with the presence of

[HB(C6F5)3]- as the anion X-ray diffraction studies further confirmed the bicyclic structure of

the product and the identity of the anion (Figure 212)

39

Scheme 210 ndash Reaction of (p-CH3OC6H4)N=CCH3Ph and B(C6F5)3 with H2 to give 219


In an effort to appreciate the importance of the position of the methoxy substituent on the arene

ring the separate reactions of ortho- and meta-methoxy substituted (CH3OC6H4)NHCH(CH3)Ph

with B(C6F5)3 were attempted under the established hydrogenationtransannulation protocol In

both cases hydrogenation of the N-bound phenyl group was observed although no

transannulation was achieved The amine (o-CH3OC6H4)NHCH(CH3)Ph gave cis and trans

mixtures of [(2-CH3OC6H10)NH2CH(CH3)Ph][HB(C6F5)3] 220 isolated in 92 yield In contrast

to fluorine abstraction from the ortho carbon position shown in Scheme 28 the methoxy

substituent in this case is not abstracted from the reduced ring due to steric effects preventing

B(C6F5)3 from binding to the substituent However the meta-substituted analogue resulted in C-

O bond cleavage yielding [(C6H11)NH2CH(CH3)Ph][HB(C6F5)3] 212 in 65 isolated yield

(Scheme 211) Ring closure was not obtained for this particular case due to ring strain of the

anticipated product Crystals of 220 suitable for X-ray crystallography were obtained and shown

in Figure 213

40

HB(C6F5)3

NH

OCH3

B(C6F5)3

Ph

+ CH3OH

NH2

OCH3

Ph

NH2Ph

HB(C6F5)3

NHPh

OCH3

220

212

H2

B(C6F5)3

H2

Scheme 211 ndash Synthesis of 220 and 212

Figure 213 ndash POV-Ray drawing of trans-220

In the case of the para-methoxy substituted imine B(C6F5)3 has participated in tandem arene

hydrogenation and transannulation to ultimately afford a 7-azabicyclo[221]heptane derivative a

bicyclic substructure of biological importance258 Unfortunately further expansion of the

substrate scope was not successful giving only the H2 activation product or arene hydrogenation

Such substrate examples include para-methoxyanilines with a methyl substituent at either the

ortho or meta position other para substituents such as HCF2O PhO2S and Br tertiary amine 4-

methoxy-N-phenyl-N-(1-phenylethyl)aniline

22421 Mechanistic studies for C-O and B-O bond cleavage

Studying the mechanism to form the 7-azabicyclo[221]heptane ammonium hydridoborate salt

219 the possibility of an intra- or intermolecular protonation of the methoxy group was initially

41

disproved by heating a toluene sample of the independently synthesized ammonium borate salt

trans-[(4-CH3OC6H10)NH2CH(CH3)Ph][B(C6F5)4] 221a at 110 degC (Scheme 212) No reaction

was evidenced by 1H 11B and 19F NMR spectroscopy However similar treatment of trans-[(4-

CH3OC6H10)NH2CH(CH3)Ph][HB(C6F5)3] 221b at 110 degC prompted release of H2 as evidenced

by the 1H NMR signal at 45 ppm eventually giving compound 219 after 12 h at 110 degC

(Scheme 212)


= C6F5 221a and X = H 221b)

To verify the liberation of CH3OH in the presented reactions the synthesis of 219 was repeated

starting from the free amine trans-[(4-CH3OC6H10)NHCH(CH3)Ph and B(C6F5)3 under H2

(Figure 214 a) After one week at RT the volatiles were transferred under vacuum from the

reaction vessel into a J-Young tube and the 1H NMR spectrum showed evidence of CH3OH

although a yield was not obtained

42



tol (c)

This observation implies that ring closing to yield the 7-azabicyclo[221]heptane ammonium

cation does not proceed by intra- or intermolecular protonation of the methoxy group rather

transannulation proceeds via intramolecular nucleophilic attack of the para-carbon by the amine

nitrogen while B(C6F5)3 captures the methoxide fragment To further support this proposed

mechanism the independently synthesized amine trans-(4-CH3OC6H10)NHiPr was treated with

an equivalent of B(C6F5)3 in the absence of H2 (Scheme 213) Interestingly after heating for 2 h

the reaction resulted in quantitative formation of a new product 222 with a sharp 11B resonance

at -242 ppm and 19F resonances at -1354 -1626 and -1668 ppm consistent with the formation

of the borane-methoxide anion [CH3OB(C6F5)3]- The 1H NMR data signified formation of the

diagnostic bridgehead CH protons at 413 ppm The combination of NMR spectroscopy

elemental analysis and X-ray diffraction studies evidenced the formation of compound 222 as

the bicyclic salt [(C6H10)NHiPr][CH3OB(C6F5)3] (Figure 215)

a)

b)

c)

43


Heating 222 at 110 degC in the absence of H2 eventually results in CH3OH liberation and rapid

degradation of the borane to CH3OB(C6F5)2 and C6F5H In the presence of H2 however 222 is

transformed to 223 with the liberation of CH3OH (Scheme 213) This observation implies that

the ammonium cation of 222 protonates the methoxide bound to boron liberating methanol and

regenerating B(C6F5)3 which undergoes FLP type H2 activation with the bicyclic amine

generating 223 Compound 223 was also prepared from the aniline p-CH3OC6H4NHiPr The

liberated CH3OH was isolated although not quantified and observed by 1H NMR spectroscopy

(Figure 214 b) Interestingly a similar protonation pathway has been previously proposed in a

study by Ashley and OrsquoHare whereby the stoichiometric hydrogenation of CO2 using 2266-

tetramethylpiperidine (TMP) and B(C6F5)3 was reported The authors proposed B-O bond

cleavage of [CH3OB(C6F5)3]- to occur through protonation by the 2266-

tetramethylpiperidinium counter cation259 Additionally most recently Ashley et al proposed

the metal-free carbonyl reduction of aldehydes to possibly proceed through oxonium protonation

of the boron-alkoxide anion [ROB(C6F5)3]-260

Scheme 213 ndash Thermolysis of trans-(4-CH3OC6H10)NHiPr and B(C6F5)3

44

Despite evidence for the protonation pathway contribution by a second pathway involving the

[CH3OB(C6F5)3]- anion and B(C6F5)3 acting as a FLP to activate H2 cannot be disregarded In

this respect a toluene solution of [NEt4][CH3OB(C6F5)3] and 5 mol B(C6F5)3 were exposed to

H2 (4 atm) at 110 degC After heating for 2 h the 11B and 19F NMR spectra revealed complete

consumption of the [CH3OB(C6F5)3]- anion along with emergence of peaks corresponding to the

H2 activation product [NEt4][HB(C6F5)3] and CH3OH (Scheme 214) This latter mechanism

provides an alternative path to the anion of 223 This type of system draws analogy to H2

activation by the earlier mentioned BO FLP (C6F5)2BCH(C6F5)OB(C6F5)3 suggesting H2

cleavage gives protonated oxygen and borohydride117

Gradual decomposition of the borane catalyst due to CH3OH was also observed as the amine is

not present to displace CH3OH from B(C6F5)3 consequently hindering its decomposition The

pKa of hydroxylic substrates have been shown to be significantly activated by coordination to

B(C6F5)3 generating strong Broslashnsted acids with pKa values comparable with HCl (84 in

acetonitrile)261

Scheme 214 ndash H2 activation between [CH3OB(C6F5)3]- anion and B(C6F5)3

Collectively it may be read that compound 219 is formed by initial hydrogenation of the imine

(p-CH3OC6H4)N=CCH3Ph C=N double bond followed by reduction of the arene ring affording

the cyclohexylamine The amine and borane can activate H2 to give the ammonium salt albeit at

elevated temperatures this is reversible allowing the borane to activate the methoxy substituent

and induce transannulation effecting C-O bond cleavage (Scheme 215) Subsequent conversion

of the generated methoxy-borate anion to the hydridoborate anion proceeds under H2 following

the pathways presented in Schemes 213 and 214

45

NH2

R

OCH3

110 oC

NHR

OCH3

NHR

OCH3

(F5C6)3B

+ H2

B(C6F5)3

H2

HB(C6F5)3

- H2HN

R

CH3OB(C6F5)3

+ H2

HB(C6F5)3

HNR

- CH3OH

Scheme 215 ndash Overall proposed mechanism for the formation of 7-azabicyclo[221] heptane

225 Aromatic hydrogenation of N-heterocyclic compounds

While seeking to extend the scope of aromatic reductions attention was focused on a series of

mono- and di-substituted pyridines quinolines and several other N-heterocycles In this regard

the aromatic hydrogenation of a variety of N-based heterocycles was explored using

stoichiometric combinations of B(C6F5)3 in the presence of H2 (4 atm)

2251 Hydrogenation of substituted pyridines

Detailed studies on the effects of increased steric bulk on pyridine249 and their reactivity with

B(C6F5)3 to activate H2248 at room temperature have been previously reported Stoichiometric

combination of the Lewis base 26-diphenylpyridine and the Lewis acid B(C6F5)3 do not show

evidence of a donor-acceptor interaction by NMR spectroscopy in contrast a reversible adduct is

observed with 26-lutidine Exposure of either combination of 26-diphenylpyridine or 26-

lutidine and B(C6F5)3 under H2 (4 atm) at room temperature activate H2 affording the

corresponding pyridinium hydridoborate salts

Nonetheless heating a mixture of 26-diphenylpyridine and B(C6F5)3 under H2 (4 atm) at 115 degC

for 16 h gives a new product isolated in 92 yield (Table 22 entry 1) The 11B NMR data in

CD2Cl2 displayed a doublet at -246 ppm and three resonances in the 19F NMR spectrum

observed at -1340 -1634 and -1666 ppm confirmed the presence of the [HB(C6F5)3]- anion

The 1H NMR spectrum showed a broad singlet at 590 ppm attributable to the NH2 group

multiplets at 453 and 226 - 189 ppm in addition to signals assignable to the phenyl and BH

46

groups These data were consistent with the formulation of the salt [26-

Ph2C5H8NH2][HB(C6F5)3] 224 Furthermore the 1H NMR data revealed a de of 91 favouring

the meso-diastereomer an assignment that was confirmed via NMR spectroscopy and the

molecular structure shown in Figure 216 (left) In a similar fashion the reaction of 26-lutidine

with B(C6F5)3 under H2 at 115 degC for 60 h afforded the corresponding salt [26-

Me2C5H8NH2][HB(C6F5)3] 225 in 84 yield (Table 22 entry 1) with a de of 80 also

favouring the meso-diastereomer (Figure 216 right) The preferred diastereoselectivity is

consistent with the known ability of B(C6F5)3 to effect epimerization of chiral carbon centres

adjacent to nitrogen by a process previously described to involve hydride abstraction and

redelivery262

Figure 216 ndash POV-Ray drawing of 224 (left) and 225 (right)

The substrate ethyl 2-picolinate was exposed to the hydrogenation conditions giving a B(C6F5)3

adduct of the reduced substrate (2-(EtOCO)C5H9NH)B(C6F5)3 226 isolated in 74 yield after

36 h (Table 22 entry 2) The 11B NMR spectrum in CD2Cl2 showed a broad singlet at -486 ppm

and 15 inequivalent 19F resonances which were consistent with adduct formation between the

boron and nitrogen centres inhibiting rotation about the bond

47

Table 22 ndash Hydrogenation of substituted pyridines

Multinuclear NMR spectra of 226 displayed the presence of two diastereomers in a 11 ratio

Most distinguishable were the 13C1H resonances at 1674 and 1712 ppm attributable to the

OCO-ester groups and the 1H NMR signals at 418 and 424 ppm arising from the methine

protons Furthermore 1H1H NOESY experiments confirmed the assignment of these peaks to

the respective RSSR and RRSS diastereomers Independent reaction of B(C6F5)3 with the

optically pure piperidine S-2-(EtOCO)C5H9NH at -30 degC in CD2Cl2 afforded the preferential

formation of the SS-diastereomer of 226 However on warming to room temperature over 18 h

racemization at nitrogen eventually afforded a 11 mixture of the SS and SR diastereomers

Even though the pyridine-borane adduct of 2-phenylpyridine has been isolated and characterized

this adduct is reversed at 115 degC Reduction of the substrate using B(C6F5)3 and H2 gave a

mixture of two products isolated in 54 overall yield after 48 h (Table 22 entry 3) A broad 11B

NMR signal at -391 ppm together with a doublet at -240 ppm were consistent with the

48

presence of the adduct (2-PhC5H9NH)B(C6F5)3 227a and the ionic pair [2-

PhC5H9NH2][HB(C6F5)3] 227b in a 41 ratio respectively

The formulation of 227a is further supported by NMR data revealing two distinctively broad

NH singlets in the 1H NMR spectrum at 555 and 581 ppm attributable to a 71 ratio of the

RSSR and RRSS diastereomers The RSSR diastereomer was the more abundant form as

evidenced by NMR and X-ray crystallographic data (Figure 217)

Figure 217 ndash POV-Ray depiction of 227a B-N 1662(2) Aring

Interestingly the preferential formation of this diastereomer was evidenced by 1H19F HOESY

NMR spectroscopy through intramolecular π-π stacking interactions of the Ph and C6F5 groups

in addition to interactions between the C-H and N-H groups of piperidine and ortho-fluoro

groups of B(C6F5)3 (Figure 218) Identity of compound 227b was confirmed based on

agreement of spectral parameters with the NH2 methine and methylene groups

49


cross peaks between Ph-piperidine (1H δ 415 CH 555 NH 720 Ph) and o-C6F5 groups

The presence of adduct 227a raised the question about dissociation of the B-N bond and

possible participation of the liberated borane in further pyridine hydrogenation To probe this a

toluene solution of 2-phenylpyridine and 10 mol of 227 was exposed to H2 (4 atm) at 110 degC

After heating for 24 h 1H NMR spectroscopy did not indicate consumption of the pyridine

reagent Similarly repeating the hydrogenation of 2-phenylpyridine with 10 mol B(C6F5)3 did

not result in catalysis

2252 Hydrogenation of substituted N-heterocycles

Attempting to extend the aromatic hydrogenation of N-heterocycles beyond pyridine substrates

attention was focused to 1234-tetrahydroquinoline derivatives which have been reported to

result from the catalytic hydrogenation of N-heterocycles98 In examining the structure of

tetrahydroquinoline the carbocyclic ring fused to the N-heterocycle was observed to be similar

to a secondary aniline (Figure 219) Thus emerging the avenues of previous reports on catalytic

hydrogenation of substituted quinolines and most recent findings on the stoichiometric reduction

of anilines the complete homogeneous hydrogenation of N-heteroaromatic compounds was

explored

Figure 219 ndash 1234-Tetrahydroquinoline with emphasis on the fused carbocyclic ring

50

Exposure of 2-methylquinoline and B(C6F5)3 to H2 (4 atm) at 115 degC for 48 h was found to effect

hydrogenation of not only the N-heterocycle but also the carbocyclic ring to yield [2-

MeC9H15NH2][HB(C6F5)3] 228 in 67 (Table 23 entry 1) In a similar fashion both rings of 2-

phenylquinoline were reduced in the same time frame to give [2-PhC9H15NH2][HB(C6F5)3] 229

in 95 yield (Table 23 entry 1)

The 1H NMR spectra for 228 and 229 exhibited characteristic chemical shifts corresponding to

NH2 methine and methylene groups Both compounds 228 and 229 were produced as mixtures

of diastereomers although in both cases the major isomer was crystallized and found to comprise

of 60 and 73 of the isolated products respectively The molecular structures show both

compounds exhibit SSSRRR stereochemistries in which one of the ring junctions adopts an

equatorial disposition while the other is axially disposed (Figure 220 a and b) Analogous

treatment of 8-methylquinoline with H2 and B(C6F5)3 in toluene for 48 h yielded [8-

MeC9H15NH2][HB(C6F5)3] 230 in 76 (Table 23 entry 1) 1H and 13C1H NMR data suggest

only the presence of the RRRSSS diastereomers (Figure 220 c)

Figure 220 ndash POV-Ray depiction of the cations for compounds 228 (a) 229 (b) and 230 (c)

a) b) c)

51

Table 23 ndash Hydrogenation of substituted N-heterocycles

The corresponding reduction of acridine results in isolation of the fully reduced tricyclic species

in 76 yield (Table 23 entry 2) The isolated product is obtained as a mixture of two isomers

one of which was characterized crystallographically as the salt [C13H22NH2][HB(C6F5)3] 231a

As shown in Figure 221 all ring junctions are equatorially positioned and thus the SRSRRSRS

diastereomers are assigned

Figure 221 ndash POV-Ray depiction of the cation for compound 231a

52

Interestingly a second product was isolated from the pentane work-up crystallographic data

showed it to be the adduct (C13H22NH)B(C6F5)3 231b (Figure 222) In this case however the

stereochemistries of the ring junctions adjacent to nitrogen are inverted affording the RRSSSSRR

diastereomers of the reduced acridine heterocycle Compound 231b was also independently

synthesized in 73 yield from a mixture of isomers of the neutral amine C13H22NH and

B(C6F5)3

Figure 222 ndash POV-Ray depiction of 231b B-N 1666(2) Aring

Although the substrates 23-dimethyl and 23-diphenylquinoxaline have two Lewis basic

nitrogen centres the reduction reactions required only one equivalent of B(C6F5)3 yielding the

piperazinium derivatives [23-(C4H6Me)2NHNH2][HB(C6F5)3] 232 and [23-

(C4H6Ph)2NHNH2][HB(C6F5)3] 233 in 59 and 55 yield respectively (Table 23 entry 3) In

the case of 232 a single set of diastereomers was observed and the NMR data were consistent

with ring junctions and methyl groups adopting equatorial dispositions In contrast the isolated

product 233 comprised of two diastereomers Crystallographic characterization of one

diastereomer showed the phenyl rings adopt equatorial positions while the ring junctions are

axial and equatorially disposed (Figure 223)

Figure 223 ndash POV-Ray depiction of the cation for compound 233

53

It is noteworthy that while the aromatic ring of the quinoxaline fragment is fully reduced the

phenyl substituents remain intact In a similar situation reduction of 78-benzoquinoline resulted

in the formation of [(C6H4)C7H12NH2][HB(C6F5)3] 234 in 55 yield (Table 23 entry 4) 1H

NMR spectroscopy evidenced a 41 mixture of two diastereomers in which reduction of the

pyridyl and adjacent carbocyclic ring were achieved while aromaticity of the ring remote from

the nitrogen atom was retained X-ray crystallography unambiguously confirmed the dominant

diastereomer 234a to have SRRS stereochemistry while the less abundant diastereomer 234b

showed SSRR stereochemistry (Figure 224)

Figure 224 ndash POV-Ray depiction of the cations for compounds 234a (left) and 234b (right)

Efforts to reduce the related heterocycle 110-phenanthroline in which a pyridyl ring is fused at

the 7 and 8 position of quinoline were undertaken employing one equivalent of B(C6F5)3 After

heating the solution for 14 h at 115 degC under H2 (4 atm) 1H NMR spectroscopy indicated

complete hydrogenation of the N-heterocycle in addition to loss of C6F5H and formation of a

four-coordinate boron centre with a 11B resonance observed at 302 ppm The [HB(C6F5)3]- anion

was not observed and further heating did not reveal hydrogenation of the carbocyclic ring

A second equivalent of B(C6F5)3 was added and the reaction was re-exposed to H2 (4 atm) for a

total of 96 h at 115 degC This resulted in isolation of [(C5H3N)(CH2)2(C5H8NH)B(C6F5)2]

[HB(C6F5)3] 235 in 73 yield (Table 23 entry 5) The 11B NMR spectrum revealed the

presence of two four-coordinate boron centres with resonances at 302 and -254 ppm The

former boron species exhibited six inequivalent fluorine atoms evidenced by 19F NMR

spectroscopy inferring the presence of two inequivalent fluoroarene rings where steric

congestion is inhibiting ring rotation at the B-N and B-C bonds The latter 11B NMR signal

together with the three corresponding 19F resonances arise from the [HB(C6F5)3]- anion X-ray

crystallography confirmed the formulation of 235 as the SRSRSR diastereomer present as 65

of the isolated reaction mixture (Figure 225)

54



N(2) pyridine

In the cationic fragment of compound 235 the boron centre is bound to two perfluoroarene rings

and is chelated by the pyridine and amine nitrogen atoms of partially reduced 110-

phenanthroline The B-N distances in the cation were found for B(1)-N(1)amine to be 1615(3) and

B(1)-N(2)pyridine 1598(3) Aring In this unique case as reduction of the heterocycle proceeds a

single pyridyl ring is initially reduced in which the resulting amine coordinates B(C6F5)3

resulting in loss of C6F5H and chelation of B(C6F5)2 by the pyridyl nitrogen centre affording the

cation (Scheme 216) The second equivalent of the borane remains intact and partakes in partial

hydrogenation of the carbocyclic ring Elimination of C6F5H followed by ring closure is

thermodynamically favoured due to formation of the five-membered borocycle

NN NN

B

B(C6F5)3

(C6F5)3B H

- C6F5H H2

235

(C6F5)2

Scheme 216 ndash Proposed reaction pathway for the formation of 235

Although this arene hydrogenation method is applicable to the presented N-heteroaromatic

substrates the reactivity was not successfully extended to 46-dimethyl-1-phenylpyrimidin-

2(1H)-one 2-methylindoline 3-methylindole 1-methylisoquinoline and carbazole

55

2253 Proposed mechanism for aromatic hydrogenation

The reductions described demonstrate the ability of B(C6F5)3 to mediate the complete aromatic

hydrogenation of a number of N-heterocycles It is clear that the products arise from reduction of

pyridyl andor aniline-type rings and in some cases affording a preferred set of diastereomers as

demonstrated by the ability of B(C6F5)3 to epimerize chiral centers alpha to nitrogen262 Efforts

to monitor several of the mixtures over the course of the reactions failed to provide unambiguous

mechanistic insight By analogy to computational studies presented for aniline hydrogenations

the need for elevated temperatures presumably reflects the fact that hybridizing the para-carbon

of the N-heterocycle is energetically uphill however once this is achieved there is an exothermic

route to the saturated amine Subsequent activation of H2 by the reduced amine and borane

affords the corresponding ammonium salt which is irreversible under the reaction conditions

thus precluding catalytic reduction This could simply be explained by Broslashnsted basicity of the

nitrogen centre An sp2 hybridized nitrogen has the lone pair in a p-orbital therefore it can

participate in resonance making it less basic as opposed to sp3 hybridization which does not have

a p-orbital (pyridine pKa 52 quinoline pKa 492 piperidine pKa 112 all values are in H2O)

While the reactions are nominally stoichiometric multiple turnovers of H2 activation are

achieved For example eight equivalents of H2 are taken up by acridine in the formation of 231

2254 Approaches to dehydrogenation

Although hydrogenation of aromatic substrates is appealing the reversible reaction

dehydrogenation of the products with aim at obtaining a molecular dihydrogen storage device

became a topic of interest Heating compound 231 at 115 degC in a vacuum sealed J-Young tube

did not evolve H2 As an alternative approach the neutral amine C13H22NH was combined with

the electrophilic boranes B(C6F5)3 B(p-C6F4H)3 or (12-C12F9)B(C6F5)2 and heated under

vacuum After 24 h trace amounts of aromatic resonances corresponding to dehydrogenation of

the N-heterocycle and a single carbocyclic ring (five equivalents of H2) was observed by 1H

NMR spectroscopy It is important to note that this process did not liberate H2 rather amine and

B(C6F5)3 abstracted proton and hydride respectively regenerating 231 One can envision this

dehydrogenation process could possibly be applied to transfer hydrogenation of imines similar

to an earlier report by the Stephan group262

56

23 Conclusions

This chapter provides an account on the discovery of N-phenyl amine reductions under H2 using

an equivalent of B(C6F5)3 to yield the corresponding cyclohexylamine derivatives In these

reactions B(C6F5)3 mediates uptake of four equivalents of H2 terminating with a final FLP

activation of H2 affording the cyclohexylammonium salts A possible reaction pathway is

proposed based on experimental evidence and theoretical calculations The substrate scope is

extended to a variety of pyridyl- and aniline-type rings of N-heterocyclic compounds These

reductions represent the first example of homogeneous metal-free hydrogenation of aromatic

rings

Shortly after publishing the presented data on aromatic hydrogenations in two separate reports

the Stephan group communicated the partial reduction of polycyclic aromatic hydrocarbons

using catalysts derived from weakly basic phosphines263 or ethers257 with B(C6F5)3 Additionally

the Du group showed a borane catalyzed route to the stereoselective hydrogenation of

pyridines264

24 Experimental Section

241 General considerations

All manipulations were performed under an atmosphere of dry oxygen-free N2 by means of both

standard Schlenk line or glovebox techniques (MBraun glovebox equipped with a -30 degC

freezer) Pentane hexane tetrahydrofuran dichloromethane and toluene (Sigma Aldrich) were

dried employing a Grubbs-type column system (Innovative Technology) degassed and stored

over molecular sieves (4 Aring) in the glovebox Bromobenzene (-H5 and -D5) were purchased from

Sigma Aldrich and dried over CaH2 for several days and vacuum distilled onto 4 Aring molecular

sieves prior to use Dichloromethane-d2 was purchased from Sigma Aldrich dried over CaH2 and

vacuum distilled onto 4 Aring molecular sieves prior to use Tetrahydrofuran-d8 and toluene-d8 were

purchased from Sigma Aldrich and distilled over sodiumbenzophenone prior to use Molecular

sieves (4 Aring) were purchased from Sigma Aldrich and dried at 140 ordmC under vacuum for 24 h

prior to use B(C6F5)3 was purchased from Boulder Scientific and sublimed at 80 degC under high

vacuum before use Sodium methoxide and tetraethylammonium chloride were purchased from

Sigma Aldrich and dried under vacuum at 140 ordmC for 12 h prior to use

57

All substituted amines anilines quinolines pyridines and other N-heterocycles were purchased

from Sigma Aldrich Alfa Aesar or TCI Potassium tetrakis(pentafluorophenyl)borate and

hydrogen chloride (40 M in 14-dioxane) were purchased from Alfa Aesar The oils were

distilled over CaH2 and solids were sublimed under high vacuum prior to use The following

compounds were independently synthesized following the cited procedure265 unless indicated

otherwise N-tert-butylaniline266 NN-(14-phenylenebis(methylene))bis(tert-butylamine) N-

isopropyl-2-methylaniline N-isopropyl-4-methylaniline N-isopropyl-4-methoxyaniline N-

isopropyl-3-methylaniline N-isopropyl-35-dimethylaniline N-(1-phenylethylidene)aniline

N1N4-di(propan-2-ylidene)benzene-14-diamine 44-methylenebis(N-isopropylaniline) 2-

fluoro-N-isopropylaniline 3-fluoro-N-isopropylaniline 4-fluoro-N-isopropylaniline 4-methoxy-

N-(1-phenylethylidene)aniline 2-methoxy-N-(1-phenylethyl)aniline266 3-methoxy-N-(1-

phenylethyl)aniline266 and alkylation methods267 to prepare trans-(4-

CH3OC6H10)NHCH(CH3)Ph and trans-(4-CH3OC6H10)NHiPr

Nuclear magnetic resonance (NMR) spectroscopy spectra were recorded on a Bruker Avance III

400 MHz Varian 400 MHz spectrometer equipped with an HFX AutoX triple resonance indirect

probe (used for 13C1H 19F experiments) or an Agilent DD2 500 MHz spectrometer Spectra

were referenced to residual solvent of C6D5Br (1H = 728 ppm for meta proton 13C = 1224 ppm

for ipso carbon) CD2Cl2 (1H = 532 ppm 13C = 5384 ppm) d8-tol (1H = 208 ppm for CH3 13C

= 13748 ppm for ipso carbon) d8-THF (1H = 358 ppm for OCH2 13C = 6721 ppm for OCH2)

or externally (11B (Et2O)BF3 19F CFCl3) Chemical Shifts (δ) are reported in ppm and the

absolute values of the coupling constants (J) are in Hz NMR assignments are supported by 2D

and DEPT-135 experiments

Elemental analyses (C H N) were performed in-house employing a Perkin Elmer 2400 Series II

CHNS Analyzer H2 (grade 50) was purchased from Linde and dried through a Nanochem

Weldassure purifier column prior to use High resolution mass spectra (HRMS) were obtained

using an ABSciex QStar Mass Spectrometer with an ESI source MSMS and accurate mass

capabilities

242 Synthesis of compounds

Synthesis of [NEt4][CH3OB(C6F5)3] In the glove box a 4 dram vial equipped with a stir bar

was charged with a solution of B(C6F5)3 (100 mg 0195 mmol) in CH2Cl2 (10 mL) To the vial

58

Na OCH3 (105 mg 0195 mmol) was added and the reaction was allowed to mix for 3 h at RT

The salt Na CH3OB(C6F5)3 was isolated as a white solid and dried under vacuum (110 mg 0195

mmol gt99) Na CH3OB(C6F5)3 (110 mg 0195 mmol) in CH2Cl2 (10 mL) was subsequently

added to a 4 dram vial containing NEt4 Cl (323 mg 0195 mmol) in CH2Cl2 (5 mL) The

reaction was allowed to mix at RT for 16 h and filtered through Celite The filtrate was

concentrated and placed in a -30 degC freezer giving the product as colourless needles (125 mg

0186 mmol 95)

1H NMR (400 MHz CD2Cl2) δ 322 (q 3JH-H = 73 Hz 8H Et) 311 (s 3H OCH3) 142 (tm 3JH-H = 73 Hz 12H Et) 19F NMR (377 MHz CD2Cl2) δ -1344 (m 3JF-F = 20 Hz 2F o-C6F5)

-1636 (t 3JF-F = 20 Hz 1F p-C6F5) -1667 (m 2F m-C6F5) 11B NMR (128 MHz C6D5Br) δ -

256 (s BOCH3) 13C1H NMR (101 MHz CD2Cl2) δ 1480 (dm 1JC-F = 240 Hz CF) 1380

(dm 1JC-F = 244 Hz CF) 1364 (dm 1JC-F = 248 Hz CF) 1246 (br ipso-C6F5) 529 (Et) 519

(OCH3) 710 (Et) Elemental analysis was not successful after numerous attempts

Synthesis of [tBuNH2Ph][HB(C6F5)3] (21) In the glove box a 100 mL Teflon screw cap

Schlenk tube equipped with a stir bar was charged with a yellow solution of B(C6F5)3 (100 mg

0195 mmol) in pentane (7 mL) To the reaction tube N-tert-butylaniline (291 mg 0195 mmol)

was added immediately resulting in a pale orange cloudy solution The reaction tube was

degassed three times through a freeze-pump-thaw cycle on the vacuumH2 line and filled with H2

(4 atm) at -196 ordmC After about 10 min of reaction time at RT white precipitate was observed in

the reaction vessel and the solution became colourless The tube was left to stir at RT for 12 h

The solvent was decanted and the white precipitate was washed with pentane (3 mL) dried under

vacuum and isolated (106 mg 0160 mmol 82)

1H NMR (400 MHz C6D5Br) δ 715 (br s 2H NH2) 712 (t 3JH-H = 73 Hz 1H p-Ph) 706 (t 3JH-H = 73 Hz 2H m-Ph) 682 (d 3JH-H = 76 Hz 2H o-Ph) 369 (br q 1JB-H = 78 Hz 1H BH)

102 (s 9H tBu) 19F NMR (377 MHz C6D5Br) δ -1335 (br 2F o-C6F5) -1613 (br 1F p-

C6F5) -1650 (br 2F m-C6F5) 11B NMR (128 MHz C6D5Br) δ -240 (d 1JB-H = 78 Hz BH)

13C1H NMR (101 MHz C6D5Br) δ 1494 (dm 1JC-F = 238 Hz CF) 1382 (dm 1JC-F = 244

Hz CF) 1369 (dm 1JC-F = 247 Hz CF) 1309 (p-Ph) 1299 (m-Ph) 1237 (o-Ph) 1244 (ipso-

C6F5) 659 (tBu) 255 (tBu) (ipso-Ph was not observed) Anal calcd () for C28H17BF15N C

5071 H 258 N 211 Found C 5027 H 287 N 219

59

[tBuNHDPh][DB(C6F5)3] (21-d2) This compound was prepared similar to 21 using D2

19F NMR (377 MHz C6H5Br) δ -1332 (m 2F o-C6F5) -1609 (br 1F p-C6F5) -1646 (m 2F

m-C6F5) 11B NMR (128 MHz C6H5Br) δ -238 (s BD)

Synthesis of [14-C6H4(CH2NH2tBu)2][HB(C6F5)3]2 (22) In a glove box a 100 mL Teflon

screw cap Schlenk tube equipped with a stir bar was charged with a solution of B(C6F5)3 (304

mg 0594 mmol) and NN-(14-phenylenebis(methylene))bis(tert-butylamine) (725 mg 0297

mmol) in toluene (4 mL) The reaction was degassed three times with a freeze-pump-thaw cycle

on the vacuumH2 line The reaction flask was cooled to -196 ordmC and filled with H2 (4 atm)

Immediate precipitation of a white solid was observed at RT The reaction mixture was stirred

overnight at 70 ordmC Pentane (10 mL) was added after which the supernatant was decanted The

residue was washed with pentane (5 mL) and dried in vacuo to give the product as a white

powder (374 mg 0297 mmol gt99)

1H NMR (400 MHz CD2Cl2) δ 727 (s 4H Ph) 595 (br s 4H NH2) 438 (s 4H CH2) 339

(br q 1JB-H = 83 Hz 2H BH) 162 (s 18H tBu) 19F NMR (377 MHz CD2Cl2) δ -1349 (m 3JF-F = 21 Hz 2F o-C6F5) -1635 (t 3JF-F = 21 Hz 1F p-C6F5) -1670 (m 2F m-C6F5) 11B

NMR (128 MHz CD2Cl2) δ -243 (d 1JB-H = 83 Hz BH) 13C1H NMR (101 MHz d8-THF )

δ 1493 (dm 1JC-F = 236 Hz CF) 1461 (quaternary C for C6H4) 1385 (dm 1JC-F = 243 Hz CF)

1374 (dm 1JC-F = 246 Hz CF) 1345 (br ipso-C6F5) 1314 (Ph) 595 (tBu) 461 (CH2) 259

(tBu) Anal calcd () for C51H30B2F30N2 C 4852 H 240 N 222 Found C 4882 H 269 N

252

Compounds 23 ndash 214 were prepared following a common procedure In the glove box a 25 mL

Teflon screw cap Schlenk tube equipped with a stir bar was charged with a yellow solution of

B(C6F5)3 (379 mg 740 μmol) and N-phenyl amine (740 μmol) in toluene (2 mL) The reaction

tube was degassed three times through a freeze-pump-thaw cycle on the vacuumH2 line and

filled with H2 (4 atm) at -196 ordmC After the addition of H2 the reaction tube was placed in a 110

ordmC oil bath After the appropriate reaction time the toluene was removed under reduced pressure

resulting in crude pale yellow oil The oil was washed with pentane (6 mL) affording the product

as a white powder

60

[tBuNH2Cy][HB(C6F5)3] (23) N-tert-butylaniline (110 mg 740 μmol) reaction time 48 h

product (415 mg 620 μmol 84)

1H NMR (400 MHz C6D5Br) δ 507 (br 2H NH2) 355 (br q 1JB-H = 83 Hz 1H BH) 272 (m

1H N-Cy) 155 (m 2H Cy) 145 (m 2H Cy) 131 (m 1H Cy) 117 (m 3H Cy) 091 (s 9H

tBu) 090 (m 2H Cy) 19F NMR (377 MHz C6D5Br) δ -1327 (m 3JF-F = 21 Hz 2F o-C6F5)

1607 (t 3JF-F = 21 Hz 1F p-C6F5) -1645 (m 2F m-C6F5) 11 B NMR (128 MHz C6D5Br) δ -

240 (d 1JB-H = 83 Hz BH) 13C1H NMR (101 MHz C6D5Br) δ 1483 (dm 1JC-F = 238 Hz

CF) 1382 (dm 1JC-F = 247 Hz CF) 1368 (dm 1JC-F = 247 Hz CF) 1354 (ipso-C6F5) 610

(tBu) 561 (N-Cy) 319 (Cy) 258 (tBu) 244 (Cy) 236 (Cy) Anal calcd () for

C28H23BF15N C 5025 H 346 N 209 Found C 4985 H 357 N 219

Synthesis of PhNHiPrB(C6F5)3 (24rsquo) In a glove box a 20 mL dram vial equipped with a

magnetic stir bar was charged with B(C6F5)3 (176 mg 0344 mmol) and N-isopropylaniline (465

mg 0344 mmol) in toluene (4 mL) All volatiles were removed and the crude oil was washed

with hexane (2 mL) The hexane portion was reduced in volume and placed in a -30 ordmC freezer

Colourless crystals were obtained (122 mg 0192 mmol 55)

1H NMR (400 MHz CD2Cl2 193K) δ 740 - 726 (m 5H Ph) 696 (br 1H NH) 416 (br m

1H iPr) 123 (br 3H iPr) 072 (br 3H iPr) 19F NMR (367 MHz CD2Cl2 193K) δ -1219 (m

1F o-C6F5) -1272 (m 1F o-C6F5) -1279 (m 2F o-C6F5) -1315 (m 1F o-C6F5) -1388 (m

1F o-C6F5) -1543 (t 3JF-F = 21 Hz 1F p-C6F5) -1573 (t 3JF-F = 21 Hz 1F p-C6F5) -1575 (t 3JF-F = 21 Hz 1F p-C6F5) -1618 (m 1F m-C6F5) -1622 (m 1F m-C6F5) -1625 (m 1F m-

C6F5) -1627 (m 1F m-C6F5) -1629 (m 1F m-C6F5) -1636 (m 1F m-C6F5) 11B NMR (128

MHz CD2Cl2 193K) δ -323 (s B-N) 13C1H NMR (101 MHz CD2Cl2 298K) δ 1478 (dm 1JC-F = 246 Hz CF) 1390 (dm 1JC-F = 242 Hz CF) 1365 (dm 1JC-F = 236 Hz CF) 1328

(ipso-Ph) 1301 (o-Ph) 1295 (p-Ph) 1227 (m-Ph) 556 (iPr) 195 (iPr) (ipso-C6F5 was not

observed) Anal calcd () for C27H13BF15N C 5011 H 202 N 216 Found C 4961 H 246

N 209

[iPrNH2Cy][HB(C6F5)3] (24) N-Isopropylaniline (100 mg 740 μmol) reaction time 36 h

product (481 mg 730 μmol 93) Crystals suitable for X-ray diffraction were grown from a

layered dichloromethanepentane solution at -30 ordmC

61

1H NMR (400 MHz C6D5Br) δ 510 (s 2H NH2) 356 (br q 1JB-H = 84 Hz 1H BH) 303 (m 1JH-H = 65 Hz 1H iPr) 276 (m 1H N-Cy) 156 (m 2H Cy) 147 (m 2H Cy) 134 (m 1H

Cy) 099 - 086 (m 5H Cy) 091 (d 1JH-H = 65 Hz 6H iPr) 19F NMR (377 MHz C6D5Br) δ -

1330 (m 3JF-F = 21 Hz 2F o-C6F5) -1609 (t 3JF-F = 21 Hz 1F p-C6F5) -1647 (m 2F m-

C6F5) 11 B NMR (128 MHz C6D5Br) δ -239 (d 1JB-H = 84 Hz BH) 13C1H NMR (101 MHz

C6D5Br) δ 1483 (dm 1JC-F = 238 Hz CF) 1384 (dm 1JC-F = 247 Hz CF) 1369 (dm 1JC-F =

248 Hz CF) 1288 (ipso-C6F5) 567 (N-Cy) 498 (iPr) 294 (Cy) 241 (Cy) 240 (Cy) 189

(iPr) Anal calcd () for C27H21BF15N C 4949 H 323 N 214 Found C 4952 H 345 N

219

[Cy2NH2][HB(C6F5)3] (25) Method 1 N-Cyclohexylaniline (130 mg 740 μmol) reaction

time 36 h product (452 mg 650 μmol 88) Method 2 Diphenylamine (125 mg 740 μmol)

reaction time 96 h product (334 mg 480 μmol 65) Crystals suitable for X-ray diffraction

were grown from a concentrated solution in C6D5Br at RT

1H NMR (400 MHz C6D5Br) δ 498 (br s 2H NH2) 317 (br q 1JB-H = 86 Hz 1H BH) 247

(m 2H N-Cy) 122 (m 4H Cy) 111 (m 4H Cy) 099 (m 2H Cy) 070 - 046 (m 10H Cy)

19F NMR (377 MHz C6D5Br) δ -1332 (m 3JF-F = 20 Hz 2F o-C6F5) -1608 (t 3JF-F = 20 Hz

1F p-C6F5) -1648 (m 2F m-C6F5) 11B NMR (128 MHz C6D5Br) δ -241 (d 1JB-H = 86 Hz

BH) 13C1H NMR (101 MHz C6D5Br) δ 1480 (dm 1JC-F = 241 Hz CF) 1380 (dm 1JC-F =

247 Hz CF) 1365 (dm 1JC-F = 248 Hz CF) 1264 (ipso-C6F5) 558 (N-Cy) 293 (Cy) 238

(Cy) 237 (Cy) Anal calcd () for C30H25BF15N C 5182 H 362 N 201 Found C 5217 H

386 N 212

[iPrNH2(2-MeC6H10)][HB(C6F5)3] (26) N-Isopropyl-2-methylaniline (111 mg 740 μmol)

reaction time 36 h product (398 mg 570 μmol 77) NMR data is reported for one isomer


1H N-Cy) 313 (m 3JH-H = 62 Hz 1H iPr) 180 - 118 (m 9H Cy) 113 (d 3JH-H = 64 Hz

6H iPr) 086 (d 3JH-H = 62 Hz 3H Me) 19F NMR (377 MHz C6D5Br) δ -1337 (m 3JF-F = 21

Hz 2F o-C6F5) -1614 (t 3JF-F = 21 Hz 1F p-C6F5) -1653 (m 2F m-C6F5) 11B NMR (128

MHz C6D5Br) δ -237 (d 1JB-H = 82 Hz BH) 13C1H NMR (101 MHz C6D5Br) partial δ

1485 (dm 1JC-F = 235 Hz CF) 1385 (dm 1JC-F = 246 Hz CF) 1370 (dm 1JC-F = 249 Hz CF)

1236 (ipso-C6F5) 638 (N-Cy) 593 (iPr) 347 (Cy) 319 (Cy) 304 (CMeH) 291 (Cy) 210

62

(Me) 186 (iPr) Anal calcd () for C28H23BF15N C 5025 H 346 N 209 Found C 5021 H

359 N 214

[iPrNH2(4-MeC6H10)][HB(C6F5)3] (27) N-isopropyl-4-methylaniline (111 mg 740 μmol)

reaction time 36 h product (377 mg 540 μmol 73)

1H NMR (400 MHz C6D5Br) δ 553 (br 2H NH2) 371 (br q 1JB-H = 83 Hz 1H BH) 317 (m 3JH-H = 64 Hz 1H iPr) 290 (m 1H N-Cy) 171 (m 2H Cy) 162 (m 2H Cy) 120 (m 3H

Cy) 110 (d 3JH-H = 64 Hz 6H iPr) 086 (d 3JH-H = 66 Hz 3H Me) 077 (m 2H Cy) 19F

NMR (377 MHz C6D5Br) δ -1337 (m 3JF-F = 21 Hz 2F o-C6F5) -1613 (t 3JF-F = 21 Hz 1F

p-C6F5) -1652 (m 2F m-C6F5) 11B NMR (128 MHz C6D5Br) δ -236 (d 1JB-H = 83 Hz BH)


Hz CF) 1367 (dm 1JC-F = 250 Hz CF) 562 (N-Cy) 495 (iPr) 319 (Cy) 304 (CMeH) 291

(Cy) 210 (Me) 186 (iPr) Anal calcd () for C28H23BF15N C 5025 H 346 N 209 Found

C 5014 H 348 N 209

[iPrNH2(4-MeOC6H10)][HB(C6F5)3] (28) N-Isopropyl-4-methoxyaniline (122 mg 740

μmol) reaction time 36 h product (308 mg 450 μmol 61)

1H NMR (400 MHz C6D5Br) δ 553 (br 2H NH2) 371 (br q 1JB-H = 82 Hz 1H BH) 346 (br

4H OMe and CHOMe) 299 (br m 1H N-Cy) 237 (m 1H iPr) 162 (m 2H Cy) 129 (m

2H Cy) 107 (m 4H Cy) 081 (d 3JH-H = 65 Hz 6H iPr) 19F NMR (377 MHz C6D5Br) δ -


C6F5) 11B NMR (128 MHz C6D5Br) δ -240 (d 1JB-H = 82 Hz BH) 13C1H NMR (101 MHz


247 Hz CF) 1243 (ipso-C6F5) 636 (OMe) 583 (CHOMe) 551 (N-Cy) 497 (iPr) 267 (Cy)

246 (Cy) 183 (iPr) Anal calcd () for C28H23BF15NO C 4908 H 338 N 204 Found C

4945 H 329 N 230




1H iPr) 297 (m 1H N-Cy) 171 (m 3H Cy) 153 (m 1H Cy) 112 (m 1H CMeH) 112 (d

63

3JH-H = 60 Hz 3H iPr) 111 (d 3JH-H = 60 Hz 3H iPr) 104 (m 2H Cy) 086 (d 3JH-H = 66

Hz 3H Me) 078 (m 1H Cy) 068 (m 1H Cy) 19F NMR (377 MHz C6D5Br) δ -1337 (m 3JF-F = 21 Hz 2F o-C6F5) -1611 (t 3JF-F = 21 Hz 1F p-C6F5) -1652 (m 2F m-C6F5) 11B

NMR (128 MHz C6D5Br) δ -235 (d 1JB-H = 80 Hz BH) 13C1H NMR (101 MHz C6D5Br) δ


571 (N-Cy) 503 (iPr) 381 (Cy) 330 (Cy) 315 (CMeH) 293 (Cy) 241 (Cy) 219 (Me)

196 (iPr) 192 (iPr) Anal calcd () for C28H23BF15N C 5025 H 346 N 209 Found C

5011 H 350 N 216

[iPrNH2(35-Me2C6H9)][HB(C6F5)3] (210) N-Isoporpyl-35-dimethylaniline (121 mg 740

μmol) reaction time 72 h product (243 mg 360 μmol 48) Mixture of isomers was obtained

NMR data for one isomer is reported

1H NMR (400 MHz C6D5Br) δ 555 (br 2H NH2) 371 (br q 1JB-H = 82 Hz 1H BH) 300 -

280 (br m 2H iPr N-Cy) 182 (br m 1H Cy) 149 - 100 (m 5H Cy) 093 (m 6H iPr) 077

- 072 (m 1H Cy) 068 - 062 (m 6H Me) 059 - 048 (m 1H Cy) 19F NMR (377 MHz

C6D5Br) δ -1337 (m 2F o-C6F5) -1614 (t 3JF-F = 21 Hz 1F p-C6F5) -1652 (m 2F m-C6F5)

11B NMR (128 MHz C6D5Br) δ -235 (d 1JB-H = 82 Hz BH) 13C1H NMR (100 MHz

C6D5Br) partial δ 1479 (dm 1JC-F = 240 Hz CF) 1378 (dm 1JC-F = 249 Hz CF) 1365 (dm 1JC-F = 250 Hz CF) 1227 (ipso-C6F5) 560 (N-Cy) 494 (iPr) 410 (Cy) 378 (Cy) 270 (Cy)

212 (Me) 188 (iPr) Anal calcd () for C29H25BF15N C 5097 H 369 N 205 Found C

5087 H 399 N 212

[CyNH2CHPhCH2Ph][HB(C6F5)3] (211) cis-123-Triphenylaziridine (201 mg 740 μmol)


1H NMR (400 MHz CD2Cl2) δ 755 (m 1H p-Ph) 745 (m 4H Ph) 740 (m 3H Ph) 720

(m 2H Ph) 588 (br 2H NH2) 461 (t 3JH-H = 77 Hz 1H PhCH) 369 (br q 1JB-H = 85 Hz

1H BH) 344 (d 2H 3JH-H = 77 Hz PhCH2) 306 (m 1H N-Cy) 203 (m 1H Cy) 168 (m

4H Cy) 137 - 115 (br m 5H Cy) 19F NMR (377 MHz CD2Cl2) δ -1338 (m 3JF-F = 20 Hz

2F o-C6F5) -1627 (t 3JF-F = 20 Hz 1F p-C6F5) -1662 (m 2F m-C6F5) 11B NMR (128 MHz

CD2Cl2) δ -239 (d 1JB-H = 85 Hz BH) 13C1H NMR (101 MHz C6D5Br) δ 1481 (dm 1JC-F

= 245 Hz CF) 1382 (dm 1JC-F = 248 Hz CF) 1367 (dm 1JC-F = 248 Hz CF) 1333 (ipso-Ph)

1321 (ipso-Ph) 1310 (p-Ph) 1301 (Ph) 1298 (Ph) 1289 (Ph) 1287 (p-Ph) 1273 (Ph) 1235

64

(ipso-C6F5) 641 (PhCH) 582 (N-Cy) 403 (PhCH2) 306 (Cy) 289 (Cy) 241 (Cy) 238


395 N 187

[PhCH(Me)NH2Cy][HB(C6F5)3] (212) Method 1 N-(1-Phenylethylidene)aniline (144 mg

740 μmol) reaction time 96 h product (303 mg 420 μmol 57) Method 2 B(C6F5) (379 mg

0740 mmol) 3-methoxy-N-(1-phenylethyl)aniline (168 mg 0740 mmol) toluene (5 mL)

product (347 mg 0481 mmol 65)

1H NMR (400 MHz C6D5Br) δ 735 (m 3H o p-Ph) 721 (m 2H m-Ph) 618 (br 1H NH2)

566 (br 1H NH2) 428 (m 1H NH2CHMe) 383 (br q 1JB-H = 83 Hz 1H BH) 288 (m 1H

N-Cy) 190 (m 1H Cy) 166 (m 2H Cy) 157 (m 1H Cy) 154 (d 3JH-H = 69 Hz 3H Me)

146 (m 1H Cy) 126 (m 2H Cy) 098 (m 3H Cy) 19F NMR (377 MHz C6D5Br) δ -1336

(m 2F o-C6F5) -1613 (t 3JF-F = 20 Hz 1F p-C6F5) -1651 (m 2F m-C6F5) 11B NMR (128

MHz C6D5Br) δ -234 (d 1JB-H = 83 Hz BH) 13C1H NMR (101 MHz C6D5Br) δ 1481 (dm 1JC-F = 243 Hz CF) 1380 (dm 1JC-F = 241 Hz CF) 1365 (dm 1JC-F = 250 Hz CF) 1334

(ipso-Ph) 1296 (o-Ph) 1260 (m-Ph) 574 (NH2CHMe) 573 (N-Cy) 295 (Cy) 288 (Cy)

236 (Cy) 236 (Cy) 188 (Me) (p-Ph was not observed) Anal calcd () for C32H23BF15N C

5358 H 323 N 195 Found C 5374 H 300 N 189

[14-C6H10(iPrNH2)2][HB(C6F5)3]2 (213) N1N4-Di(propan-2-ylidene)benzene-14-diamine (70

mg 0037 mmol) reaction time 36 h product (293 mg 240 μmol 64)

1H NMR (400 MHz d8-THF) δ 784 (br 2H NH2) 376 (br q 1JB-H = 92 Hz 1H BH) 364 (m 3JH-H = 65 Hz 1H iPr) 335 (br m 1H N-Cy) 238 (m 2H Cy) 159 (m 2H Cy) 138 (d 3JH-

H = 65 Hz 6H iPr) 19F NMR (377 MHz d8-THF) δ -1346 (m 3JF-F = 20 Hz 2F o-C6F5) -

1670 (t 3JF-F = 20 Hz 1F p-C6F5) -1697 (m 2F m-C6F5) 11B NMR (128 MHz d8-THF) δ -

254 (d 1JB-H = 92 Hz BH) 13C1H NMR (101 MHz d8-THF) δ 1483 (dm 1JC-F = 237 Hz

CF) 1375 (dm 1JC-F = 242 Hz CF) 1362 (dm 1JC-F = 246 Hz CF) 1259 (ipso-C6F5) 528 (N-

Cy) 486 (iPr) 274 (Cy) 184 (iPr) Anal calcd () for C48H30B2F30N2 C 4701 H 247 N

228 Found C 4686 H 247 N 232

[(14-C6H10(iPrNH2))2CH2][HB(C6F5)3]2 (214) 44-Methylenebis(N-isopropylaniline) (104

mg 370 μmol) reaction time 76 h product (372 mg 280 μmol 76)

65


1H iPr) 276 (m 1H N-Cy) 168 (m 1H Cy) 151 (m 2H Cy) 145 (m 1H CH2) 132 (m

2H Cy) 091 (m 2H Cy) 089 (m 2H Cy) 089 (d 3JH-H = 68 Hz 6H iPr) 19F NMR (377

MHz C6D5Br) δ -1331 (m 3JF-F = 20 Hz 2F o-C6F5) -1619 (t 3JF-F = 20 Hz 1F p-C6F5) -

1653 (m 2F m-C6F5) 11B NMR (128 MHz C6D5Br) δ -240 (d 1JB-H = 81 Hz BH) 13C1H

NMR (101 MHz C6D5Br) δ 1486 (dm 1JC-F = 243 Hz CF) 1381 (dm 1JC-F = 247 Hz CF)

1385 (dm 1JC-F = 247 Hz CF) 569 (iPr) 500 (N-Cy) 432 (CH2) 296 (Cy) 272 (CH2-Cy)

242 (Cy) 190 (iPr) Anal calcd () for C55H42B2F30N2 C 4995 H 320 N 212 Found C

4973 H 333 N 221

[iPr2NHPh][HB(C6F5)3] (215) In a glove box B(C6F5)3 (379 mg 740 μmol) and NN-

diisopropylaniline (131 mg 740 μmol) were dissolved in C6D5Br (05 mL) and added into a

Teflon capped sealed J-Young tube The J-Young tube was degassed three times through a

freeze-pump-thaw cycle on the vacuumH2 line and filled with H2 (4 atm) at -196 ordmC and placed

in a 110 ordmC oil bath for 16 h To the C6D5Br solution pentane was added drop wise until the

product precipitated The white solid was isolated (442 mg 640 μmol 87) Crystals suitable

for X-ray diffraction were grown from a layered C6D5Brpentane solution at -30 ordmC

1H NMR (400 MHz C6D5Br) δ 716 (m 3H o p-Ph) 693 (m 2H m-Ph) 670 (br 1H NH)

371 (br q 1JB-H = 85 Hz 1H BH) 358 (m 3JH-H = 63 Hz 2H iPr) 093 (d 3JH-H = 63 Hz 6H

iPr) 077 (d 3JH-H = 63 Hz 6H iPr) 19F NMR (377 Hz C6D5Br) δ -1326 (m 3JF-F = 20 Hz


C6D5Br) δ -245 ppm (br d 1JB-H = 85 Hz BH) 13C1H NMR (101 MHz C6D5Br) δ 1484

(dm 1JC-F = 243 Hz CF) 1381 (dm 1JC-F = 247 Hz CF) 1365 (dm 1JC-F = 247 Hz CF) 1322

(ipso-Ph) 1304 (m-Ph) 1231 (p-Ph) 1211 (o-Ph) 584 (iPr) 188 (iPr) 168 (iPr) Anal calcd

() for C30H21BF15N C 5212 H 306 N 203 Found C 5183 H 329 N 211

Synthesis of 216 - 218 is similar to the general procedure used for compounds 23 - 214 Since

compounds [(2-FC6H10)NH2iPr][HB(C6F5)3] 216b and [(3-FC6H10)NH2iPr][HB(C6F5)3] 217b

were present in trace amounts (5) isolation and characterization proved difficult therefore

spectroscopic data for the two compounds has not been reported

[iPrNH2Cy][FB(C6F5)3] (216a) B(C6F5)3 (379 mg 0740 mmol) 2-fluoro-N-isopropylaniline

(115 mg 0740 mmol) or 3-fluoro-N-isopropylaniline (115 mg 0740 mmol) toluene (5mL)

66

reaction time 72 h product from 2-fluoro-N-isopropylaniline (294 mg 0440 mmol 59)

product from 3-fluoro-N-isopropylaniline (381 mg 0570 mmol 77) Crystals suitable for x-

ray diffraction were grown from a layered C6D5Brpentane solution at -30 ordmC

1H NMR (400 MHz C6D5Br) δ 561 (br 2H NH2) 288 (m 3JH-H = 64 Hz 1H iPr) 262 (br

m 1H N-Cy) 149 (m 2H Cy) 144 (m 2H Cy) 135 (m 1H Cy) 092 - 083 (m 5H Cy)

085 (d 1JH-H = 63 Hz 6H iPr) 19F NMR (377 MHz CD2Cl2) δ -1370 (m 6F o-C6F5) -1616

(t 3JF-F = 22 Hz 3F p-C6F5) -1669 (m 6F m-C6F5) -1795 (br s 1F BF) 11B NMR (128

MHz CD2Cl2) δ 051 (br s BF) 13C1H NMR (101 MHz C6D5Br) δ 1483 (dm 1JC-F = 239

Hz CF) 1394 (dm 1JC-F = 241 Hz CF) 1373 (dm 1JC-F = 249 Hz CF) 560 (N-Cy) 489

(iPr) 293 (Cy) 245 (Cy) 241 (Cy) 188 (iPr) Anal calcd () for C27H20BF16N C 4817 H

299 N 208 Found C 4804 H 307 N 210

[(4-FC6H8)NH2iPr][HB(C6F5)3] (218) B(C6F5)3 (379 mg 074 mmol) 4-fluoro-N-

isopropylaniline (113 mg 074 mmol) toluene (5 mL) reaction time 72 h product (308 mg

0460 mmol 62) Crystals suitable for X-ray diffraction were obtained from a layered solution

of dichloromethanepentane at -30 degC

1H NMR (400 MHz C6D5Br) δ 582 (br s 2H NH2) 477 (dm 3JF-H = 14 Hz 1H CH=CF)

355 (br q 1JB-H = 81 Hz 1H BH) 345 (m 1H iPr) 293 (m 1H N-Cy) 192 - 133 (m 6H

CH2 groups of Cy) 081 (d 3JH-H = 66 Hz 6H iPr) 19F NMR (377 MHz C6D5Br) δ -9903

(dm 3JF-H = 14 Hz 1F FC=CH) -1331 (m 3JF-F = 23 Hz 6F o-C6F5) -1606 (t 3JF-F = 21 Hz


BH) 13C1H NMR (101 MHz C6D5Br) δ 1584 (d 1JC-F = 255 Hz CF=CH) 1484 (dm 1JC-F =

224 Hz C6F5)1385 (dm 1JC-F = 247 Hz C6F5)1369 (dm 1JC-F = 247 Hz C6F5) 1230 (ipso-

C6F5) 974 (d 2JC-F = 20 Hz CF=CH) 518 (iPr) 504 (N-Cy) 254 (d 2JC-F = 81 Hz CH2CF)

247 (d 3JC-F = 90 Hz CH2CH=CF) 228 (CH2) Anal calcd () for C27H18BF16N C 4831 H

270 N 209 Found C 4793 H 282 N 203

Synthesis of 219 and 220 is similar to the general procedure used for compounds 23 - 214

Synthesis of [C6H10NHCH(CH3)Ph][HB(C6F5)3] (219) Method 1 B(C6F5) (358 mg 0700

mmol) 4-methoxy-N-(1-phenylethylidene)aniline (113 mg 0500 mmol) toluene (4 mL) (107

67

mg 0150 mmol 30) Crystals suitable for X-ray diffraction were obtained from a layered

solution of dichloromethanepentane at -30 degC

Method 2 In the glovebox trans-(4-CH3OC6H10)NHCH(CH3)Ph (81 mg 340 μmol) and

B(C6F5)3 (17 mg 340 μmol) were dissolved in d8-toluene (04 mL) and added into a Teflon

capped J-Young tube The tube was degassed once through a freeze-pump-thaw cycle on the

vacuumH2 line and filled with H2 (4 atm) at -196 ordmC The reaction was complete after 12 h at

110 degC The solvent was removed under vacuum and the residue was washed with pentane (2

mL) The product was dried under vacuum and collected (82 mg 110 μmol 33)

1H NMR (500 MHz CD2Cl2) δ 752 (tm 3JH-H = 77 Hz 1H p-Ph)

746 (tm 3JH-H = 77 Hz 2H m-Ph) 735 (dm 3JH-H = 77 Hz 2H o-

Ph) 555 (br m 1H NH) 447 (dd 3JH-H = 95 Hz 48 Hz 1H H1)

415 (dq 3JH-H = 102 Hz 68 Hz 1H CH(CH3)Ph) 374 (m JH-H = 95

Hz 48 Hz 1H H5) 363 (br q 1JB-H = 83 Hz 1H BH) 229 (m 1H

H3) 223 (m 1H H4) 215 (m 1H H2) 201 (m 1H H3) 196 (m 1H H6) 190 (m 1H H2)

188 (m 1H H4) 177 (d 3JH-H = 68 Hz 3H CH3) 176 (m 1H H6) 19F NMR (377 MHz

CD2Cl2) δ -1304 (m 2F o-C6F5) -1638 (t 1F 3JF-F = 21 Hz p-C6F5) -1670 (m 2F m-C6F5)

11B NMR (128 MHz CD2Cl2) δ -249 (d 1JB-H = 83 Hz BH) 13C1H NMR (125 MHz

CD2Cl2) δ 1482 (dm 1JC-F = 236 Hz C6F5) 1378 (dm 1JC-F = 245 Hz C6F5) 1364 (dm 1JC-F

= 249 Hz C6F5) 1346 (ipso-Ph) 1308 (p-Ph) 1301 (m-Ph) 1266 (o-Ph) 1246 (ipso-C6F5)

652 (C5) 647 (C1) 586 (CH(CH3)Ph) 277 (C2) 273 (C6) 254 (C3 C4) 188 (CH3) Anal

calcd () for C32H21BF15N C 5373 H 296 N 196 Found 5384 H 321 N 200

[(o-CH3OC6H10)NH2CH(CH3)Ph][HB(C6F5)3] (220) Ratio of cis and trans isomers = 11

determined by 1H NMR spectroscopy The trans isomer has been isolated and characterized

B(C6F5) (379 mg 0740 mmol) 2-methoxy-N-(1-phenylethyl)aniline (168 mg 0740 mmol)

toluene (5 mL) product (508 mg 0680 mmol 92) Crystals suitable for X-ray diffraction were

obtained from a layered solution of dichloromethanepentane at -30 degC

1H NMR (400 MHz C6D5Br) δ 716 (m 3H m p-Ph) 691 (m 2H o-

Ph) 655 (br s 2H NH2) 413 (q 3JH-H = 64 Hz 1H CH(Me)Ph) 365

(br q 1JB-H = 92 Hz 1H BH) 313 (ddd 3JH-H = 107 Hz 43 Hz 1H

CHOCH3) 298 (s 3H OCH3) 237 (td 3JH-H = 107 Hz 1H CH2CHNH2) 180 (m 1H DCH2)

68

173 (dm 3JH-H = 136 Hz 1H ACH2) 140 (m 2H DCCH2) 128 (d 3JH-H = 64 Hz 3H

CH(CH3)Ph) 120 (m 1H BCH2) 095 (pseudo qt JH-H = 136 Hz 3JH-H = 31 Hz 1H BCH2)

066 (pseudo qt JH-H = 136 Hz 3JH-H = 31 Hz 1H CCH2) 039 (pseudo qd JH-H = 136 Hz 3JH-

H = 31 Hz 1H ACH2) 19F NMR (377 MHz C6D5Br) δ -1341 (m 2F o-C6F5) -1634 (t 3JF-F =

21 Hz 1F p-C6F5) -1667 (m 2F m-C6F5) 11B NMR (128 MHz C6D5Br) δ -246 (d 1JB-H = 92

Hz BH) 13C1H NMR (101 MHz C6D5Br) δ 1484 (dm 1JC-F = 235 Hz C6F5) 1381 (dm 1JC-F = 246 Hz C6F5) 1367 (dm 1JC-F = 247 Hz C6F5) 1334 (ipso-Ph) 1304 (p-Ph) 1299 (m-

Ph) 1264 (o-Ph) 1239 (ipso-C6F5) 778 (CHOCH3) 611 (CH2CHNH2) 571 (CH(CH3)Ph)

554 (OCH3) 279 (ACH2) 257 (DCH2) 236 (CCH2) 224 (BCH2) 202 (CH3) Anal calcd ()

for C33H25BF15NO C 5303 H 337 N 187 Found 5288 H 357 N 190

Synthesis of trans-[(4-CH3OC6H10)NH2CH(CH3)Ph][B(C6F5)4] (221a) Part 1 In a Schlenk

tube trans-(4-CH3OC6H10)NHCH(CH3)Ph (16 mg 680 μmol) was dissolved in pentane (2 mL)

and hydrogen chloride (68 μL 027 mmol 40 M in 14-dioxane) was added drop wise White

precipitate was immediately formed The solvent was decanted and the solid was washed with

pentane (2 mL) and dried in vacuo to yield trans-4-(CH3OC6H10)NHCH(CH3)Ph HCl (163 mg

610 μmol 89)

Part 2 In the glovebox a 4 dram vial was charged with trans-4-(CH3OC6H10)NHCH(CH3)Ph

HCl (61 mg 0026 mmol) in dichloromethane (8 mL) and K B(C6F5)4 (162 mg 260 mmol)

was added at once The reaction was allowed to stir for 16 h at room temperature The mixture

was filtered through Celite and the solvent was removed under vacuum The product was

obtained as a white solid (209 mg 230 μmol 88)

1H NMR (400 MHz C6D5Br) δ 719 (m 2H m-Ph) 690 (m 3H o p-Ph) 510 (br s 2H NH2)

402 (q 3JH-H = 69 Hz 1H CH(CH3)Ph) 310 (s 3H OCH3) 272 (m 2H CyCHOCH3 CyCHN) 174 (m 3H CyCH2) 156 (m 1H CyCH2) 127 (d 3JH-H = 69 Hz 3H CH(CH3)Ph

093 - 084 (m 4H CyCH2) 19F NMR (377 MHz C6D5Br) δ -1318 (m 2F o-C6F5) -1610 (t 3JF-F = 21 Hz 1F p-C6F5) -1653 (m 2F m-C6F5) 11B NMR (128 MHz C6D5Br) δ -164 (s

B(C6F5)4)

Synthesis of trans-[(4-CH3OC6H10)NH2CH(CH3)Ph][HB(C6F5)3] (221b) In the glovebox a 4

dram vial was charged with trans-4-(CH3OC6H10)NHCH(CH3)Ph HCl (93 mg 0034 mmol) in

dichloromethane (8 mL) and Na HB(C6F5)3 (185 mg 340 μmol) was added at once The

69

reaction was allowed to stir for 16 h at room temperature The mixture was filtered through

Celite and the solvent was removed under vacuum The product was obtained as a white solid

(193 mg 260 μmol 76) Preparation of Na HB(C6F5)3 is reported in Chapter 3

1H NMR (400 MHz C6D5Br) δ 716 (m 3H Ph) 702 (m 2H Ph) 546 (br 2H NH2) 407 (q 3JH-H = 68 Hz 1H CH(CH3)Ph) 347 (br q 1JB-H = 78 Hz 1H BH) 307 (s 3H OCH3) 283

(tt 3JH-H = 106 Hz 46 Hz 1H CyCHOCH3) 268 (tt 3JH-H = 117 Hz 39 Hz 1H CyCHN) 183

(m 3H CyCH2) 156 (dm 3JH-H = 128 Hz 1H CyCH2) 132 (d 3JH-H = 68 Hz CH(CH3)Ph)

121 (m 2H CyCH2) 084 (m 2H CyCH2) 19F NMR (377 MHz C6D5Br) δ -1334 (m 2F o-

C6F5) -1604 (t 3JF-F = 22 Hz 1F p-C6F5) -1643 (m 2F m-C6F5) 11B NMR (128 MHz

C6D5Br) δ -238 (d 1JB-H = 78 Hz BH)

Synthesis of [C6H10NH(iPr)][CH3OB(C6F5)3] (222) In the glovebox a Schlenk tube (25 mL)

was charged with trans-(4-CH3OC6H10)NH(iPr) (253 mg 0148 mmol) in toluene (05 mL) and

B(C6F5) (758 mg 0148 mmol) dissolved in toluene (05 mL) was added at once The Schlenk

was sealed and heated at 110 degC for 2 h and the solvent was removed under vacuum The crude

solid was washed with pentane (2 mL) to yield the product as a white solid (991 mg 0145

mmol 98) Crystals suitable for X-ray diffraction were obtained from a layered solution of

dichloromethanepentane at -30 degC

1H NMR (500 MHz CD2Cl2) δ 810 (s 1H NH) 413 (m 2H CH2CH) 315 (m 3JH-H = 66

Hz 1H iPr) 302 (s 3H BOCH3) 222 (dm 1JH-H = 93 Hz 2H ACH2) 205 (dm 1JH-H = 100

Hz 2H BCH2) 181 (dm 1JH-H = 100 Hz 2H BCH2) 172 (dm 1JH-H = 93 Hz 2H ACH2) 136

(d 3JH-H = 66 Hz 6H iPr) 19F NMR (377 MHz CD2Cl2) δ -1351 (br 2F o-C6F5) -1620 (t 3JF-F = 20 Hz 1F p-C6F5) -1664 (m 2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ -242 (s

BOCH3) 13C1H NMR (125 MHz CD2Cl2) δ 1482 (dm 1JC-F = 241 Hz C6F5) 1388 (dm 1JC-F = 262 Hz C6F5) 1370 (dm 1JC-F = 252 Hz C6F5) 1231 (ipso-C6F5) 634 (CH2CH) 522

(BOCH3) 502 (iPr) 274 (ACH2) 258 (BCH2) 185 (iPr) Anal calcd () for C28H21BF15N05

CH2Cl2 C 4717 H 306 N 193 Found 4674 H 327 N 199 HRMS-DART mz [M] calcd

for C9H18N+ 1401 Found 1401

Synthesis of [C6H10NH(iPr)][HB(C6F5)3] (223) Method 1 In the glovebox trans-(4-

CH3OC6H10)NH(iPr) (250 mg 0150 mmol) and B(C6F5)3 (760 mg 0150 mmol) were

dissolved in d8-toluene (04 mL) and added into a Teflon capped J-Young tube The tube was

70

degassed once through a freeze-pump-thaw cycle on the vacuumH2 line and filled with H2 (4

atm) at -196 ordmC The reaction was complete after 12 h at 110 degC The solvent was removed under

vacuum and the residue was washed with pentane (2 mL) The product was collected as a white

powder (607 mg 930 μmol 62)

Method 2 In the glovebox compound [C6H10NH(iPr)][CH3OB(C6F5)3] (222) (200 mg 290

μmol) was dissolved in d8-toluene (04 mL) and added into a Teflon capped J-Young tube The

tube was degassed once through a freeze-pump-thaw cycle on the vacuumH2 line and filled with

H2 (4 atm) at -196 ordmC The reaction was complete after 12 h at 110 degC

1H NMR (400 MHz C6D5Br) δ 510 (br m 1H NH) 367 (br q 1JB-H = 76 Hz 1H BH) 347

(br s 2H CH) 242 (m 1H iPr) 162 (m 2H CH2) 131 (m 2H CH2) 111 (m 2H CH2) 093

(m 2H CH2) 138 (d 3JH-H = 66 Hz 6H iPr) 19F NMR (377 MHz C6D5Br) δ -1338 (m 3JF-F

= 21 Hz 2F o-C6F5) -1622 (t 3JF-F = 21 Hz 1F p-C6F5) -1658 (m 2F m-C6F5) 11B NMR

(128 MHz C6D5Br) δ -239 (d 1JB-H = 76 Hz BH) 13C1H NMR (101 MHz C6D5Br) δ 1483


(ipso-C6F5) 636 (CHCH2) 500 (iPr) 271 (CH2) 248 (CH2) 186 (iPr) Anal calcd () for


Compounds 224 - 235 were prepared in a similar fashion thus only one preparation is detailed

In the glove box a 50 mL Teflon screw cap Schlenk tube equipped with a stir bar was charged

with a solution of B(C6F5)3 (0379 g 0740 mmol) and the respective N-heterocycle in toluene (5

mL) The reaction tube was degassed three times through a freeze-pump-thaw cycle on the

vacuumH2 line and filled with H2 (4 atm) at -196 ordmC After the addition of H2 the reaction tube

was placed in a 115 ordmC oil bath for the indicated reaction time The solvent was then removed

under vacuum and the crude product was washed with pentane to yield the product as a white

solid

[26-Ph2C5H8NH2][HB(C6F5)3] (224) 26-Diphenylpyridine (171 mg 0740 mmol) reaction

time 16 h product (511 g 0680 mmol 92) Crystals suitable for X-ray diffraction were grown

from a layered solution of dichloromethanepentane at -30 ordmC Isomer ratio by 1HNMR

spectroscopy meso 91 rac 9

71

meso-[26-Ph2C5H8NH2][HB(C6F5)3] 1H NMR (400 MHz CD2Cl2) δ 734 (tt 3JH-H = 70 Hz

4JH-H = 24 Hz 2H p-Ph) 726 (m 8H o m-Ph) 590 (br 2H NH2) 453 (m 3JH-H = 122 Hz 3JH-H = 24 Hz 2H C(H)Ph) 339 (br q 1JB-H = 90 Hz 1H BH) 226 (br m 3H CH2) 212 (m

2H CH2) 189 (m 1H CH2) 19F NMR (377 MHz CD2Cl2) δ -1340 (m 2F o-C6F5) -1634 (t 3JF-F = 20 Hz 1F p-C6F5) -1666 (m 2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ -246 (d 1JB-H = 90 Hz BH) 13C1H NMR (101 MHz CD2Cl2) δ 1483 (dm 1JC-F = 237 Hz CF) 1380

(dm 1JC-F = 244 Hz CF) 1367 (dm 1JC-F = 246 Hz CF) 1338 (ipso-Ph) 1313 (p-Ph) 1271

(Ph) 1264 (Ph) 1241 (ipso-C6F5) 657 (C(H)(Ph)) 297 (CH2) 233 (CH2) Anal calcd ()

for C35H21BF15N C 5595 H 282 N 186 Found C 5547 H 303 N 186

[26-Me2C5H8NH2][HB(C6F5)3] (225) 26-Dimethylpyridine (793 mg 0740 mmol) reaction

time 60 h product (390 mg 0621 mmol 84) Crystals suitable for X-ray diffraction were

grown from a layered solution of bromobenzenepentane at -30 ordmC over 48 h Isomer ratio by 1HNMR spectroscopy meso 80 rac 20

meso-[26-Me2C5H8NH2][HB(C6F5)3] 1H NMR (400 MHz C6D5Br) δ 508 (br 2H NH2) 345

(br q 1JB-H = 83 Hz 1H BH) 268 (m 2H NC(H)Me) 137 (m 4H CH2) 086 (d 3JH-H = 64

Hz 6H CH3) 077 (m 2H CH2) 19F NMR (377 MHz C6D5Br) δ -1341 (m 2F o-C6F5) -

1617 (t 3JF-F = 20 Hz 1F p-C6F5) -1655 (m 2F m-C6F5) 11B NMR (128 MHz C6D5Br) δ -



(NCH) 303 (CH2) 220 (CH2) 193 (CH3) Anal calcd () for C25H17BF15N C 4787 H 273

N 223 Found C 4764 H 290 N 222

(2-(EtOCO)C5H9NH)B(C6F5)3 (226) Ethyl 2-picolinate (112 mg 0740 mmol) reaction time

36 h product (366 mg 0547 mmol 74) The isolated product consisted of an equal ratio of

both diastereomers Anal calcd () for C26H15BF15NO2 C 4667 H 226 N 209 Found C

4660 H 247 N 211

RSSR-[2-(OCOEt)C5H9NHB(C6F5)3] 1H NMR (400 MHz CD2Cl2)

δ 590 (m 1H NH) 430 (m 1H CH(H)NH) 418 (br m 1H

CHOCOEt) 393 (dq 2JH-H = 108 Hz 3JH-H = 71 Hz 1H Et) 373

(dq 2JH-H = 108 Hz 3JH-H = 71 Hz 1H Et) 320 (dm 2JH-H = 126 Hz 1H CH(H)NH) 217

(m 2H CH2) 204 (dm 2JH-H = 134 Hz 1H CH2) 184 (m 1H CH2) 175 (m 1H CH2) 119

72

(t 3JH-H = 72 Hz 3H Et) 103 (m 1H CH2) 19F NMR (377 MHz CD2Cl2) δ -1264 (m 1F o-

C6F5) -1280 (m 1F o-C6F5) -1295 (m 1F o-C6F5) -1297 (m 1F o-C6F5) -1404 (m 1F o-

C6F5) -1433 (m 1F o-C6F5) -1555 (t 3JF-F = 21 Hz 1F p-C6F5) -1573 (t 3JF-F = 21 Hz 1F

p-C6F5) -1575 (t 3JF-F = - 21 Hz 1F p-C6F5) -1616 (m 1F m-C6F5) -1621 (m 1F m-C6F5) -

1628 (m 1F m-C6F5) -1631 (m 1F m-C6F5) -1640 (m 1F m-C6F5) -1649 (m 1F m-C6F5)

11B NMR (128 MHz CD2Cl2) δ -486 (s BNH) 13C1H NMR (101 MHz CD2Cl2) δ 1674

(OCO) 636 (Et) 568 (CHOCOEt) 445 (CH(H)NH) 305 (CH2) 208 (CH2) 181 (CH2) 134

(Et)

RRSS-[2-(OCOEt)C5H9NHB(C6F5)3] 1H NMR (400 MHz CD2Cl2) δ

743 (br m 1H NH) 440 (dq 2JH-H = 107 Hz 3JH-H = 71 Hz 1H Et)

438 (dq 2JH-H = 91 Hz 3JH-H = 71 Hz 1H Et) 424 (br m 1H

CHOCOEt) 350 (ddd 2JH-H = 134 Hz 3JH-H = 89 Hz 3JH-H = 49 Hz 1H CH(H)NH) 333

(dm JH-H = 133 Hz 1H CH(H)NH) 218 (m 1H CH2) 208 (m 1H CH2) 185 (m 1H CH2)

154 (m 1H CH2) 151 (m 1H CH2) 135 (t 3JH-H = 71 Hz 3H Et) 124 (m 1H CH2) 19F

NMR (377 MHz CD2Cl2) δ -1276 (m 1F o-C6F5) -1285 (m 2F o-C6F5) -1291 (m 1F o-

C6F5) -1371 (m 1F o-C6F5) -1421 (m 1F o-C6F5) -1549 (t 3JF-F = 21 Hz 1F p-C6F5) -

1572 (t 3JF-F = 21 Hz 1F p-C6F5) -1578 (t 3JF-F = 21 Hz 1F p-C6F5) -1618 (m 1F m-C6F5)

-1626 (m 1F m-C6F5) -1630 (m 3F m-C6F5) -1633 (m 1F m-C6F5) 11B NMR (128 MHz

CD2Cl2) δ -486 (s BN) 13C1H NMR (101 MHz CD2Cl2) δ 1712 (OCO) 616 (Et) 581

(CHOCOEt) 457 (CH(H)NH) 259 (CH2) 235 (CH2) 171 (CH2) 139 (Et)

(2-PhC5H9NH)B(C6F5)3 (227a) and [2-PhC5H9NH2][HB(C6F5)3] (227b) 2-Phenylpyridine

(115 mg 0740 mmol) reaction time 48 h product (269 mg 0400 mmol 54) Crystals

suitable for X-ray diffraction were grown from a layered solution of dichloromethanepentane at

-30 ordmC The isolated product consisted of 227a (RSSR 70) 227a (SSRR 10) 227b (20)

Anal calcd () for C29H15BF15N C 5158 H 254 N 209 Found C 5209 H 258 N 210

RSSR-[2-(Ph)C5H9NHB(C6F5)3] 1H NMR (400 MHz CD2Cl2) δ 727

(m 2H Ph) 714 (m 3H Ph) 555 (br s 1H NH) 415 (ddd 3JH-H = 111

Hz 3JH-H = 94 Hz 36 Hz 1H CHPh) 356 (dm 2JH-H = 132 Hz 1H CH(H)NH) 257 (ddd 2JH-H = 132 Hz 3JH-H = 103 Hz 3JH-H = 31 Hz 1H CH(H)NH) 199 - 135 (m 6H CH2) 19F

NMR (377 MHz C6D5Br) δ -1216 (m 1F o-C6F5) -1236 (m 1F o-C6F5) -1274 (m 1F o-

73

C6F5) -1286 (m 1F o-C6F5) -1312 (m 1F o-C6F5) -1426 (m 1F o-C6F5) -1534 (t 3JF-F =

22 Hz 1F p-C6F5) -1566 (t 3JF-F = 21 Hz 1F p-C6F5) -1567 (t 3JF-F = 21 Hz 1F p-C6F5) -

1615 (m 2F m-C6F5) -1620 (m 3F m-C6F5) -1624 (m 1F m-C6F5) 11B NMR (128 MHz

CD2Cl2) δ -391 (s BN) 13C1H NMR (101 MHz CD2Cl2) δ 1385 (ipso-Ph) 1297 (p-Ph)

1291 (Ph) 1285 (Ph) 646 (CHPh) 521 (NCH2) 355 (CH2) 248 (CH2) 219 (CH2)

SSRR-[2-(Ph)C5H9NHB(C6F5)3] 1H NMR (400 MHz C6D5Br) δ 710 -

681 (m 5H Ph) 581 (br s 1H NH) 449 (m 1H CHPh) 347 (dm 2JH-H = 125 Hz 1H CH(H)NH) 321 (m 2JH-H = 125 Hz 1H CH(H)NH) 185 (m 2H CH2)

176 (m 2H CH2) 128 (m 2H CH2) 19F NMR (377 MHz C6D5Br) δ -1249 (m 1F o-C6F5)

-1263 (m 1F o-C6F5) -1268 (m 1F o-C6F5) -1287 (m 1F o-C6F5) -1390 (m 1F o-C6F5) -

1431 (m 1F o-C6F5) -1555 (t 3JF-F = 21 Hz 1F p-C6F5) -1559 (t 3JF-F = 21 Hz 1F p-C6F5)

-1562 (t 3JF-F = 21 Hz 1F p-C6F5) -1598 (m 1F m-C6F5) -1610 (m 1F m-C6F5) -1617 (m

1F m-C6F5) -1620 (m 1F m-C6F5) -1622 (m 1F m-C6F5) -1643 (m 1F m-C6F5) 11B NMR

(128 MHz CD2Cl2) δ -39 (s BN) 13C1H NMR (101 MHz CD2Cl2) δ 1365 (ipso-Ph)1294

(p-Ph) 1283 (Ph) 1256 (Ph) 629 (CHPh) 454 (NCH2) 350 (CH2) 297 (CH2) 260 (CH2)

[2-PhC5H9NH2][HB(C6F5)3] (227b) 1H NMR (400 MHz CD2Cl2) δ 710 - 681 (m 5H Ph)

557 (br s 2H NH2) 355 (dd 3JH-H = 117 Hz 28 Hz 1H CHPh) 330 (br q 1JB-H = 86 Hz

1H BH) 295 (dm JH-H = 124 Hz 1H CH(H)NH2) 244 (pseudo td JH-H = 124 Hz 3JH-H = 30

Hz 1H CH(H)NH2) 186 (m 2H CH2) 165 (m 1H CH2) 157 (m 1H CH2) 141 (m 1H

CH2) 137 (m 1H CH2) 19F NMR (377 MHz CD2Cl2) δ -1344 (m 2F o-C6F5) -1610 (t 3JF-

F = 20 Hz 1F p-C6F5) -1667 (m 2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ -248 (d 1JB-H

= 86 Hz BH) 13C1H NMR (101 MHz CD2Cl2) δ 1399 (ipso-Ph) 1297 (Ph) 1295 (p-Ph)

1267 (Ph) 625 (CHPh) 471 (NCH2) 327 (CH2) 242 (CH2) 240 (CH2)

[2-MeC9H15NH2][HB(C6F5)3] (228) 2-Methylquinoline (106 mg 0740 mmol) reaction time

48 h product (331 mg 500 mmol 67) Crystals suitable for X-ray diffraction were grown from

a layered solution of dichloromethanepentane at -30 ordmC About 60 of the isolated reaction

product consisted of the SSSRRR diastereomer

1H NMR (400 MHz C6D5Br) δ 602 (br 1H NH2) 460 (br 1H NH2) 336 (br q 1JB-H = 83

Hz 1H BH) 315 (dt 3JH-H = 100 Hz 52 Hz 1H NCHCH) 276 (m 1H CHMe) 145 - 096

(m 8H CH2) 110 (m 1H CHCHN) 093 - 067 (m 4H CH2) 081 (d 3JH-H = 64 Hz 3H

74

Me) 19F NMR (377 MHz C6D5Br) δ -1335 (m 2F o-C6F5) -1607 (t 3JF-F = 22 Hz 1F p-

C6F5) -1646 (m 2F m-C6F5) 11B NMR (128 MHz C6D5Br) δ -241 (d 1JB-H = 83 Hz BH)


Hz CF) 1369 (dm 1JC-F = 249 Hz CF) 1233 (ipso-C6F5) 577 (NCH) 493 (CHMe) 322

(CHCHN) 281 (CH2) 272 (CH2) 255 (CH2) 240 (CH2) 236 (CH2) 211 (CH2) 189 (Me)


[2-PhC9H15NH2][HB(C6F5)3] (229) B(C6F5)3 (289 mg 0564 mmol) 2-phenylquinoline (116

mg 0564 mmol) reaction time 48 h product (391 mg 536 mmol 95) Crystals suitable for

X-ray diffraction were grown from a layered solution of dichloromethanepentane at -30 ordmC

About 73 of the reaction mixture consisted of the reported SSSRRR diastereomer

1H NMR (400 MHz CD2Cl2) δ 733 (tm 3JH-H = 73 Hz 1H p-Ph) 726 (tm 3JH-H = 73 Hz

2H m-Ph) 720 (dm 3JH-H = 73 Hz 2H o-Ph) 646 (br 1H NH2) 501 (br t 1H NH2) 433

(dm 3JH-H = 105 Hz 33 Hz 1H C(H)Ph) 380 (br m 1H CH2C(H)NH2) 320 (br q 1JB-H = 87

Hz 1H BH) 218 - 108 (m 13H CH2C(H)CH2 and CH2) 19F NMR (377 MHz C6D5Br) δ -

1334 (m 2F o-C6F5) -1612 (t 3JF-F = 21 Hz 1F p-C6F5) -1647 (m 2F m-C6F5) 11B NMR

(128 MHz C6D5Br) δ -242 (d 1JB-H = 87 Hz BH) 13C1H NMR (101 MHz CD2Cl2) δ 1342

(ipso-Ph) 1312 (p-Ph) 1301 (m-Ph) 1269 (o-Ph) 647 (CH2C(H)NH2) 601 (C(H)Ph) 345

(CH2C(H)CH2) 291 (CH2) 285 (CH2) 251 (CH2) 249 (CH2) 248 (CH2) 197 (CH2) Anal

calcd () for C33H23BF15N C 5434 H 318 N 192 Found C 5431 H 331 N 192


48 h product (375 mg 0562 mmol 76) Crystals suitable for X-ray diffraction were grown

from a layered solution of dichloromethanepentane at -30 ordmC The reported SSSRRR

diastereomer was only observed


Hz 1H BH) 327 (dm 2JH-H = 121 Hz 1H NH2CH(H)) 263 (dm 3JH-H = 112 Hz coupling to

NH2 is observed in 1H1H-cosy 1H CHN) 252 (qt 2JH-H = 121 Hz 3JH-H = 27 Hz 1H

NH2CH(H)) 141 - 133 (br m 2H CH2) 134 (m 1H CH2CHCH2) 125 - 114 (br m 4H

CH2) 122 (m 1H CHMe) 102 (m 1H CH2) 089 (m 2H CH2) 063 (d 3JH-H = 75 Hz 3H

Me) 058 (m 1H CH2) 19F NMR (377 MHz C6D5Br) δ -1343 (m 2F o-C6F5) -1618 (t 3JF-F

= 21 Hz 1F p-C6F5) -1656 (m 2F m-C6F5) 11B NMR (128 MHz C6D5Br) δ -242 (d 1JB-H =

75

80 Hz BH) 13C1H NMR (101 MHz C6D5Br) δ 1484 (dm 1JC-F = 234 Hz CF) 1383 (dm 1JC-F = 246 Hz CF) 1368 (dm 1JC-F = 249 Hz CF) 1237 (ipso-C6F5) 632 (CHN) 478

(NH2CH(H)) 339 (CH2CHCH2) 337 (CHMe) 271 (CH2) 268 (CH2) 243 (CH2) 231 (CH2)

178 (CH2) 163 (Me) Anal calcd () for C28H21BF15N C 5040 H 317 N 210 Found C

5026 H 330 N 209

[C13H22NH2][HB(C6F5)3] (231a) Acridine (132 mg 0740 mmol) reaction time 36 h product

(398 mg 0562 mmol 76) Crystals suitable for X-ray diffraction were grown from a layered

solution of bromobenzenepentane at 25 ordmC The isolated product is a mixture of the SRSRRSRS

and RRSSSSRR isomers in a 11 ratio The SRSRRSRS was separated by crystallization

1H NMR (400 MHz CD2Cl2) δ 626 (br m 1H NH2) 513 (br m 1H NH2) 327 (br q 1JB-H =

86 Hz 1H BH) 285 (dm 3JH-H = 111 Hz 40 Hz 2H CHN) 182 (m 2H NH2CHCH2) 176

(m 2H CyCH2) 175 (m 1H CHCH2CH) 171 (m 2H CyCH2) 167 (m 2H CyCH2) 144 (qt 3JH-H = 111 Hz 3JH-H = 40 Hz 2H CH2CHCH2) 123 (m 2H CyCH2) 122 (m 2H

NH2CHCH2) 118 (m 2H CyCH2) 101 (m 2H CyCH2) 100 (m 1H CHCH2CH) 19F NMR

(377 MHz CD2Cl2) δ -1345 (m 2F o-C6F5) -1627 (t 3JF-F = 20 Hz 1F p-C6F5) -1663 (m

2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ -244 (d 1JB-H = 86 Hz BH) 13C1H NMR (101

MHz CD2Cl2) partial δ 639 (CHN) 406 (CH2CHCH2) 371 (CHCH2CH) 318 (CyCH2) 307

(NH2CHCH2) 249 (CyCH2) 248 (CyCH2) Anal calcd () for C31H25BF15N C 5264 H 356

N 198 Found C 5214 H 358 N 196

Synthesis of RRSSSSRR and SRSRRSRS-[(C13H22NH)B(C6F5)3] (231b) Compound 231b

was initially isolated from the pentane wash work-up for the synthesis of 231a Independent

synthesis of 231b was performed and the procedure is described

In a 4 dram vial tetradecahydroacridine (366 mg 0189 mmol) was dissolved in pentane (5

mL) at room temperature To the vial B(C6F5)3 (965 mg 0189 mmol) was added at once and

allowed to mix for 2 minutes The solution was filtered through a bed of Celite to yield a

colourless solution The vial was placed in a -30 ordmC freezer for 3 h and colourless crystals were

collected (973 mg 138 mmol 73) The isolated mixture of compound 231b consisted of a 11

mixture of RRSSSSRR and SRSRRSRS (C13H22NH)B(C6F5)3 only the diagnostic resonances of

RRSSSSRR-(C13H22NH)B(C6F5)3 have been reported

76

RRSSSSRR-[(C13H22NH)B(C6F5)3] 1H NMR (400 MHz CD2Cl2) δ 503 (br 1H NH) 353

(dm 3JH-H = 123 Hz 2H NCH) 214 (dm JH-H = 123 Hz 2H NH2CHCH2) 196 - 160 (m

6H CH2) 188 (m 2H CH2CHCH2) 177 (m 4H NH2CHCH2 and CHCH2CH) 149 - 111 (m

6H CH2) 19F NMR (377 MHz CD2Cl2) δ -1270 (m 1F o-C6F5) -1277 (m 1F o-C6F5) -

1281 (m 1F o-C6F5) -1291 (m 2F o-C6F5) -1302 (m 1F o-C6F5) -1558 (t 3JH-H = 21 Hz

1F p-C6F5) -1579 (t 3JH-H = 21 Hz 1F p-C6F5) -1589 (t 3JH-H = 21 Hz 1F p-C6F5) -1624

(m 1F m-C6F5) -1637 (m 3F m-C6F5) -1641 8 (m 1F m-C6F5) -1644 8 (m 1F m-C6F5)

11B NMR (128 MHz CD2Cl2) δ -318 (s BN) 13C1H NMR (101 MHz CD2Cl2) partial δ

630 (NCH) 359 (CHCH2CH) 356 (CH2CHCH2) 299 (NH2CHCH2) Anal calcd () for


[23-(C4H6Me)2NHNH2][HB(C6F5)3] (232) 23-Dimethylquinoxaline (0117 g 0740 mmol)

reaction time 96 h product (402 mg 437 mmol 59) The SRSSRSRR diastereomer was only

observed

1H NMR (400 MHz CD2Cl2) δ 643 (br 1H NH2) 592 (br 1H NH2) 349 (dm 3JH-H = 128

Hz 1H CH2CHN) 334 (br q 1JB-H = 94 Hz 1H BH) 326 (br m 2H NCHMe CH2CHN)

281 (dq 3JH-H = 123 Hz 64 Hz 1H NCHMe) 223 (dm JH-H = 128 Hz 1H CH2) 189 (dm

JH-H = 134 Hz 1H CH2) 179 (dm JH-H = 134 Hz 1H CH2) 162 (dm JH-H = 134 Hz 2H

CH2) 147 (m 1H CH2) 131 (m 1H CH2) 128 (d 3JH-H = 64 Hz 3H Me) 121 (d 3JH-H =

62 Hz 3H Me) 120 (m 1H CH2) (NH was not observed) 19F NMR (377 MHz C6D5Br) δ -



(dm 1JC-F = 234 Hz C6F5) 1384 (dm 1JC-F = 246 Hz C6F5) 1368 (dm 1JC-F = 247 Hz C6F5)

1232 (ipso-C6F5) 576 (CH2CHN) 563 (NCHMe) 541 (NCHMe) 519 (CH2CHN) 304

(CH2) 242 (CH2) 224 (CH2) 185 (CH2) 178 (Me) 151 (Me) Anal calcd () for


[23-(C4H6Ph)2NHNH2][HB(C6F5)3] (233) 23-Diphenylquinoxaline (0209 g 0740 mmol)

reaction time 96 h product (328 mg 0407 mmol 55) Crystals suitable for X-ray diffraction

were grown from a layered solution of dichloromethanepentane at RT Diastereomers

SRSSRSRR and RRRSSSSR are present in equal ratios The assigned diastereomers were

77

supported by 1H1H NOESY NMR spectroscopy Anal calcd () for C38H26BF15N2 C 5660

H 325 N 347 Found C 5611 H 313 N 321

SRSSRSRR-[23-(C4H6Ph)2NHNH2][HB(C6F5)3] 1H NMR (400 MHz C6D5Br) δ 763 (m 4H

Ph) 699 - 684 (m 6H Ph) 572 (br 2H NH2) 476 (d 3JH-H = 34 Hz 1H CHPh) 441 (d 3JH-H = 34 Hz 1H CHPh) 407 (br 1H NH) 356 (br q 1JB-H = 82 Hz 1H BH) 314 (td 3JH-H

= 102 Hz 3JH-H = 34 Hz 1H CH2CHN) 260 (m 3JH-H = 102 Hz 34 Hz 1H CH2CHN) 167

(m 1H CH2) 159 (m 1H CH2) 153 (m 1H CH2) 129 (m 1H CH2) 122 (m 2H CH2)




CF) 1385 (dm 1JC-F = 246 Hz CF) 1367 (dm 1JC-F = 248 Hz CF) 1362 (ipso-Ph) 1313

(Ph) 1301 (Ph) 1267 (Ph) 637 (CHPh) 619 (CHPh) 597 (CH2CHN) 561 (CH2CHN) 314

(CH2) 282 (CH2) 242 (CH2) 233 (CH2) (ipso-C6F5 was not observed)

RRRSSSSR-[23-(C4H6Ph)2NHNH2][HB(C6F5)3] 1H NMR (500 MHz CD2Cl2) δ 729 - 708

(m 10H Ph) 657 (br 2H NH2) 451 (dm 3JH-H = 102 Hz 1H CHPh) 429 (dm 3JH-H = 102

Hz 1H CHPh) 386 (dm 3JH-H = 107 Hz 1H CH2CHN) 366 (br 1H NH) 328 (br q 1JB-H =

82 Hz 1H BH) 268 (dm 3JH-H = 107 Hz 1H CH2CHN) 205 (m 1H CH2) 188 (m 2H

CH2) 178 (m 2H CH2) 157 (m 1H CH2) 145 (m 1H CH2) 130 (m 1H CH2) 19F NMR

(377 MHz C6D5Br) δ -1331 (m 2F o-C6F5) -1606 (t 3JF-F = 21 Hz 1F p-C6F5) -1643 (m

2F m-C6F5) 11B NMR (128 MHz C6D5Br) δ -238 (d 1JB-H = 82 Hz BH) 13C1H NMR (125

MHz CD2Cl2) δ 1479 (dm 1JC-F = 235 Hz CF) 1382 (dm 1JC-F = 246 Hz CF) 1366 (dm 1JC-F = 248 Hz CF) 1314 (ipso-Ph) 1304 (Ph) 1301 (ipso-Ph) 1293 (Ph) 1290 (Ph) 1286

(Ph) 1277 (Ph) 1274 (Ph) 1226 (ipso-C6F5) 655 (CHPh) 621 (CHPh) 581 (CH2CHN)

526 (CH2CHN) 308 (CH2) 245 (CH2) 229 (CH2) 188 (CH2)

[(C6H4)C7H12NH2][HB(C6F5)3] (234) 78-Benzoquinoline (133 mg 0740 mmol) reaction

time 48 h product (285 mg 407 mmol 55) Crystals of the SRRS isomer suitable for X-ray

diffraction were grown from a layered solution of bromobenzenepentane at -30 ordmC Crystals of

the SSRR isomer suitable for X-ray diffraction were grown from a layered solution of

dichloromethanepentane at -30 ordmC Anal calcd () for C31H19BF15N C 5309 H 273 N 200

Found C 5347 H 291 N 209

78

Isomer ratio by 1HNMR spectroscopy SRRS 80 (pale orange crystals) SSRR 20 (colourless

crystals)

SRRS-[(C6H4)C7H12NH2][HB(C6F5)3] (234a) 1H NMR (400 MHz CD2Cl2) δ 725 (td 3JH-H

= 77 Hz 4JH-H = 14 Hz 1H C6H4) 715 (d 3JH-H = 77 Hz 1H C6H4) 707 (d 3JH-H = 77 Hz

1H C6H4) 700 (t 3JH-H = 77 Hz 1H C6H4) 597 (br 2H NH2) 440 (d 3JH-H = 38 Hz 1H

NCH) 361 (dt JH-H = 131 Hz 3JH-H = 35 Hz 1H NCH(H)) 328 (m 1H NCH(H)) 314 (br q 1JB-H = 80 Hz 1H BH) 294 (dm 2JH-H = 172 Hz 1H C6H4-CH(H)) 285 (dm 2JH-H = 172 Hz

1H C6H4-CH(H)) 239 (m 1H CH2CHCH2) 200 - 188 (br m 6H PiperidineCyCH2) 19F NMR



MHz CD2Cl2) δ 1483 (dm 1JC-F = 235 Hz CF) 1383 (dm 1JC-F = 246 Hz CF) 1378

(quaternary C for C6H4-CHN) 1368 (dm 1JC-F = 248 CF) 1311 (C6H4) 1307 (C6H4) 1292

(C6H4) 1288 (quaternary C for C6H4-CH2) 1277 (C6H4) 1234 (ipso-C6F5) 605 (NCH) 479

(NCH2) 320 (CH2CHCH2) 286 (C6H4-CH(H)) 274 (PiperidineCH2) 225 (CyCH2) 184

(PiperidineCH2)

SSRR-[(C6H4)C7H12NH2][HB(C6F5)3] (234b) 1H NMR (400 MHz C6D5Br) partial δ 701

(m 1H C6H4) 699 (m 1H C6H4) 685 (m 1H C6H4) 675 (d 3JH-H = 77 Hz 1H C6H4) 350

(d 3JH-H = 104 Hz 1H NCH) 324 (br dm JH-H = 124 Hz 1H NCH(H)) 279 (m 1H

NCH(H)) 254 (m 1H C6H4-CH(H)) 242 (m 1H C6H4-CH(H)) 142 (m 2H CH2) 128 (m

2H CH2) 105 (m 1H CH2CHCH2) 083 (m 2H CH2) (NH2 was not observed) 13C1H

NMR (101 MHz C6D5Br) δ 1370 (quaternary C for C6H4-CHN) 1304 (C6H4) 1291 (C6H4)

1284 (quaternary C for C6H4-CH2) 1264 (C6H4) 1226 (C6H4) 629 (NCH) 474 (NCH2) 378

(CH2CHCH2) 291 (CH2) 288 (C6H4-CH(H)) 276 (CH2) 229 (CH2)

[(C5H3N)(CH2)2(C5H8NH)B(C6F5)2][HB(C6F5)3] (235) B(C6F5)3 (379 mg 0740 mmol) 110-

phenanthroline (667 mg 0370 mmol) reaction time 96 h product (283 mg 0270 mmol 73)

Crystals suitable for X-ray diffraction were grown from a layered solution of

tetrahydrofuranpentane at -30 ordmC Approximately 65 of the reaction mixture consisted of the

SRSRSR diastereomer

1H NMR (400 MHz CD2Cl2) δ 944 (br s 1H NH) 850 (dd JH-H = 47 Hz JH-H = 15 Hz 1H

C5H3N) 744 (dd JH-H = 78 Hz JH-H = 15 Hz 1H C5H3N) 722 (dd JH-H = 78 Hz JH-H = 47

79

Hz 1H C5H3N) 442 (d 3JH-H = 43 Hz 1H NCyCH) 342 (br 1H BH) 322 (dm 2JH-H = 138

Hz 1H NC(H)H) 291 (ddd 2JH-H = 138 Hz 3JH-H = 87 Hz 53 Hz 1H NC(H)H) 276 - 272

(m 2H C6H4-CH(H)) 212 (dm 3JH-H = 121 Hz 38 Hz 1H CH2CHCH2) 196 (m 1H CH2)

188 (m 1H CH2) 173 (m 1H CH2) 132 (dt 2JH-H = 140 Hz 3JH-H = 32 Hz 1H CH2) 091

(qd JH-H = 131 Hz 3JH-H = 38 Hz 1H CH2) 071 (qt JH-H = 137 Hz 3JH-H = 40 Hz 1H CH2)

19F NMR (377 MHz CD2Cl2) δ -1289 (m 2F B(C6F5)2o-C6F5) -1343 (m 6F HB(C6F5)3o-C6F5) -

1348 (m 2F B(C6F5)2o-C6F5) -1491 (t 3JF-F = 20 Hz 1F B(C6F5)2p-C6F5) -1511 (t 3JF-F = 20 Hz

1F B(C6F5)2p-C6F5) -1596 (m 4F B(C6F5)2m-C6F5) -1645 (t 3JF-F = 20 Hz 3F HB(C6F5)3p-C6F5) -

1676 (m 6F HB(C6F5)3m-C6F5) 11B NMR (128 MHz CD2Cl2) δ 391 (s BN) -254 (d 1JB-H =

93 Hz BH) 13C1H NMR (101 MHz CD2Cl2) δ 1484 (quaternary C for C5H3N) 1466

(quaternary C for C5H3N) 1448 (C5H3N) 1354 (C5H3N) 1260 (C5H3N) 581 (CyNCH) 451

(NC(H)H) 296 (CH2C(H)CH2) 241 (CH2) 218 (CH2) 210 (CH2) 206 (CH2) Anal calcd

() for C42H17B2F25N2 C 4822 H 164 N 268 Found C 4783 H 197 N 269

243 X-Ray Crystallography

2431 X-Ray data collection and reduction

Crystals were coated in Paratone-N oil in the glovebox mounted on a MiTegen Micromount and

placed under an N2 stream thus maintaining a dry O2-free environment for each crystal The

data for crystals were collected on a Bruker Apex II diffractometer The data were collected at

150(plusmn2) K for all crystals The frames were integrated with the Bruker SAINT software package

using a narrow-frame algorithm Data were corrected for absorption effects using the empirical

multi-scan method (SADABS)

2432 X-Ray data solution and refinement

Non-hydrogen atomic scattering factors were taken from the literature tabulations268 The heavy

atom positions were determined using direct methods employing the SHELXTL direct methods

routine The remaining non-hydrogen atoms were located from successive difference Fourier

map calculations The refinements were carried out by using full-matrix least squares techniques

on F minimizing the function ω (Fo-Fc)2 where the weight ω is defined as 4Fo22σ (Fo

2) and Fo

and Fc are the observed and calculated structure factor amplitudes respectively In the final

cycles of each refinement all non-hydrogen atoms were assigned anisotropic temperature factors

in the absence of disorder or insufficient data In the latter cases atoms were treated isotropically

80

C-H atom positions were calculated and allowed to ride on the carbon to which they are bonded

assuming a C-H bond length of 095 Aring H-atom temperature factors were fixed at 120 times the

isotropic temperature factor of the C-atom to which they are bonded The H-atom contributions

were calculated but not refined The locations of the largest peaks in the final difference Fourier

map calculation as well as the magnitude of the residual electron densities in each case were of

no chemical significance

81

2433 Selected crystallographic data

Table 24 ndash Selected crystallographic data for 24 24rsquo and 25

24 24rsquo 25

Formula C27H21B1F15N1 C27H13B1F15N1 C30H25B1F15N1

Formula wt 65526 64719 69532

Crystal system monoclinic orthorhombic monoclinic

Space group P2(1)c P2(1)2(1)2(1) P2(1)n

a(Aring) 97241(8) 116228(4) 126342(6)

b(Aring) 147348(12) 181284(7) 181939(8)

c(Aring) 188022(15) 236578(9) 128612(6)

α(ordm) 9000 9000 9000

β(ordm) 98826(4) 9000 90269(2)

γ(ordm) 9000 9000 9000

V(Aring3) 26621(4) 49848(3) 29563(2)

Z 4 8 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1635 1725 1562

Abs coeff μ mm-1 0169 0179 0157

Data collected 18591 28169 50674

Rint 00336 00297 00369

Data used 4685 8773 5207

Variables 401 793 424

R (gt2σ) 00361 00315 00352

wR2 00898 00758 00947

GOF 1007 1021 1024

82

Table 25 ndash Selected crystallographic data for 216a 218 and 219

216a 218 219


Formula wt 67325 67123 71533

Crystal system monoclinic monoclinic orthorhombic

Space group P2(1)c P2(1)n Pbca

a(Aring) 97677(6) 104368(7) 18886(4)

b(Aring) 147079(11) 93382(7) 16050(3)

c(Aring) 190576(14) 273881(18) 19128(4)

α(ordm) 9000 9000 9000

β(ordm) 98934(2) 96910(3) 9000

γ(ordm) 9000 9000 9000

V(Aring3) 27046(3) 26499(3) 5798(2)

Z 4 4 8

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1653 1683 16388

Abs coeff μ mm-1 0174 0177 0163


Rint 00432 00404 00662

Data used 6164 4676 6654


R (gt2σ) 00522 00496 00687

wR2 01387 01462 01912

GOF 1032 1041 10743

83

Table 26 ndash Selected crystallographic data for 220 222 and 224

220 222 (+05 CH2Cl2) 224 (+05 CH2Cl2)

Formula C33H25B1F15N1O1 C285H22B1Cl1F15N1O1 C355H22B1ClF15N1

Formula wt 74737 72573 79380

Crystal system orthorhombic orthorhombic monoclinic

Space group Pbca Pbca P2(1)n

a(Aring) 173531(15) 17750(5) 109902(9)

b(Aring) 161365(15) 16032(4) 151213(11)

c(Aring) 227522(17) 20783(6) 194765(15)

α(ordm) 9000 9000 90

β(ordm) 9000 96910(3) 92062(3)

γ(ordm) 9000 9000 90

V(Aring3) 63710(9) 5914(3) 32346(4)

Z 8 8 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 15582 16278 1630

Abs coeff μ mm-1 0154 0250 0235


Rint 00406 01159 00306

Data used 7321 5198 5688


R (gt2σ) 00413 00811 00495

wR2 01112 02505 01363

GOF 10647 10628 0936

84


225 227 (+1 C5H12) 228


Formula wt 62721 141861 66727

Crystal system triclinic monoclinic triclinic

Space group P-1 P2(1)n P-1

a(Aring) 101339(5) 137416(4) 95967(15)

b(Aring) 112923(6) 119983(4) 108364(15)

c(Aring) 118209(6) 191036(7) 14143(2)

α(ordm) 98563(2) 9000 75929(5)

β(ordm) 109751(2) 109317(2) 80009(6)

γ(ordm) 94983(2) 9000 76629(5)

V(Aring3) 124520(11) 297240(17) 13772(4)

Z 2 2 2

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1673 1585 1609

Abs coeff μ mm-1 0176 0158 0235


Rint 00211 00246 00351

Data used 4357 5230 4743


R (gt2σ) 00371 00324 00546

wR2 00964 00816 01728

GOF 1044 1014 1028

85

Table 28 ndash Selected crystallographic data for 229 230 and 231a

229 (+05 C6H5Br) 230 231a

Formula C36H255B1Br05F15N1 C28H21B1F15N1 C31H25B1F15N1

Formula wt 80784 66727 70733

Crystal system monoclinic triclinic monoclinic

Space group C2c P-1 P2(1)n

a(Aring) 201550(11) 97752(4) 112914(4)

b(Aring) 133628(11) 120580(4) 183705(7)

c(Aring) 266328(18) 121120(5) 145648(5)

α(ordm) 9000 102296(2) 9000

β(ordm) 111905(6) 100079(2) 90480(2)

γ(ordm) 9000 90901(2) 9000

V(Aring3) 66551(8) 137127(9) 302105(19)

Z 8 2 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1613 1616 1555

Abs coeff μ mm-1 0749 0165 0155


Rint 00530 00245 00383

Data used 7644 4841 7630


R (gt2σ) 00651 00362 00778

wR2 01802 00971 02335

GOF 1037 1036 1007

86

Table 29 ndash Selected crystallographic data for 231b 233 and 234a

231b (+05 C6H14) 233 234a (+1 CH2Cl2)

Formula C34H30B1F15N1 C38H26B1F15N2 C32H21B1Cl2F15N1

Formula wt 74840 80642 78621

Crystal system triclinic monoclinic monoclinic

Space group P-1 Pn C2c

a(Aring) 107250(6) 99895(4) 181314(6)

b(Aring) 112916(7) 115666(5) 135137(5)

c(Aring) 136756(8) 155410(6) 253612(9)

α(ordm) 70523(2) 9000 9000

β(ordm) 88868(2) 105054(2) 92594(2)

γ(ordm) 86934(2) 9000 9000

V(Aring3) 155914(16) 173405(12) 62077(4)

Z 2 2 8

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1594 1544 1677

Abs coeff μ mm-1 0155 0147 0327


Rint 00233 00381 00512

Data used 5479 8395 7383


R (gt2σ) 00371 00400 00816

wR2 01066 00893 02554

GOF 0926 1011 1024

87

Table 210 ndash Selected crystallographic data for 234b and 235

234b 235 (+1 C4H8O +1 CH2Cl2)

Formula C31H19B1F15N1 C47H27B2Cl2F25N2O1

Formula wt 70128 120323

Crystal system monoclinic triclinic

Space group P2(1)c P-1

a(Aring) 100455(5) 113115(7)

b(Aring) 118185(5) 117849(8)

c(Aring) 245940(11) 188035(12)

α(ordm) 9000 83850(3)

β(ordm) 96724(2) 88364(3)

γ(ordm) 9000 69766(3)

V(Aring3) 28998(2) 23383(3)

Z 4 2

Temp (K) 150(2) 150(2)

d(calc) gcm-3 1606 1709

Abs coeff μ mm-1 0161 0281

Data collected 20742 36083

Rint 00342 00265

Data used 5101 8235

Variables 433 712

R (gt2σ) 00438 00473

wR2 01153 01198

GOF 1012 1015

88

Chapter 3 Enabling Catalytic Ketone and Aldehyde Hydrogenation

with Frustrated Lewis Pairs

31 Introduction

The reduction of carbonyl substrates such as aldehydes ketones esters acids and anhydrides to

alcohols is one of the most fundamental and widely used reactions in synthetic chemistry269

Sodium borohydride lithium aluminum hydride and other stoichiometric reducing agents56 224

serve adequately for laboratory scale syntheses however in an industrial setting the process

demands for a more clean environmentally benign and cost-effective procedure More desirable

methods involving H2 gas or transfer hydrogenation have proven practical and circumvent the

work-up operations required for stoichiometric reagents

Heterogeneous catalysts based on PdC and PtC are certainly atom economic however some of

these catalysts are not suitable in cases where mild conditions functional group tolerance and

chemoselectivity are required Therefore substantial research has been directed towards

homogeneous catalysts involving Ir237 Rh239 Ru238 Cu269 and Os238 complexes including metal-

immobilized systems269

Despite the power of these technologies research efforts motivated by cost toxicity and low

abundance have focused on the development of first-row transition metal catalysts based on Fe

and Co210 221 Also on-going interest in the field has been devoted to the discovery of new

asymmetric hydrogenation catalysts131 208-209 263-264136 213-214 270-271 in addition to transfer

hydrogenation via the Meerwein-Ponndorf-Verley reduction procedure216

311 FLP reactivity with unsaturated C-O bonds

In 1961 Walling and Bollyky reported the first metal-free hydrogenation system demonstrating

the reduction of the non-enolizable ketone benzophenone using H2 (100 atm) and tBuOK as the

catalyst at 200 degC175-176 While more recently metal-free reductions have been demonstrated

under more mild conditions using frustrated Lewis pairs (FLPs) These combinations of

sterically encumbered main group Lewis acids and bases have been shown to effect the catalytic

hydrogenation of a variety of unsaturated organic substrates Noticeably absent from these

substrates are ketones and aldehydes This is perhaps surprising given the precedence of catalytic

89

hydrosilylation of ketones established by Piers182 Moreover a number of groups have

demonstrated the ability of FLPs to effect the reduction of CO2 using H2259 silanes169 180 182

boranes111 163 272 or ammonia-borane273 as sources of the reducing equivalents The limited

attention to hydrogenation of ketones and aldehydes has been attributed to the high oxophilicity

of electrophilic boranes72 171 Indeed in an earlier report Erker and co-workers described the

irreversible capture of benzaldehyde and trans-cinnamaldehyde (Scheme 31 top) as well as the

14-addition of conjugated ynones by the intramolecular PB FLP Mes2PCH2CH2B(C6F5)2173 A

number of stoichiometric reductions have also been reported using H2 activated PB FLPs with

an example shown in Scheme 31 (bottom)94 173


(top) stoichiometric reduction of benzaldehyde using Mes2P(H)CH2CH2BH(C6F5)2 (bottom)

Nonetheless the group of Privalov has computed an energetically viable mechanism for ketone

reduction suggesting a process analogous to imine hydrogenation and carbonyl hydrosilylation

using B(C6F5)3 as the catalyst274 Attempts to realize this prediction experimentally have been

unsuccessful Repo et al described the stoichiometric reaction of aromatic ketones with B(C6F5)3

effecting deoxygenation of the ketone to afford (C6F5)2BOH C6F5H and the corresponding aryl

alkane (Scheme 32 a)178 Furthermore the Stephan group found that similar reduction of alkyl

ketones gave borinic esters via H2 activation hydride delivery and protonation of a C6F5 group

(Scheme 32 b)275

90


ketones to borinic esters (b)

Similar degradation of B(C6F5)3 via B-C bond cleavage affording CH3OB(C6F5)2 and C6F5H was

reported by Ashley and OrsquoHare in their efforts to reduce CO2 in the presence of H2 to CH3OH259

Due to the instability of B(C6F5)3 in these transformations Wang et al approached the catalytic

ketone hydrogenation challenge computationally suggesting that a bifunctional amine-borane

FLP catalyst would be viable276 Interestingly Du et al have taken a detour from direct FLP

hydrogenation of carbonyl groups reporting the catalytic hydrogenation of silyl enol ethers using

a chiral borane to obtain a variety of optically active secondary alcohols after workup (Scheme

33)277


alcohols

Reaction of main group species with other unsaturated C-O functionalities namely carbon

monoxide is also limited H C Brown established the synthesis of tertiary alcohols by

91

carbonylation of trialkylboranes using carbon monoxide278 although the analogous reactivity by

B-H boranes proved challenging279-282

Recently however Erker et al described the stoichiometric reduction of carbon monoxide by the

reaction of intramolecular PB FLPs and the hydroboration reagent HB(C6F5)2 to yield epoxy-

borate species (Scheme 34 top)118-119 283 Simultaneously the Stephan group exploited the

reaction of a 12 mixture of tBu3P and B(C6F5)3 with syn-gas (CO and H2) to result in sequences

of stoichiometric reactions eventually affording the borane-oxyborate derivative

(C6F5)2BCH(C6F5)OB(C6F5)3 a product of C-O bond cleavage (Scheme 34 bottom)117


reaction of tBu3P and B(C6F5)3 with COH2 to generate (C6F5)2BCH(C6F5)OB(C6F5)3 (bottom)

The main group reduction of carbonyl groups has been limited to stoichiometric reactions with

classic hydride reagents In this chapter a remarkably simple approach to the metal-free

hydrogenation of ketones and aldehydes is reported using FLP catalysts derived from B(C6F5)3

and ether The hydrogenation concept was extended towards a heterogeneous avenue using

catalysts derived from the combination of polysaccharides or molecular sieves with B(C6F5)3

Moreover the catalytic reductive deoxygenation of aryl ketones is achieved in the case of

molecular sieves

92


321 B(C6F5)3 decomposition pathway in C=O hydrogenation reactions

Heating a toluene solution of 5 mol B(C6F5)3 and 4-heptanone under H2 (60 atm) at 80 degC

yielded complete conversion of B(C6F5)3 to the borinic ester Pr2CHOB(C6F5)2 with concurrent

liberation of C6F5H The remaining 95 of the initial ketone was unaltered This observation

illustrates that borane and ketone act as a FLP to heterolytically cleave H2 affording nominally

[Pr2COH][HB(C6F5)3] At this stage the hydride is presumed to reduce the carbonyl fragment to

generate 4-heptanol which subsequently decomposes B(C6F5)3 to Pr2CHOB(C6F5)2 and C6F5H

It is important to note that the above example of rapid and facile decomposition of B(C6F5)3 to

borinic ester stands in contrast to an observation illustrated in Chapter 2 In this case the CH3OH

generated from ammonium protonation of [CH3OB(C6F5)3]- does not decompose B(C6F5)3 rather

under an atmosphere of H2 the resulting amine and B(C6F5)3 heterolytically split H2 to give the

ammonium [HB(C6F5)3] product (Scheme 35) Thus this observation led to the proposal of two

plausible borane decomposition pathways in ketone hydrogenation reactions

Scheme 35 ndash Activation of H2 by amineborane FLP while in the presence of CH3OH

In both pathways the reaction initiates with heterolytic H2 splitting by the ketone and B(C6F5)3

to give the ionic pair [R2COH][HB(C6F5)3] (Scheme 36) At this point the reaction could follow

a pathway in which hydride is transferred from the [HB(C6F5)3]- anion to the activated carbonyl

group generating alcohol and B(C6F5)3 both of which further react to give borinic ester and

C6F5H (Scheme 36 Pathway 1) The second pathway suggests the borane undergoes

protonolysis by the [R2COH]+ cation cleaving a C6F5 group to form HB(C6F5)2 and C6F5H whilst

regenerating the ketone The borane then undergoes hydroboration of the carbonyl group to

afford the borinic ester (Scheme 36 Pathway 2)

93


hydrogenation

To test Pathway 1 B(C6F5)3 was added to excess 4-heptanol (10 eq) and heated to 80 degC for 12

h This resulted in no reaction beyond formation of the alcohol-borane adduct

Pr2CHOHmiddotB(C6F5)3 as evidenced by the 11B and 19F NMR spectra (11B δ 197 ppm 19F δ -

1326 -1552 -1628 ppm) On the other hand stoichiometric and 5 mol combinations of

HB(C6F5)2 with 4-heptanone formed the new hydroboration species Pr2CHOB(C6F5)2 after 10

min at RT In addition to the characteristic methine multiplet observed at 405 ppm in the 1H

NMR spectrum 11B NMR spectroscopy gave a broad resonance at 394 ppm with 19F NMR

signals at -1325 -1498 and -1613 ppm representing the three-coordinate boron centre These

experiments provide evidence for Pathway 2 resulting in decomposition of B(C6F5)3 during

ketone hydrogenation

322 B(C6F5)3 catalyzed carbonyl hydrogenation in ethereal solvents

To avoid this degradation pathway an alternative FLP is required This system must be basic

enough to effect H2 activation and stabilize the acidic proton by electrostatic interactions In this

regard the Stephan group previously reported that the ethereal oxygen of the borane-oxyborate

derivative (C6F5)2BCH(C6F5)OB(C6F5)3 is sufficiently Lewis basic to activate H2 with the

coordinating B(C6F5)2 group117 Subsequently the combination of weak Lewis bases such as

Et2O electron deficient triarylphosphines and diaryl amines were shown to be sufficiently basic

for both H2 activation and catalytic reduction of olefins99 257 In the case of Et2O DFT

calculations highlighted that solvation of the protonated ether by a second equivalent of Et2O can

significantly stabilize the proton by hydrogen-bonding interactions

94

To probe the viability of using Et2O in carbonyl reductions a d8-toluene solution of 5 mol

B(C6F5)3 was combined with a 51 ratio of Et2O4-heptanone and heated to 70 degC under H2 (4

atm) Monitoring the J-Young experiment by high temperature 1H NMR spectroscopy showed

gradual hydrogenation of the ketone yielding approximately 50 of 4-heptanol after 12 h The 1H NMR spectrum shows a distinct quintet at 345 ppm diagnostic of the hydrogenated C=O

fragment forming a C-H bond in addition to the multiplets at 128 and 080 ppm (Figure 31)

Increasing the H2 pressure to 60 atm improved the yield of 4-heptanol to 70



intervals Starting material 4-heptanone ($) product 4-heptanol ()

Alternatively incrementing the ratio of Et2O to 4-heptanone resulted in increased yields in

which case a 81 ratio of Et2O4-heptanone in toluene gave 97 conversion to 4-heptanol after

12 h (Figure 32) The continuous improvement in alcohol yield was a direct result of gradual

preservation of the borane catalyst in the reaction as the Et2O concentration was increased

Employing identical conditions but using Et2O as the solvent resulted in the quantitative

formation of 4-heptanol after 12 h Similarly employing iPr2O as the solvent in analogous

$ $ 12

11

10

9

8

7

6

5

4

3

2

1

95

hydrogenations gave quantitative yields of 4-heptanol The use of Ph2O and TMS2O resulted in

yields of 44 and 42 in the same time frame (Table 31 entry 1)


heptanone to 4-heptanol

Using this FLP hydrogenation protocol a range of ketone substrates were treated with 5 mol

B(C6F5)3 in Et2O iPr2O Ph2O or TMS2O and heated for 12 h at 70 degC under H2 (60 atm) The

substrates investigated included several alkyl ketones (Table 31 entries 1 - 9) an aryl ketone

(Table 31 entry 10) benzyl ketones with substituents including F and CF3 groups (Table 31

entry 11 - 15) cyclic ketones including L-menthone and cyclohexanone (Table 31 entries 16

and 17) as well as the aldehyde cyclohexanal (Table 31 entry 18) Evaluating these reductions

by 1H NMR spectroscopy showed yields ranging between 32 - gt99 and isolated yields up to

91 for the reactions carried out in Et2O and iPr2O (Table 31) 1H NMR spectra of the alcohols

displayed characteristic multiplets at about 4 ppm assignable to the distinctive methine protons

with corresponding 13C1H resonances observed at ca 70 ppm as expected

These reactions could also be performed on a larger scale For example 100 g of 4-heptanone

was quantitatively converted to 4-heptanol using 5 mol B(C6F5)3 in Et2O and the alcohol

product was isolated in 87 yield

96

Table 31 ndash Catalytic hydrogenation of ketones and aldehydes in ethereal solvents

Conversion (Isolated yields)

Entry R R1 Et2O iPr2O Ph2O TMS2O

1 n-C3H7 n-C3H7 gt99 (91) gt99 70 52

2 Me iPr gt99 (76) gt99 44 42

3 Me CH2tBu gt99 gt99 (90) 22 14

4 Me n-C5H11 93 (85) 50 (43) 58 41

5 Me CH2Cl gt99 (85) gt99 91 82

6 Me Cy 77 - - -

7 Et iPr gt99 gt99 (89) - trace

8 Et n-C4H9 gt99 (87) 95 44 38

9 Et CH2iPr 40 47 - -

10 Me Ph 90 69 (52) trace trace

11 Et CH2Ph gt99 (84) 97 trace trace

12 Me n-CH2CH2Ph gt99 (84) 69 58 24

13 Me CH2(o-FC6H4) 97 gt99 (90) trace trace

14 Me CH2(p-FC6H4) gt99 gt99 (90) trace trace

15 Me CH2(m-CF3C6H4) gt99 gt99 (88) 55 trace

16 -(CH2)5- 53 41 - -

17 -(2-iPr-5-Me)C5H8- gt99 (88) 89 47 45

18 Cy H 32 - - -

(-) Reaction was not performed

323 Proposed mechanism for the catalytic hydrogenation of ketones using B(C6F5)3 in ethereal solvents

The mechanism of these reactions is thought to be analogous to that previously described for

imine hydrogenations92 In the present case ether combines with the borane in equilibrium

97

between the classical Lewis acid-base adduct and the corresponding FLP in which the latter

effects the heterolytic cleavage of H2 The resulting protonated ether then associates with ketone

via a hydrogen-bonding interaction284-285 activating the carbonyl fragment for hydride transfer

from the [HB(C6F5)3]- anion Subsequent protonation of the generated alkoxide yields the

product alcohol while liberating etherB(C6F5)3 to further activate H2 (Scheme 37) It has been

experimentally proven that activation of the carbonyl fragment is required prior to hydride

delivery as a 11 combination of 4-heptanone and [NEt4][HB(C6F5)3] do not result in reactivity

Scheme 37 ndash Proposed mechanism for catalytic ketone hydrogenation in ethereal solvents

The possibility of initial H2 activation by ketoneborane combinations cannot be dismissed

however the proposed mechanism is based on the large excess of ether in comparison to ketone

In support of this proposed mechanism the activation of H2 by ethereal oxygen Lewis bases and

boranes have been described to protonate imines and alkenes en route to the corresponding

hydrogenated products257 286

324 Structural analogue of the proposed intermediate in the ketone hydrogenation mechanism

The proposed H-bonding ether-ketone intermediate was further probed by the stoichiometric

reaction of a toluene solution of Jutzirsquos acid [(Et2O)2H][B(C6F5)4]287 with 1-phenyl-2-butanone

and iPr2O After heating the reaction at 70 degC for 2 h a white crystalline solid 31 was isolated in

87 yield (Scheme 38) The 1H NMR spectrum of 31 showed a broad singlet at 1152 ppm

suggesting a proton involved in hydrogen-bonding Resonances attributable to both 1-phenyl-2-

butanone and iPr2O were unambiguously present although these shifts were deshielded in

98

comparison to the individual components These data in addition to the definite presence of the

[B(C6F5)4]- anion as evidenced by 11B and 19F NMR spectroscopy lead to the assignment of 31

as [(iPr2O)H(O=C(CH2Ph)CH2CH3)][B(C6F5)4]

Scheme 38 ndash Synthesis of 31

The structure of 31 was unambiguously confirmed by single crystal X-ray crystallography

(Figure 33) The molecular structure of this salt shows the proximity of the ketone and ether in

the cation with an O-O separation of 2534(3) Aring Location and complete refinement of the proton

in the cation shows it is associated with the ether oxygen and hydrogen-bonded to the ketone

with O-H distances of 104(2) and 154(2) Aring respectively The resulting angle at H is 1581(3)deg

consistent with that typically seen for hydrogen-bonding interactions288-289 The isolation of 31

provides a direct structural analogue of the proposed intermediate in the ketone hydrogenation

mechanism

The equilibrium position of the generated proton is predicted to favour the ether oxygen atom

where the unshared electron pair is sp3 hybridized making the ether oxygen more basic than the

carbonyl where the unshared pair is sp2 hybridized This is also in agreement with predicted pKa

values of protonated ether and ketone289

Figure 33 ndash POV-Ray depiction of 31

99

325 Other hydrogen-bond acceptors for carbonyl hydrogenations

By analogy to the proposed mechanism with ethereal solvents ketone hydrogenations were

explored with crown ethers in toluene To this end combinations of 5 and 10 mol of 12-crown-

4 18-crown-6 and benzo-12-crown-4 were used with 5 mol B(C6F5)3 and 4-heptanone

However in all cases only trace amounts of 4-heptanol was observed Similar to the results in

ethereal solvents these hydrogenation results could possibly be improved by using an excess of

the crown ether On the other hand inefficient hydrogenation could result due to the multiple

stabilizing hydrogen bonds with the crown (OCH2)n groups

Alternative oxygen containing solvents THF and tetrahydropyran were tested using the

hydrogenation protocol in both cases however catalysis was not observed This result could be

explained by the difference in steric hindrance of the two solvents in comparison to Et2O and

iPr2O Nonetheless performing the hydrogenations in 24-dimethylpentan-3-ol gave the

quantitative reduction of 4-heptanone after 12 h at 70 degC This result led to the proposal that

chiral alcohols could possibly be used as the solvent to induce asymmetric reduction of ketones

Thus testing this theory using enantiomerically pure alcohols (S)-2-octanol (R)-2-octanol (R)-

(+)-1-phenyl-1-butanol (S)-(+)-12-propanediol and (R)-(+)-11rsquo-bi(2-naphthol) the prochiral

ketone substrates in Table 31 entries 2 - 10 were hydrogenated although in all cases the

products were obtained as racemic mixtures

326 Other boron-based catalysts for carbonyl hydrogenations

While exploring other boron-based catalysts in carbonyl reductions borenium cation-based FLP

hydrogenation catalysts105 derived from carbene-stabilized 9-borabicyclo[331]nonane (9-

BBN) were tested in lieu of B(C6F5)3 (Figure 34) However at 70 degC (temperature required for

hydrogenation when using B(C6F5)3) the borenium cation catalysts were found to decompose to

unknown products thereby not resulting in any reactivity

100


reactions [B(C6F5)4]- anions have been omitted

327 Alternative approach to catalytic ketone hydrogenation using a B(C6F5)3-assisted mechanism

Reflecting back on a key result presented in Chapter 2 an alternative mechanism was applied to

successfully achieve B(C6F5)3 catalyzed ketone hydrogenation This finding demonstrates the

participation of the [CH3OB(C6F5)3]- anion and B(C6F5)3 in H2 activation forming CH3OH and

[HB(C6F5)3]- (Scheme 39) thereby signifying the lability of B(C6F5)3-alkoxide bonds

Scheme 39 ndash Example demonstrating lability of a B(C6F5)3-alkoxide bond

Taking lability of the presented B-O bond into consideration a two component catalyst system

comprising of B(C6F5)3 and [NEt4][HB(C6F5)3] was conceptualized for ketone hydrogenation In

this regard the B(C6F5)3 catalyst is expected to coordinate to the carbonyl group activating it for

hydride delivery from [NEt4][HB(C6F5)3] This will consequently generate B(C6F5)3 and

B(C6F5)3-alkoxide wherein similar to Scheme 39 will react with H2 to form alcohol and

regenerate the catalysts

The proposed catalytic system was examined by combining 5 mol B(C6F5)3 and 5 mol

[NEt4][HB(C6F5)3] with 4-heptanone in toluene and heating at 80 degC under H2 (60 atm) After 12

h 1H NMR data revealed catalyst turnover giving 92 conversion to the product 4-heptanol

(Table 32 entry 1) It is important to note that under similar reaction conditions the

combination of ketone with [NEt4][HB(C6F5)3] does not give any reactivity while B(C6F5)3 alone

is decomposed to the borinic ester

101

Using this hydrogenation protocol dialkyl substituted ketones gave the corresponding alcohols

in 40 - 99 conversions by 1H NMR spectroscopy (Table 32 entries 2 - 6) Conversions were

dramatically reduced for methyl cyclohexyl ketone (Table 32 entry 7) aryl and benzyl

substituted ketones (Table 32 entries 8 - 10) benzylacetone (Table 32 entry 11) in addition to

the cyclic ketones cyclohexanone and 2-cyclohexen-1-one (Table 32 12 and 13) Interestingly

reduction of L-menthone produced the respective alcohol product in 62 by 1H NMR

spectroscopy (Table 32 entry 14)

Table 32 ndash FLP mediated catalytic ketone hydrogenation using B(C6F5)3[NEt4][HB(C6F5)3]

Entry R R1 Conversion

1 n-C3H7 n-C3H7 92

2 Me iPr 57

3 Me CH2Cl gt99

4 Me 2-butyl 53

5 Et iPr gt99

6 Et CH2iPr 40

7 Me Cy 18

8 Me Ph 20

9 Ph Ph 20

10 Et CH2Ph 25

11 Me n-CH2CH2Ph 25

12 -(CH2)5- 28

13 -(CH2)3CH=CH- 0

14 -(2-iPr-5-Me)C5H8- 62

All conversions are determined by 1H NMR spectroscopy

102

3271 Proposed mechanism for ketone hydrogenation using the B(C6F5)3[NEt4][HB(C6F5)3] catalyst system

The mechanism of this reaction is thought to proceed by initial coordination of the Lewis acid

B(C6F5)3 to the carbonyl group assisting hydride transfer from [NEt4][HB(C6F5)3] resulting in

liberation of B(C6F5)3 and generation of [NEt4][RR1C(H)OB(C6F5)3] in which the alkoxide

anion is coordinated to B(C6F5)3 (Scheme 310) This combination of [RR1C(H)OB(C6F5)3]-

anion and B(C6F5)3 act as a FLP to activate H2 and dissociate the alcohol while simultaneously

regenerating B(C6F5)3 and [NEt4][HB(C6F5)3] By 1H NMR spectroscopy the [NEt4]+ cation

does not appear to participate in the reaction

R R1

OH

H

B(C6F5)3

R R1

O

+

B(C6F5)3

R R1

O NEt4

HB(C6F5)3

NEt4

B(C6F5)3

B(C6F5)3

R R1

O

05 H2

05 H2

H+ from H2 activation

H- from H2 activation



In comparison to carbonyl hydrogenations in ethereal solvents the presented Lewis acid-assisted

mechanism has resulted in lower alcohol yields due to steric hindrance of the substrate Lewis

base preventing adequate coordination to the Lewis acid and consequently inefficient activation

of the carbonyl bond Additionally the steric hindrance of the alkoxyborate anion resulting from

hydride delivery slows down the H2 activation step allowing unreacted B(C6F5)3 and ketone to

activate H2 giving the corresponding borinic ester

328 Attempted hydrogenation of other carbonyl substrates and epoxides

Carbonyl reductions employing either the etherB(C6F5)3 FLP catalyst or the two component

catalyst species B(C6F5)3[NEt4][HB(C6F5)3] were unsuccessful for the ketones

diphenylcyclopropenone (ndash)-fenchone 25-hexanedione 6-methyl-35-heptadien-2-one

103

cyclohexane-14-dione 1-acetyl-1-cyclohexene 13-difluoroacetone 2-acetylthiophene 44-

dimethoxybutan-2-one aldehydes 5-methylthiophene-2-carboxaldehyde esters ethyl acetate

ethylchloroformate methylbenzoate ethylpyruvate phenyl acetate carboxylic acids isobutyric

acid pivalic acid 3-phenylpropanoic acid carbonates ethylene carbonate diethyl carbonate

and NN-diethylpropionamide Exposure of diethylmaleate to the hydrogenation conditions only

led to reduction of the C=C double bond

Similar treatment of the epoxides styrene oxide and trans-stilbene oxide were found to undergo

the well-documented Lewis acid catalyzed Meinwald rearrangement forming 2-

phenylacetaldehyde and 22-diphenylacetaldehyde respectively Selectivity of the aldehyde

products is determined by formation of the most stable carbenium intermediate followed by a

hydride shift (2-phenylacetaldehyde) or substituent shift (22-diphenylacetaldehyde)290-291

Moreover an attempt at extending this reduction procedure to the greenhouse gas CO2 was not

successful In this sense a J-Young tube consisting of B(C6F5)3 and 10 eq of Et2O was

pressurized with CO2H2 and heated at temperatures up to 80 degC Multinuclear NMR data only

revealed resonances corresponding to the Et2O-B(C6F5)3 adduct

329 FLPs comprised of B(C6F5)3 with polysaccharides or molecular sieves as Lewis bases

As presented in Section 322 judicious choice of the FLP catalyst derived from ether and

B(C6F5)3 gives catalytic hydrogenation of carbonyl substrates to their corresponding alcohols

The protonated ether solvent is proposed to hydrogen bond with the ketone substrate stabilizing

the Broslashnsted acidic proton while activating the carbonyl fragment to accept hydride from the

[HB(C6F5)3]- anion (Scheme 37)

Continued interest in ketone and aldehyde hydrogenation reactions led to the investigation of

potential oxygen-rich materials that will mimic ethereal solvents permitting catalytic

hydrogenation in a non-polar solvent To this end FLP hydrogenations were performed in

toluene using the Lewis acid B(C6F5)3 with the addition of heterogeneous Lewis bases including

cyclodextrins (poly)saccharides or molecular sieves (MS) with the formula

Na12[(AlO2)12(SiO2)12] (Figure 35)

104


3291 Polysaccharides as heterogeneous Lewis bases

In probing this investigation α-cyclodextrin (α-CD) an oligosaccharide formed of six

glucopyranose units (Figure 35 a) was initially tested in H2 activation In this regard 5 mol

B(C6F5)3 and α-CD were combined in d8-toluene and exposed to HD gas (1 atm) in a J-Young

tube at 60 degC (Figure 36 a) 1H NMR analysis after 1 h revealed signals for H2 resulting from

isotope equilibration thereby signifying the viability of H2 activation between B(C6F5)3 and the

oxygen donors of α-CD (Figure 36 b) Furthermore the 11B and 19F NMR spectra indicated

signals corresponding to unaltered B(C6F5)3 thus suggesting a remarkably simple and

inexpensive H2 activation FLP catalyst It is important to note that B(C6F5)3 or α-CD alone do not

effect HD activation


mol B(C6F5)3 and α-CD after 12 h at 60 degC (b) 1H δ 456 (H2) 452 1JHD = 423 Hz (HD)

To assess the unprecedented FLP system in carbonyl hydrogenation catalysis the ketone 3-

methyl-2-butanone was combined with an equivalent of α-CD and 5 mol B(C6F5)3 in toluene

and heated at 60 degC under H2 (60 atm) After 12 h quantitative reduction to the product 3-

methyl-2-butanol was evidenced by 1H NMR spectroscopy revealing a diagnostic multiplet at

327 ppm corresponding to the product CH group and broad singlet at 182 ppm assignable to the

a) b)

a)

b)

105

OH group (Table 33 entry 1) Repeating the reaction in the absence of H2 does not lead to

reduction of the substrate thus eliminating the possibility of transfer hydrogenation from α-CD

Under similar conditions a series of methyl alkyl (Table 33 entries 2 - 6) and dialkyl ketones

(Table 33 entries 7 - 9) aryl (Table 33 entries 10 - 14) benzyl (Table 33 entries 15 - 19) and

cyclic ketones (Table 33 entries 20 - 22) were hydrogenated in high yields In addition the

catalytic reduction of aldehydes was similarly performed to give the corresponding primary

alcohols (Table 33 entries 23 - 25) The 1H NMR spectra for all products displayed a

characteristic resonance at about 4 ppm diagnostic of CH and CH2 protons for ketone and

aldehyde reductions respectively and the corresponding 13C1H resonances were observed at

ca 70 ppm

The efficient nature of these catalytic reactions imply that B(C6F5)3 and the oxygen atoms of α-

CD act as a FLP to activate H2 initiating hydrogenation catalysis Selective silylation of α-CD at

the 2- and 6-hydroxy positions of the glucose units gave the toluene soluble product hexakis[26-

O-(tert-butyldimethylsilyl)]-α-cyclodextrin292 This derivatization was found to have a marginal

influence on catalysis forming 3-methyl-2-butanol in 70 yield after 12 h at 60 degC Moreover

the hydrogenation protocol was further investigated using the heterogeneous Lewis bases β and

γ-CD oligosaccharides of seven and eight glucopyranose units respectively and the

(poly)saccharides maltitol and dextrin Hydrogenation results are summarized in Table 33

Taking into account that cyclodextrins are used as chiral stationary phases in separation of

enantiomers the prochiral substrates of Table 33 were analyzed by chiral GC However in all

cases the products were found as racemic mixtures

106


Entry R R1 α-CD β-CD γ-CD Maltitol Dextrin MS

1 Me iPr gt99 79 77 62 81 gt99

2 Me 2-butyl gt99 74 72 46 75 gt99

3 Me CH2tBu gt99 52 41 40 53 gt99

4 Me CH2Cl gt99 gt99 trace 51 trace 80

5 Me Cy gt99 81 62 31 64 gt99

6 Me n-C5H11 gt99 63 56 36 73 gt99

7 Et iPr gt99 75 75 69 80 gt99

8 Et n-C4H9 95 93 95 58 gt99 93

9 n-C3H7 n-C3H7 gt99 - - - - 92

10a Me Ph 30 13 15 10 27 trace

11 CH2CH2Cl Ph 54 - - - - 50

12 CF3 Ph 20 - - - - 20

13 Me o-CF3C6H4 trace - - - - 25

14 Me p-MeSO2C6H4 60 - - - - 97

15 Me n-CH2CH2Ph gt99 58 90 38 trace gt99

16 Me CH2(o-FC6H4) 75 70 69 66 34 gt99

17 Me CH2(p-FC6H4) gt99 49 31 55 48 gt99

18 Me CH2(m-CF3C6H4) gt99 gt99 62 43 92 gt99

19 Et CH2Ph gt68 20 31 28 46 gt99

20 -(CH2)5- gt99 72 65 68 90 gt99

21b -(CH2)3CH=CH- 67 trace trace trace trace 82

22 -(2-iPr-5-Me)C5H8- gt99 70 60 60 80 gt99

23 Cy H 10 - - - - 44

24 Ph2CH H 47 - - - - 86

25 PhCH(Me) H 20 - - - - 35

a Reported yields are for phenylethanol b Product is cyclohexanol Isolated yields are reported for α-CD and MS

107

3292 Molecular sieves as heterogeneous Lewis bases

The presented (poly)saccharides could be conveniently replaced with the ubiquitous laboratory

drying agent MS293 as HD isotope equilibration experiments evidenced the formation of H2

when exposed to a d8-toluene suspension of MS and B(C6F5)3 It is noteworthy however that

such equilibration was not observed in the absence of B(C6F5)3

Using MS as the heterogeneous Lewis base 5 mol B(C6F5)3 catalyzed the hydrogenation of

ketone and aldehyde substrates reported in Table 33 These reductions could also be performed

on an increased scale with consecutive recycling of the MS For example 100 g of 4-heptanone

in toluene was treated with 5 mol of the catalyst B(C6F5)3 and MS yielding quantitative

conversion to 4-heptanol which was isolated in 95 yield The sieves were washed with solvent

and recombined with borane and ketone in three successive hydrogenations without loss of

activity

Speculation of physisorbed B(C6F5)3 onto MS was probed by reusing filtered sieves that were

washed with toluene without further addition of B(C6F5)3 This gave 30 reduction of 4-

heptanone suggesting that while there is some physisorption it is not sufficient to provide a

significant degree of catalysis

3293 Reductive deoxygenation of alkyl aryl ketones and diaryl ketones

In an effort to reduce the aryl alkyl ketone acetophenone the above protocol using α-CD was

employed for 12 h at 70 degC under H2 (60 atm) 1H NMR data revealed ca 60 consumption of

acetophenone resulting in the formation of two products in almost equal ratios The distinct

quartet at 424 ppm broad singlet at 342 ppm and doublet at 102 ppm were consistent with the

hydrogenated product phenylethanol (Scheme 311) The 1H NMR spectrum of the second

product gave three separate doublet of doublets with olefinic chemical shifts observed at 652

556 and 504 ppm with each signal integrating to one proton Mass spectroscopy confirmed this

species to be styrene derived from reductive deoxygenation (Scheme 311) The reaction was

repeated using MS giving styrene in a significantly improved 92 yield (Table 34 entry 1)

108

Scheme 311 ndash Catalytic hydrogenation and reductive deoxygenation of acetophenone

To probe this deoxygenation further the ketone 3rsquo-(trifluoromethyl)acetophenone was treated

with 5 mol B(C6F5)3 in toluene and added to a suspension of MS and heated for 12 h at 70 degC

under H2 (60 atm) This resulted in formation of the deoxygenated product 3-

(trifluoromethyl)styrene in 95 yield (Table 34 entry 2) while remainder of the reaction

mixture consisted of the alcohol 3rsquo-(trifluoromethyl)phenyl ethanol Similar treatment of

propiophenone gave trans-β-methylstyrene in 96 yield with trace amounts of the cis isomer

(Table 34 entry 3) In a similar timeframe the deoxygenation of isobutyrophenone was

performed giving 75 of the hydrocarbon 2-methyl-1-phenyl-propene while 10 of the mixture

consisted of the alcohol 1-phenyl-1-propanol (Table 34 entry 4) In this case the comparatively

slower deoxygenation rate is presumably due to increased steric hindrance about the carbonyl

functionality Indeed these effects are more pronounced with 222-trimethylacetophenone as no

reaction was observed Finally the bicyclic ketone 1-tetralone gave 12-dihydronaphthalene in

88 yield (Scheme 312 a)

Table 34 ndash Deoxygenation of aryl alkyl ketones

Entry R R1 R2 Isolated yield

1 H Me CH2 92

2 CF3 Me CH2 95

3 H Et CHCH3 trans 96

cis 4

4 H iPr C(Me)2 75

109

In light of the established tandem hydrogenation and deoxygenation protocol under these

conditions benzophenone is deoxygenated to give diphenylmethane in 81 yield (Table 35

entry 1) Similarly the diaryl ketone derivatives with substituents including CH3O Br tBu and

CH3 groups were reduced affording the corresponding diarylmethane products in yields ranging

from 67 - 99 (Table 35 entries 2 - 5) In the case of p-CF3 substituted benzophenone the

reaction gave 10 of the deoxygenation and 50 of the alcohol products (Table 35 entry 6)

Analogous treatment of 2-methylbenzophenone resulted in only 20 conversion to the aromatic

hydrocarbon (Table 35 entry 7) This example including the result for 2rsquo-

(trifluoromethyl)acetophenone (25 yield) (Table 33 entry 13) certainly infer that increased

steric hindrance about the carbonyl group has a negative impact on reactivity

Finally the tricyclic ketone dibenzosuberone afforded the reduced aryl alkane

dibenzocycloheptene in 73 yield (Scheme 312 b) It is noteworthy that Repo et al have

previously reported B(C6F5)3 mediated reductive deoxygenation of acetophenone in CD2Cl2

however in their case concurrent hydration of the borane affords (C6F5)2BOH and C6F5H178 In

the present system MS preclude this degradation pathway allowing deoxygenation to proceed

catalytically

Table 35 ndash Deoxygenation of diaryl ketones

Entry R R1 Isolated yield

1 H Ph 81

2 CH3O Ph 85

3 Br Ph 67

4 tBu Ph gt99

5 CH3 p-CH3C6H4 75

6 CF3 Ph 10

7 H o-CH3C6H4 20

110

Scheme 312 ndash Hydrogenation and deoxygenation of 1-tetralone (a) and dibenzosuberone (b)

3210 Proposed mechanism for catalytic carbonyl hydrogenation and reductive deoxygenation

The mechanism of these ketone and aldehyde reductions is thought to be analogous to the FLP

reductions described earlier in ethereal solvents In the present case the FLP initiating

heterolytic H2 activation is believed to be the Lewis basic oxygen atoms on the surface of the α-

CD or MS and the Lewis acid B(C6F5)3 (Scheme 313) although H2 activation by ketone

B(C6F5)3 cannot be dismissed Proceeding from the former activation method similar to the case

in ethereal solvents the protonated surface hydrogen bonds to the carbonyl fragment polarizing

the bond for hydride transfer from the [HB(C6F5)3]- anion The generated alkoxide anion is then

sufficiently basic to accept proton from the surface thus regenerating the heterogeneous Lewis

base This H2 activation is in agreement with HD equilibration experiments presented for α-CD

and MS

The ease of deoxygenating the ketones Ph2C=O gt PhCH3C=O gave insight to postulate the

reductive deoxygenation mechanism Heterolytic H2 activation occurs between the MS and

B(C6F5)3 although activation between ketoneB(C6F5)3 and alcoholB(C6F5)3 cannot be

dismissed ultimately resulting in protonated alcohol which is hydrogen-bonded to ketone

(Scheme 313) At this stage it appears that C-O bond cleavage with hydride delivery and loss

of H2O affords the aromatic alkene or alkane products Evidence of the alcohol-H-ketone

intermediate proposed in the mechanism is investigated in the following section

111


deoxygenation of aryl ketones

Experimental results have demonstrated electronic effects directly impact the deoxygenation

mechanism It appears that C-O bond cleavage and loss of H2O is governed by stability of an

alcohol carbocation intermediate Aryl alcohols readily stabilize such an intermediate through

delocalization by the neighbouring π-system while this effect is clearly absent with dialkyl and

primary alcohols Moreover electron withdrawing groups prevent formation of the carbocation

as demonstrated by the reduction results of 222-trifluoroacetophenone and 4-

(methylsulfonyl)acetophenone These compounds exclusively gave the corresponding alcohol

products (Table 33 entries 12 and 14)

32101 Verifying the reductive deoxygenation mechanism

To validate the proposed reductive deoxygenation mechanism treatment of diphenylmethanol

with 5 mol B(C6F5)3 and MS was carried out at 70 degC under H2 (60 atm) (Figure 37)

Surprisingly the reaction only gave 10 mol of diphenylmethane and complete degradation of

B(C6F5)3 Modification of the study to include 5 10 and 50 mol of benzophenone gradually

increased consumption of diphenylmethanol indicating participation of ketone in the

deoxygenation process (Figure 37) Such a mechanism accounts for necessity of a strong

112

Broslashnsted acid to initiate the deoxygenation process by protonating the hydroxyl group



(749 and 722 ppm) is gradually increased

The conversion of carbonyl substrates to hydrocarbons is an important and rather broad area of

research in modern organic chemistry with extensive contribution to the production of fuels

Replacement of an oxo group by two hydrogen atoms is generally carried out through

hydrogenolysis although hydrogenation methods are also well studied Prominent procedures for

this transformation include the Clemmensen reduction294-295 Wolff-Kishner reduction296 and

stoichiometric methods involving LiAlH4-AlCl3 NaBH4-CF3CO2H297 Et3SiH-BF3 or

CF3CO2H298-299 and HI-Phosphorus combinations300-301 in addition to metal-catalyzed

approaches62

From the perspective of FLP systems reductive deoxygenation of carbonyl groups has been

previously achieved using silanes boranes or ammonia borane165 as sacrificial reducing agents

0 mol

5 mol

10 mol

50 mol

Diphenylmethanol (CH) Diphenylmethane (CH2)

113

The Piers group showed the B(C6F5)3 catalyzed deoxygenative hydrosilylation of CO2 to CH4

using TMP B(C6F5)3 and excess Et3SiH169 Such transformations have also been reported using

N-heterocyclic carbenes and hydrosilanes302 The Fontaine group among others111 163 have

shown the hydroboration of CO2 to methanol using FLPs167-168 Significantly more challenging is

H2 as the reducing reagent In a unique example Ashley and OrsquoHare reported the reduction of

CO2 by H2 using a stoichiometric combination of B(C6F5)3 and TMP at 160 degC to give methanol

in 17 - 25 yield259

3211 Other heterogeneous Lewis bases and attempting the hydrogenation of olefins

In the experiments presented 4 Aring pellet MS purchased from Sigma Aldrich were used in

combination with B(C6F5)3 To explore the efficacy of other materials the same hydrogenation

protocol was applied in the reduction of 4-heptanone to give 4-heptanol in the following yields 5

Aring MS pellets (gt99) 4 Aring MS powder (69) 3 Aring MS pellets (68) acidic alumina (30)

silicic acid (15) while no reactivity was observed in the case of silica gel sodium aluminate

neutral and basic alumina

The hydrogenation protocol using 4 Aring MS was also attempted in the reduction of olefins

including 1-hexene cyclohexene 11-diphenylethylene and αp-dimethylstyrene however no

reactivity was observed in either case

33 Conclusions

The following chapter provides an account on the discovery of a metal-free route for the

hydrogenation of ketone and aldehyde substrates to form alcohol products The FLP catalyst is

derived from ether and B(C6F5)3 in which the protonated ether participates in hydrogen-bonding

interactions with the substrate affording an efficient catalyst to mediate the transformations

Moreover B(C6F5)3-assisted ketone hydrogenations using a two component catalyst system

derived from B(C6F5)3 and [NEt4][HB(C6F5)3] has also proven viable

Simultaneous with communicating this finding Ashley et al reported an analogous

hydrogenation catalyst derived from 14-dioxaneB(C6F5)3 that is effective for the hydrogenation

of ketones and aldehydes at 4 atm of H2 and temperatures ranging between 80 and 100 degC260

114

Also an air stable catalyst derived from THFB(C6Cl5)(C6F5)2 was shown to be particularly

effective for the hydrogenation of weakly Lewis basic substrates286

Continuing to explore modifications and applications of this new metal-free carbonyl reduction

protocol catalytic reductions were achieved in toluene using B(C6F5)3 and a heterogeneous

Lewis base including CDs (poly)saccharides or MS This combination of soluble borane and

insoluble materials provided a facile route to alcohol products In the case of aryl ketones and

MS further reactivity of the alcohol resulted in deoxygenation of the carbonyl group affording

either the aromatic alkane or alkene products


341 General Considerations



freezer) Pentane tetrahydrofuran toluene (Sigma Aldrich) were dried employing a Grubbs-type

column system (Innovative Technology) degassed and stored over molecular sieves (4 Aring) in the

glovebox Bromobenzene (-H5 and -D5) were purchased from Sigma Aldrich and dried over

CaH2 for several days and vacuum distilled onto 4 Aring molecular sieves prior to use

Dichloromethane-d2 benzene-d6 and chloroform-d were purchased from Sigma Aldrich

Toluene-d8 was purchased from Sigma Aldrich and distilled over sodiumbenzophenone prior to

use Molecular sieves (4 Aring) were purchased from Sigma Aldrich and dried at 120 ordmC under

vacuum for 12 h prior to use B(C6F5)3 was purchased from Boulder Scientific and sublimed at

80 degC under high vacuum before use

Tetrahydropyran 14-dioxane and hexamethyldisiloxane were purchased from Sigma Aldrich

and distilled over sodiumbenzophenone prior to use Diphenyl ether (ReagentPlusreg ge99) was

purchased from Sigma Aldrich and distilled under high vacuum at 80 degC over anhydrous

calcium chloride prior to use Diethyl ether (anhydrous 99) was purchased from Caledon

Laboratories Ltd and passed through a Grubbs-type column system manufactured by Innovative

Technology and stored over 4 Aring molecular sieves overnight prior to use Diisopropyl ether

(anhydrous 99 contains either BHT or hydroquinone as stabilizer) was purchased from Sigma

Aldrich and used without purification Cyclodextrins (α β and γ) maltitol dextrin from maize

starch and molecular sieves (pellets 32 mm diameter 4 Aring) were purchased from Sigma Aldrich

115

dried under vacuum at 120 degC for 12 h prior to use Deuterium hydride (extent of labeling 96

mol HD 98 atom D) was purchased from Sigma Aldrich Potassium

tetrakis(pentafluorophenyl)borate was purchased from Alfa Aesar Sodium triethylborohydride

(1M in toluene) was purchased from Sigma Aldrich Borenium cation-based FLP catalysts were

prepared by Dr Jeffrey M Farrell and Mr Roy Posaratnanathan following the literature

protocol105

All ketones and alcohols were purchased from Alfa Aesar Sigma Aldrich or TCI The liquids

were stored over 4 Aring molecular sieves and used without purification The solids were placed

under dynamic vacuum overnight prior to use H2 (grade 50) was purchased from Linde and

dried through a Nanochem Weldassure purifier column prior to use For the high pressure Parr

reactor the H2 was dried through a Matheson TRI-GAS purifier (type 452)


400 MHz Agilent DD2 600 MHz or an Agilent DD2 500 MHz spectrometer Spectra were

referenced to residual solvent of C6D6 (1H = 716 ppm 13C = 1284 ppm) C6D5Br (1H = 728

ppm for meta proton 13C = 1224 ppm for ipso carbon) CD2Cl2 (1H = 532 ppm 13C = 5384

ppm) d8-tol (1H = 208 ppm for CH3 13C = 13748 ppm for ipso carbon) CDCl3 (1H = 726 ppm 13C = 7716 ppm) or externally (11B (Et2O)BF3 19F CFCl3) Chemical Shifts (δ) are reported in

ppm and the absolute values of the coupling constants (J) are in Hz NMR assignments are

supported by additional 2D and DEPT-135 experiments

High Resolution Mass Spectroscopy (HRMS) was obtained using JMS T100-LC AccuTOF

DART with ion source Direct Analysis in Real Time (DART) Ionsense Inc Saugus MA GC-

MS spectra were obtained on an Agilent Technologies 5975C VL MSD with Triple-Axis

Detector and 7890A GC System Column Agilent 19091S-433 (30 m times 250 μm times 025 μm)

Oven 40 degC for first 10 min 10 degCmin to 300 degC for 10 min Injection volume 1 μL The pro-

chiral samples were analyzed using a Perkin Elmer Autosystem CL chromatograph with a chiral

column (CP Chirasil-Dex CB 25 m times 25 mm)

Jutzi acid [(Et2O)2H][B(C6F5)4]287 and silylation of α-CD with tert-butyldimethylsilyl chloride292

were prepared according to literature procedures

116

Solid materials were purchased from commercial sources 5 Aring molecular sieves (pellets 32 mm

Aldrich) 4 Aring molecular sieves (powder Aldrich) 3 Aring molecular sieves (rod 116 inches

Aldrich) aluminum oxide (weakly acidic 150 mesh 58 Aring SA = 155 m2g Aldrich) sodium

metasilicate (18 mesh granular Alfa Aesar) silicic acid (80 mesh powder Aldrich) silica gel

(200-425 mesh 60 Aring high purity grade Silicycle) sodium aluminate (powder Aldrich)

aluminum oxide (basic 150 mesh 58 Aring SA = 155 m2g Aldrich) aluminum oxide (neutral

150 mesh 58 Aring SA = 155 m2g Aldrich)

342 Synthesis of Compounds

3421 Procedures for reactions in ethereal solvents

4-Heptanol-B(C6F5)3 adduct experiment In the glove box an NMR tube was charged with a

d8-toluene (04 mL) solution of B(C6F5)3 (122 mg 240 μmol 100 mol) and 4-heptanol (279

mg 0240 mmol) The NMR tube was sealed with Parafilm and placed in an 80 degC oil bath for

12 h 19F and 11B NMR spectra were obtained No evidence for the formation of C6F5H was

observed

19F NMR (377 MHz CD2Cl2) δ -1326 (m 2F o-C6F5) -1552 (t 3JF-F = 22 Hz 1F p-C6F5) -

1628 (m 2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ 197 (br s 4-heptanol-B(C6F5)3)

Synthesis of (CH3CH2CH2)2CHOB(C6F5)2from the reaction of 4-heptanone and HB(C6F5)2

In the glove box an NMR tube was charged with a d8-toluene (04 mL) solution of HB(C6F5)2

(834 mg 0240 mmol) and 4-heptanone (274 mg 0240 mmol) A second NMR tube was

charged with a d8-toluene (04 mL) solution of HB(C6F5)2 (83 mg 24 μmol 10 mol) and 4-

heptanone (274 mg 0240 mmol) After 10 min at RT the samples were analyzed by 1H 19F

and 11B NMR spectroscopy

1H NMR (400 MHz d8-tol) δ 405 (tt 3JH-H = 76 38 Hz 1H CH) 168-151 (m 2H CH2)

150 - 134 (m 4H CH2) 133 - 115 (m 2H CH2) 086 (t 3JH-H = 76 Hz 6H CH3) 19F NMR


2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ 394 (br s (CH3CH2CH2)2CHOB(C6F5)2)

High temperature NMR study for the reduction of 4-heptanone using 5 equivalent of Et2O

(J-Young Experiment) In the glove box a 1 dram vial was charged with a d8-toluene (03 mL)

117

solution of B(C6F5)3 (61 mg 12 μmol 50 mol) 4-heptanone (274 mg 0240 mmol) and Et2O

(890 mg 125 μL 120 mmol) The reaction mixture was transferred into an oven-dried Teflon

screw cap J-Young tube The reaction tube was degassed once through a freeze-pump-thaw cycle

on the vacuumH2 line and filled with H2 (4 atm) at -196 degC The reaction was monitored by high

temperature 1H NMR spectroscopy at 70 degC with 15 minute acquisitions (Figure 31)

General procedure for reactions in ethereal solvents (Table 31) The following procedure is

common to the ketone hydrogenation reactions in Et2O iPr2O Ph2O and TMS2O In the glove

box a 2 dram vial equipped with a stir bar was charged with the respective ketone or aldehyde

(048 mmol) and B(C6F5)3 (122 mg 240 μmol 500 mol) To each vial the appropriate ether

(96 mmol 20 eq) was added using a syringe Et2O (10 mL) iPr2O (13 mL) Ph2O (15 mL) and

TMS2O (20 mL) The vial was loosely capped and loaded in a Parr pressure reactor sealed

carefully and removed from the glove box to be pressurized with hydrogen gas

The hydrogen gas line was thoroughly purged and the reactor was attached to it and purged 10

times at 15 atm of hydrogen gas The reactor was then placed in an oil bath set at 70 degC 540 rpm

and sealed at 60 atm of hydrogen gas for 12 h After the indicated reaction time the reactor was

vented and the vials were exposed to the atmosphere In the case of Et2O and iPr2O the entire

reaction mixture was transferred to a round bottom flask and all the volatiles were collected by

vacuum distillation while cooling the collected distillate with liquid nitrogen The solvent was

then removed by applying a gentle stream of N2 gas The alcohol yields were recorded and the

products were characterized by NMR spectroscopy and GC-MS

General procedure for 100 gram reaction of 4-heptanone in Et2O In the glove box 4-

heptanone (100 g 876 mmol) was weighed into a 125 mL screw-capped bottle Subsequently

B(C6F5)3 (0224 g 0430 mmol 500 mol) dissolved in Et2O (143 mg 200 mL 0190 mol)

was added to the bottle The reaction vessel was equipped with a stir bar loosely capped and

placed inside a Parr pressure reactor The reactor was sealed removed from the glove box and

attached to a purged hydrogen gas line The reactor was purged ten times at 15 atm with

hydrogen gas The reactor was then pressurized with 60 atm hydrogen gas and placed in an oil

bath for 12 h at 70 degC and 540 rpm After the indicated reaction time the reactor was slowly

vented and all the volatiles were collected by vacuum distillation while cooling the collected

distillate with liquid nitrogen The solvent was removed by applying a gentle stream of N2 gas

118

By 1H NMR spectroscopy the product displayed complete conversion to 4-heptanol and was

isolated in 87 yield

Dependence of Et2O equivalents on the reduction of 4-heptanone (Figure 32) In the glove

box a stock solution consisting of 4-heptanone (192 mg 235 μL 167 mmol) and B(C6F5)3 (427

mg 800 μmol 500 mol) in toluene (35 mL) was prepared in a 2 dram vial The solution was

distributed evenly between seven 2-dram vials (053 mLvial) and each vial was equipped with a

stir bar To each vial the appropriate volume of Et2O was added using a (micro)syringe

Et2O volume 12 μL (005 eq) 25 μL (01 eq) 125 μL (05 eq) 252 μL (10 eq) 504 μL (20

eq) 756 μL (30 eq) 101 μL (40 eq) 126 μL (50 eq) 151 μL (60 eq) 176 μL (70 eq) 202 μL

(80 eq)

The vial was loosely capped and loaded in a Parr pressure reactor sealed carefully and removed

from the glove box to be pressurized with hydrogen gas The hydrogen gas line was thoroughly

purged and the reactor was attached to it and purged 10 times at 15 atm of hydrogen gas The

reactor was then placed in an oil bath set at 70 degC 540 rpm and sealed at 60 atm of hydrogen gas

for 12 h After the indicated reaction time the reactor was vented and the reactions were analyzed

by 1H NMR spectroscopy Percent conversion to 4-heptanol was obtained by integration relative

to the remaining starting material 4-heptanone

Synthesis of [iPr2O-HmiddotmiddotmiddotO=C(CH2Ph)CH2CH3][B(C6F5)4] (31) In the glove box to a 2 dram

vial was added [(Et2O)2H][B(C6F5)4] (130 mg 0157 mmol) 4-phenyl-2-butanone (349 mg

0235 mmol) iPr2O (1284 mg 126 mmol) and toluene (05 mL) The solution was transferred

into a Teflon-sealed Schlenk bomb (25 mL) equipped with a stir bar and heated at 70 degC for 2 h

The solvent was removed under vacuum and pentane (5 mL) was added to result in immediate

precipitation of a white solid that was washed again with pentane (3 mL) and dried under

vacuum (127 g 136 mmol 87) Crystals suitable for X-ray crystallographic studies were

obtained from a layered bromobenzenepentane solution at RT

1H NMR (400 MHz CD2Cl2) δ 1152 (br s 1H iPr2O-HmiddotmiddotmiddotO=C) 741 (m 3H m p-Ph) 718

(m 2H o-Ph) 468 (m 3JH-H = 68 Hz 2H iPr) 403 (s 2H PhCH2) 281 (q 3JH-H = 71 Hz

2H CH2CH3) 146 (d 3JH-H = 68 Hz 12H iPr) 117 (t 3JH-H = 71 Hz 3H CH2CH3) 19F NMR


119

2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ -168 (s B(C6F5)4) 13C1H NMR (125 MHz

CD2Cl2) δ 1480 (dm 1JC-F = 238 Hz CF) 1379 (dm 1JC-F = 243 Hz CF) 1362 (dm 1JC-F =

246 Hz CF5) 1319 (ipso-Ph) 1301 (m-Ph) 1298 (o-Ph) 1288 (p-Ph) 1240 (ipso-C6F5) 828

(iPr) 498 (CH2Ph) 373 (CH2CH3) 197 (iPr) 799 (CH2CH3) (C=O was not observed)

HRMS (DART-TOF+) mass [M]+ calcd for [C16H27O2]+ 25120110 Da Found 25120127 Da

mass [M]- calcd for [C24BF20]- 67897736 Da Found 67897745 Da

3422 Procedures for reactions using B(C6F5)3 and [NEt4][HB(C6F5)3]

Synthesis of [NEt4][HB(C6F5)3] Part 1 In the glove box a 4 dram vial equipped with a stir bar

was charged with a solution of B(C6F5)3 (200 mg 0391 mmol) in toluene (10 mL) To the vial

sodium triethylborohydride (1M in toluene) (036 mL 036 mmol) was added drop wise over 15

min The reaction was allowed to mix overnight prior to removing the volatiles under vacuum

The crude mixture was washed with pentane (5 mL) to give the product Na HB(C6F5)3 as a white

solid (187 mg 0348 mmol 89)

Part 2 Na HB(C6F5)3 (187 mg 0348 mmol) was subsequently added to CH2Cl2 (10 mL) and


reaction was allowed to mix at RT overnight and filtered through Celite The filtrate was


0320 mmol 92)

1H NMR (400 MHz d8-tol) δ 415 (br q 1JB-H = 91 Hz 1H BH) 211 (q 3JH-H = 74 Hz 8H

Et) 046 (tm 3JH-H = 74 Hz 12H Et) 19F NMR (377 MHz CD2Cl2) δ -13361 (m 2F o-C6F5)

-1635 (t 3JF-F = 20 Hz 1F p-C6F5) -1663 (m 2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ -

247 (d 1JB-H = 91 Hz BH)

General procedure for reactions in toluene using B(C6F5)3 and [NEt4][HB(C6F5)3] (Table

32) In the glovebox a 2 dram vial equipped with a stir bar was charged with the respective

ketone (048 mmol) B(C6F5)3 (122 mg 240 μmol 500 mol) and [NEt4][HB(C6F5)3] (154

mg 240 μmol 500 mol) in toluene (10 mL) The vial was loosely capped and loaded in a

Parr pressure reactor sealed carefully and removed from the glovebox to be pressurized with

hydrogen gas The hydrogen gas line was thoroughly purged and the reactor was attached to it

and purged 10 times at 15 atm of hydrogen gas The reactor was then placed in an oil bath set at

80 degC 540 rpm and sealed at 60 atm of hydrogen gas for 12 h After the indicated reaction time

120

the reactor was vented and the reactions were analyzed by 1H NMR spectroscopy Percent

conversion to the alcohol product was obtained by integration relative to the remaining starting

material ketone

3423 Procedures for reactions using heterogeneous Lewis bases

General procedure for reactions in toluene using heterogeneous Lewis bases (Table 33) In

the glovebox a 2 dram vial equipped with a stir bar was charged with the respective ketone (048

mmol) B(C6F5)3 (122 mg 240 μmol 500 mol) and the respective heterogeneous Lewis base

in toluene (10 mL) The vial was loosely capped and loaded in a Parr pressure reactor sealed

carefully and removed from the glovebox to be pressurized with hydrogen gas The hydrogen gas

line was thoroughly purged and the reactor was attached to it and purged 10 times at 15 atm of

hydrogen gas The reactor was then placed in an oil bath set at 60 degC 430 rpm and sealed at 60

atm of hydrogen gas for 12 h Products were isolated by appropriate work-up methods The

alcohol yields were recorded and the products were characterized by NMR spectroscopy and

GC-MS

Heterogeneous Lewis bases α-CD (467 mg 0480 mmol) β-CD (467 mg 0410 mmol) γ-CD

(467 mg 0360 mmol) maltitol (168 mg 0480 mmol) dextrin (350 mg) MS (100 mg)

General procedure 100 g scale reduction of 4-heptanone using MS In the glovebox 4-


B(C6F5)3 (0224 g 0430 mmol) dissolved in toluene (7 mL ) was added to the bottle in addition

to 302 g of 4 Aring MS The reaction vessel was equipped with a stir bar loosely capped and

placed inside a Parr pressure reactor The reactor was sealed removed from the glovebox and



bath for 12 h at 70 degC and 430 rpm The reactor was slowly vented and an aliquot was taken in

d8-toluene and complete conversion of 4-heptanone to 4-heptanol was determined by 1H NMR

spectroscopy The reaction mixture was filtered through a frit and washed with dichloromethane

(2 times 10 mL) The collected molecular sieves were extracted with dichloromethane (3 times 10 mL)

and water (20 mL) The organic fraction was dried over magnesium sulfate and combined with

the toluene fraction The two solvents dichloromethane and toluene were removed by fractional

121

distillation 4-Heptanol was then collected under vacuum in a liquid nitrogen cooled Schlenk

flask The product was collected as a colourless liquid (0885 g 762 mmol 87)

3424 Procedures for reductive deoxygenation reactions

General procedure for deoxygenation reactions using molecular sieves (Table 34 and Table

35) This method follows the same procedure for reactions in Table 33 using 4 Aring MS The

reactor was placed in an oil bath set at 70 degC 340 rpm and sealed at 60 atm of hydrogen gas for

12 h Products were isolated by appropriate work-up methods The aromatic hydrocarbon yields

were recorded and the products were characterized by NMR spectroscopy and GC-MS

Verifying the deoxygenation mechanism In the glovebox four separate 2-dram vials were

loaded with diphenylmethanol (442 mg 0240 mmol) and B(C6F5)3 (61 mg 12 μmol 50

mol) To each vial the indicated equivalents of benzophenone were added (21 mg 12 μmol

50 mol 44 mg 24 μmol 10 mol 218 mg 0120 mmol 50 mol) followed by the

addition of d8-toluene (05 mL) and 4 Aring MS (100 mg) The reaction vials were equipped with a

stir bar loosely capped and placed inside a Parr pressure reactor The reactor was sealed

removed from the glovebox and attached to a purged hydrogen gas line The reactor was purged

ten times at 15 atm with hydrogen gas The reactor was then pressurized with 60 atm hydrogen

gas and placed in an oil bath for 12 h at 70 degC and 340 rpm After the indicated reaction time the

reactor was slowly vented and an aliquot was taken in d8-toluene and conversion of the

diphenylmethanol to diphenylmethane was determined by 1H NMR spectroscopy

3425 Spectroscopic data of products in Table 31

All GC-MS results have been compared to starting materials and commercially purchased

alcohol products

4-Heptanol (Entry 1) 1H NMR (500 MHz C6D5Br) δ 472 (br s 1H OH) 341 (tt 3JH-H = 70

Hz 46 Hz 1H CH) 124 (m 4H CHCH2) 114 (m 4H CH2CH3) 082 (t 3JH-H = 67 Hz 6H

CH3) 13C1H NMR (125 MHz C6D5Br) δ 721 (CH) 390 (CHCH2) 184 (CH2CH3) 135

(CH3) GC-MS 11928 min mz = 981 [M-H2O] 730 [M-C3H7] 550 [M-C3H9O]

3-Methylbutan-2-ol (Entry 2) 1H NMR (500 MHz C6D5Br) δ 339 (qd 3JH-H = 63 Hz 53

Hz 1H CHOH) 145 (m 1H iPr) 115 (br s 1H OH) 100 (d 3JH-H = 63 Hz 3H CH3) 083

122

(d 3JH-H = 68 Hz 3H iPr) 080 (d 3JH-H = 68 Hz 3H iPr) 13C1H NMR (125 MHz

C6D5Br) δ 719 (CHOH) 347 (iPr) 200 (CH3) 180 (iPr) 175 (iPr) GC-MS 3150 min mz

= 731 [M-CH3] 551 [M-CH5O]

44-Dimethylpentan-2-ol (Entry 3) 1H NMR (500 MHz C6D5Br) δ 380 (m 1H CH) 368

(br s 1H OH) 127 (dd 2JH-H = 143 Hz 3JH-H = 79 Hz 1H CH2) 116 (dd 2JH-H = 143 Hz 3JH-H = 33 Hz 1H CH2) 105 (d 3JH-H = 62 Hz 3H CH3) 087 (s 9H tBu) 13C1H NMR

(125 MHz C6D5Br) δ 660 (CH) 526 (CH2) 300 (tBu) 299 (tBu) 258 (CH3) GC-MS 6776

min mz = 1011 [M-CH3] 831 [M-CH5O] 701 [M-C2H6O] 571 [M-C3H7O]

Heptan-2-ol (Entry 4) 1H NMR (500 MHz d8-tol) δ 424 (br s 1H OH)

348 (m 3JH-H = 60 Hz 1H H2) 126 (m 2H H6) 123 (m 2H H3 H4)

118 - 114 (m 4H H3 H4 H5) 097 (d 3JH-H = 60 Hz 3H H1) 090 (t 3JH-H = 71 Hz 3H

H7) 13C1H NMR (125 MHz d8-tol) δ 684 (C2) 392 (C3) 319 (C5) 255 (C4) 228 (C1

C6) 139 (C7) GC-MS 12395 min mz = 1011 [M-CH3] 981 [M-H2O] 871 [M-C2H5]

1-Chloropropan-2-ol (Entry 5) 1H NMR (500 MHz C6D5Br) δ 432 (br s 1H OH) 362 (m 3JH-H = 68 Hz 1H CH) 316 (dd 2JH-H = 113 Hz 3JH-H = 35 Hz 1H CH2Cl) 304 (dd 2JH-H =

113 Hz 3JH-H = 68 Hz 1H CH2Cl) 090 (d 3JH-H = 61 Hz 3H CH3) 13C1H NMR (125

MHz C6D5Br) δ 692 (CH) 502 (CH2Cl) 222 (CH3) GC-MS 3383 min mz = 810 [(M+2)-

CH3] 790 [M-CH3]

1-Cyclohexylethan-1-ol (Entry 6) 1H NMR (400 MHz d8-tol) δ 330 (quint 3JH-H = 74 Hz

1H CH) 182 - 147 (m 5H Cy) 131 (br s 1H OH) 125 - 102 (m 4H Cy) 098 (d 3JH-H =

74 Hz 3H CH3) 087 (m 2H Cy) 13C1H NMR (125 MHz d8-tol) δ 721 (CHOH) 452

(CyCH) 287 (Cy) 268 (Cy) 267 (Cy) 205 (CH3) GC-MS 14245 min mz = 1131 [M-CH3]

1101 [M- H2O] 831 [M-C2H5O]

2-Methylpentan-3-ol (Entry 7) 1H NMR (500 MHz C6D5Br) δ 410 (br s 1H OH) 308

(ddd 3JH-H = 88 Hz 52 Hz 38 Hz 1H CHOH) 146 (m 3JH-H = 68 Hz 52 Hz 1H iPr) 133

(dqd 2JH-H = 140 Hz 3JH-H = 75 Hz 39 Hz 1H CH2) 120 (ddq 2JH-H = 140 Hz 3JH-H = 86

Hz 75 Hz 1H CH2) 081 (t 3JH-H = 75 Hz 3H CH3) 077 (d 3JH-H = 68 Hz 3H iPr) 076

(d 3JH-H = 68 Hz 3H iPr) 13C1H NMR (125 MHz C6D5Br) δ 783 (CHOH) 326 (iPr) 264

123

(CH2) 184 (iPr) 167 (iPr) 994 (CH3) GC-MS 5663 min mz = 841 [M-H2O] 731 [M-

C2H5] 591 [M-C3H7]

Heptan-3-ol (Entry 8) 1H NMR (500 MHz C6D5Br) δ 450 (br s 1H

OH) 335 (tt 3JH-H = 73 Hz 47 Hz 1H H3) 136-130 (m 2H H2) 128-

121 (m 5H H4 H5 H6) 115 (m 1H H5) 084 (t 3JH-H = 57 Hz 3H H7) 083 (t 3JH-H = 57

Hz 3H H1) 13C1H NMR (125 MHz C6D5Br) δ 732 (C3) 362 (C4) 295 (C2) 275 (C5)

226 (C6) 138 (C7) 961 (C1) GC-MS 12171 min mz = 981 [M-H2O] 831 [M-CH5O]

691 [M-C2H7O] 590 [M-C4H9]

5-Methylhexan-3-ol (Entry 9) 1H NMR (400 MHz d8-tol) δ (tt 3JH-H = 87 51 Hz 1H

CHOH) 201 (m 2H CH2CH3) 148 (m 3JH-H = 69 51 Hz 1H iPr) 130 (m 1H CH2iPr)

126 (m 1H CH2iPr) 089 (d 3JH-H = 69 Hz 6H iPr) 085 (t 3JH-H = 72 Hz 3H CH3)

13C1H NMR (101 MHz d8-tol) δ 785 (CHOH) 337 (iPr CH2CH3) 273 (CH2iPr) 188

(iPr) 171 (iPr) 104 (CH3) GC-MS 9458 min mz = 871 [M-Et] 691 [M-C2H7O] 591 [M-

CH2iPr]

1-Phenylethan-1-ol (Entry 10) 1H NMR (400 MHz C6D6) δ 702 (m 5H Ph) 428 (q 3JH-H =

65 Hz 1H CH) 342 (br s 1H OH) 102 (d 3JH-H = 65 Hz 3H CH3) 13C1H NMR (125

MHz CDCl3) δ 1460 (ipso-Ph) 1286 (m-Ph) 1283 (p-Ph) 1254 (o-Ph) 703 (CH) 252

(CH3) GC-MS 17207 min mz = 1221 [M] 1071 [M-CH3] 1040 [M-H2O] 910 [M-CH3O]

770 [M-C2H5O]

1-Phenylbutan-2-ol (Entry 11) 1H NMR (500 MHz CD2Cl2) δ 755 (m 1H OH) 733 (tm 3JH-H = 76 Hz 2H m-Ph) 729 (dm 3JH-H = 76 Hz 2H o-Ph) 725 (tm 3JH-H = 76 Hz 1H p-

Ph) 376 (dq 3JH-H = 81 Hz 42 Hz 1H CH) 286 (dd 2JH-H = 136 Hz 3JH-H = 43 Hz 1H

CH2Ph) 266 (dd 2JH-H = 136 Hz 3JH-H = 81 Hz 1H CH2Ph) 152 (q 3JH-H = 77 Hz 2H

CH2CH3) 102 (t 3JH-H = 77 Hz 3H CH3) 13C1H NMR (125 MHz CD2Cl2) δ 1391 (ipso-

Ph) 1295 (m-Ph) 1284 (o-Ph) 1263 (p-Ph) 739 (CH) 437 (CH2Ph) 303 (CH2CH3) 960

(CH3) GC-MS 20079 min mz = 1321 [M-H2O] 1030 [M-C2H7O] 911 [M-C3H7O]

591[M-C7H7]

4-Phenylbutan-2-ol (Entry 12) 1H NMR (500 MHz C6D5Br) δ 720 (t 3JH-H = 74 Hz 2H m-

Ph) 710 (t 3JH-H = 74 Hz 1H p-Ph) 706 (d 3JH-H = 74 Hz 2H o-Ph) 373 (br s 1H OH)

124

362 (dqd 3JH-H = 74 Hz 62 Hz 50 Hz 1H CH) 255 (m 2H PhCH2) 160 (m 2H CH2CH)

103 (d 3JH-H = 62 Hz 3H CH3) 13C1H NMR (125 MHz C6D5Br) δ 1411 (ipso-Ph) 1281

(m-Ph) 1280 (o-Ph) 1255 (p-Ph) 673 (CH) 403 (PhCH2) 317 (CH2CH) 229 (CH3) GC-

MS 20438 min mz = 1501 [M] 1321 [M-H2O] 1170 [M-CH5O] 1051 [M-C2H5O] 911

[M-C3H7O]

1-(2-Fluorophenyl)propan-2-ol (Entry 13) 1H NMR (500 MHz CD2Cl2) δ

753 (m 1H OH) 733 - 705 (m 4H C6H4F) 406 (m 1H CH) 284 (dd 2JH-

H = 139 Hz 3JH-H = 51 Hz 1H CH2) 276 (dd 2JH-H = 139 Hz 3JH-H = 77

Hz 1H CH2) 124 (d 3JH-H = 62 Hz 3H CH3) 19F NMR (377 MHz CD2Cl2) δ -1178 (m

CF) 13C1H NMR (125 MHz CD2Cl2) δ 1611 (d 1JC-F = 240 Hz C1) 1318 (d 3JC-F = 59

Hz C3) 1285 (d 4JC-F = 88 Hz C4) 1257 (d 2JC-F = 16 Hz C2) 1240 (d 3JC-F = 37 Hz C5)

1152 (d 2JC-F = 22 Hz C6) 678 (d 4JC-F = 11 Hz CH) 388 (d 3JC-F = 14 Hz CH2) 229

(CH3) GC-MS 18697 min mz = 1360 [M-H2O] 960 [M-C3H6O]

1-(4-Fluorophenyl)propan-2-ol (Entry 14) 1H NMR (500 MHz CD2Cl2) δ 722 (m 2H o of

C6H4F) 705 (m 2H m of C6H4F) 399 (m 1H CH) 278 (dd 2JH-H = 137 Hz 3JH-H = 48 Hz

1H CH2) 269 (dd 2JH-H = 137 Hz 3JH-H = 78 Hz 1H CH2) 161 (br s 1H OH) 122 (d 3JH-H

= 62 Hz 3H CH3) 19F NMR (377 MHz CD2Cl2) δ -1177 (m p-C6H4F) 13C1H NMR (125

MHz CD2Cl2) δ 1616 (d 1JC-F = 243 Hz p of C6H4F) 1348 (d 4JC-F = 46 Hz ipso-C6H4F)

1307 (d 3JC-F = 82 Hz o of C6H4F) 1149 (d 2JC-F = 22 Hz m of C6H4F) 690 (CH) 449

(CH2) 227 (CH3) GC-MS 18697 min mz = 1361 [M-H2O] 960 [M-C3H6O]

1-(3-(Trifluoromethyl)phenyl)propan-2-ol (Entry 15) 1H NMR (500

MHz CD2Cl2) δ 751 (m 2H H1 H5) 744 (m 2H H3 H4) 408 (m 1H

CH) 283 (dd 2JH-H = 136 Hz 3JH-H = 49 Hz 1H CH2) 276 (dd 2JH-H =

136 Hz 3JH-H = 78 Hz 1H CH2) 181 (br s 1H OH) 123 (t 3JH-H = 62

Hz 3H CH3) 19F NMR (377 MHz CD2Cl2) δ -628 (CF3) 13C1H NMR (125 MHz CD2Cl2)

δ 1399 (C2) 1330 (q 4JC-F = 13 Hz C3) 1303 (q 2JC-F = 30 Hz C6) 1288 (C4) 1260 (q 3JC-F = 41 Hz C1) 1242 (q 1JC-F = 277 Hz CF3) 1230 (q 3JC-F = 41 Hz C5) 687 (CH) 447

(CH2) 228 (CH3) GC-MS 19011 min mz = 1861 [M-H2O] 1601 [M-C2H4O] 1171 [M-

CH2F3O]

125

Cyclohexanol (Entry 16) 1H NMR (400 MHz d8-tol) δ 324 (tt 3JH-H = 90 Hz 37 Hz 1H

CH) 177 (m 2H Cy) 168 (m 2H Cy) 142- 130 (m 3H Cy) 126- 115 (m 3H Cy)

13C1H NMR (101 MHz CD2Cl2) δ 706 (CH) 360 (CHCH2) 260 (Cy) 245 (Cy) GC-MS

4029 min mz = 1001 [M] 821 [M-H2O]

2-Isopropyl-5-methylcyclohexan-1-ol (Entry 17) 1H NMR (500 MHz

C6D5Br) δ 390 (q 3JH-H = 29 Hz 1H H1) 346 (br s 1H OH) 168 (ddd 2JH-H = 139 Hz 3JH-H = 36 Hz 24 Hz 1H H2) 164 (m 2H H3 H4) 153

(dm 2JH-H = 132 Hz 1H H5) 143 (dm 3JH-H = 92 Hz 67 Hz 1H H7) 118 (dm 2JH-H = 132

Hz 1H H5) 091 (m 1H H2) 087 (d 3JH-H = 67 Hz 3H H8) 083 (d 3JH-H = 67 Hz 3H

H9) 080 (d 3JH-H = 64 Hz 3H H10) 075 (m 1H H4) 070 (m 1H H6) 13C1H NMR (125

MHz C6D5Br) δ 675 (C1) 473 (C6) 421 (C2) 346 (C4) 288 (C7) 254 (C3) 238 (C5)


951 [M-C3H9O] 811 [M-C4H12O]

Cyclohexylmethanol (Entry 18) 1H NMR (500 MHz CD2Cl2) δ 556 (br s 1H OH) 404 (d 3JH-H = 75 Hz 2H CH2OH) 212-182 (m 1H CyCH2) 180 (m 1H CyCH) 163 - 117 (m 1H CyCH2) 13C1H NMR (125 MHz CD2Cl2) δ 693 (CH2OH) 374 (CyCH) 301 (CyCH2) 262

(CyCH2) 252 (CyCH2) GC-MS 5538 min mz = 1141 [M] 961 [M-H2O] 831 [M-CH3O]



alcohol products NMR and GC-MS data of products not reported in previous sections are listed

3-Methylpentan-2-ol (Entry 4) 1H NMR (400 MHz CDCl3) δ 376 (m 1H CHOH) 223 (br

s 1H OH) 175 - 142 (m 3H CH(Et) Et) 118 (d 3JH-H = 69 Hz 3H CH3CHOH) 098 (m

6H CH(Et)CH3 Et) 13C1H NMR (125 MHz CD2Cl2) δ 713 (CHOH) 406 (CH(Et)) 223

(Et) 198 (OHCHCH3) 120 (CH(Et)CH3) 111 (Et) GC-MS 10215 min mz = 871 [M-CH3]

561 [M-C2H6O] 450 [C2H5O]




126

222-Trifluoro-1-phenylethan-1-ol (Entry 12) 1H NMR (500 MHz d8-tol) δ 745 (m 2H m-

Ph) 717 (dm 3JH-H = 70 Hz 2H o-Ph) 711 (m 1H p-Ph) 432 (d 3JF-H = 77 Hz 1H CH)

306 (br s 1H OH) 19F NMR (470 MHz d8-tol) δ -783 (d 3JF-H = 77 Hz CF3) 13C1H NMR

(125 MHz d8-tol) δ 1341 (ipso-Ph) 1289 (m-Ph) 1276 (p-Ph) 1272 (q 4JC-F = 12 Hz o-Ph)

1234 (q 1JC-F = 297 Hz CF3) 726 (CH) GC-MS 6130 min mz = 1760 [M] 1701 [M-CF3]

3-Chloro-1-phenylpropan-1-ol (Entry 11) 1H NMR (600 MHz d8-tol) δ 712 (m 3H m p-

Ph) 703 (m 2H o-Ph) 399 (t 3JH-H = 78 Hz 1H CHOH) 312 (t 3JH-H = 67 Hz 2H CH2Cl)

251 (br s 1H OH) 218 (dt 3JH-H = 78 Hz 67 Hz 2H CHCH2CH2) 13C1H NMR (151

MHz d8-tol) δ 1440 (ipso-Ph) 1282 (m-Ph) 1275 (o-Ph) 1260 (p-Ph) 476 (CHOH) 432

(CH2Cl) 387 (CHCH2CH2) GC-MS 11210 min mz = 1701 [M] 1521 [M-H2O] 1070 [M-

C2H4Cl]

1-(2-(Trifluoromethyl)phenyl)ethan-1-ol (Entry 13) 1H NMR (500 MHz

d8-tol) δ 759 (d 3JH-H = 81 Hz 1H H2) 732 (d 3JH-H = 81 Hz 1H H5)

711 (t 3JH-H = 81 Hz 1H H3) 685 (t 3JH-H = 81 Hz 1H H4) 508 (qm 3JH-

H = 67 Hz 1H CHOH) 221 (br s 1H OH) 125 (d 3JH-H = 67 Hz 3H CH3)

19F NMR (470 MHz d8-tol) δ -582 (s CF3) 13C1H NMR (125 MHz d8-tol) δ 1455 (ipso-

C6H4CF3) 1315 (C3) 1314 (C1) 1294 (C4) 1264 (C2) 1244 (C5) 1240 (CF3) 653

(CHOH) 253 (CH3) (JC-F not reported) GC-MS 6453 min mz = 1901 [M] 1750 [M-CH3]

1720 [M-H2O] 1450 [M-C2H5O]

1-(4-(Methylsulfonyl)phenyl)ethan-1-ol (Entry 14) 1H NMR (500 MHz d8-tol) δ 763 (d 3JH-H = 86 Hz 2H o of C6H4SO2CH3) 705 (d 3JH-H = 86 Hz 2H m of C6H4SO2CH3) 437 (m

1H CHOH) 228 (s 3H SO2CH3) 141 (br s 1H OH) 112 (d 3JH-H = 66 Hz 3H CHCH3)

13C1H NMR (125 MHz d8-tol) δ 1522 (p of C6H4SO2CH3) 1402 (ipso-C6H4SO2CH3) 1270

(o of C6H4SO2CH3) 1257 (m of C6H4SO2CH3) 689 (CHOH) 436 (SO2CH3) 252 (CHCH3)

HRMS-DART+ mz [M+NH4]+ calcd for C9H16NO3S 21808509 Found 21808554

22-Diphenylethan-1-ol (Entry 24) 1H NMR (500 MHz d8-tol) δ 704 (m 1H p-Ph) 703 (m

2H m -Ph) 693 (d 3JH-H = 75 Hz 2H o-Ph) 405 (dd 3JH-H = 83 Hz 61 Hz 1H CH) 400

(m 2H CH2) (OH was not observed) 13C1H NMR (125 MHz d8-tol) δ 1418 (ipso-Ph)

1293 (m-Ph) 1287 (o-Ph) 1274 (p-Ph) 763 (CH2) 512 (CH) GC-MS 15178 min mz =

1811 [M-OH] 1671 [M-CH3O]

127

2-Phenylpropan-1-ol (Entry 25) 1H NMR (500 MHz d8-tol) δ 722 (d 3JH-H = 78 Hz 2H o-

Ph) 718 ndash 713 (m 3H m p-Ph) 362 (dd 2JH-H = 100 Hz 3JH-H = 62 Hz 1H CH2) 354 (dd 2JH-H = 100 Hz 3JH-H = 78 Hz 1H CH2) 342 (br s 1H OH) 288 (m 3JH-H = 69 Hz 1H CH)

121 (d 3JH-H = 69 Hz 3H CH3) 13C1H NMR (125 MHz d8-tol) δ 1459 (ipso-Ph) 1289 (p-

Ph) 1283 (m-Ph) 1274 (o-Ph) 780 (CH2) 435 (CH) 181 (CH3) GC-MS 6462 min mz =

1211 [M-CH3] 1051 [M-CH3O]

3428 Spectroscopic data of products in Table 34 and Scheme 312 (a)


alcohol products

Styrene (Entry 1)1H NMR (500 MHz d8-tol) δ 718 (d 3JH-H = 77 Hz 2H o-Ph) 708 (t 3JH-

H = 77 Hz 2H m-Ph) 706 (t 3JH-H = 77 Hz 1H p-Ph) 653 (dd 3JH-H = 176 Hz 109 Hz 1H

CH) 556 (dd 3JH-H = 176 Hz 11 Hz 1H CH2) 505 (dd 3JH-H = 109 Hz 11 Hz 1H CH2)

13C1H NMR (125 MHz d8-tol) δ 1379 (CH) 1372 (ipso-Ph) 1286 (o m-Ph) 1284 (p-Ph)

1140 (CH2) GC-MS 4038 min mz = 1041 [M] 911 [C7H7] 781 [C6H6]

1-(Trifluoromethyl)-3-vinylbenzene (Entry 2) 1H NMR (500 MHz d8-

tol) δ 744 (s 1H H1) 718 (d 3JH-H = 77 Hz 1H H5) 706 (d 3JH-H = 77

Hz 1H H3) 686 (t 3JH-H = 75 Hz 1H H4) 631 (dd 3JH-H = 173 Hz 102

Hz 1H CH=CH2) 544 (d 3JH-H = 173 Hz 1H CH=CH2) 504 (d 3JH-H = 102 Hz 1H

CH=CH2) 19F NMR (470 MHz d8-tol) δ -626 (s CF3) 13C1H NMR (125 MHz d8-tol) δ

1379 (ipso-C6H4CF3) 1354 (CH=CH2) 1309 (C2) 1284 (C5) 1245 (CF3) 1237 (C3) 1225

(C1) 1151 (CH=CH2) (JC-F not reported) GC-MS 4290 min mz = 1721 [M] 1531 [M-F]

1451 [M-C2H3] 1031 [M-CF3]

(E)-Prop-1-en-1-ylbenzene (Entry 3) 1H NMR (500 MHz d8-tol) δ 718 (d 3JH-H = 73 Hz

2H o-Ph) 712 (t 3JH-H = 73 Hz 2H m-Ph) 702 (t 3JH-H = 73 Hz 1H p-Ph) 626 (dq 3JH-H =

156 Hz 4JH-H = 18 Hz 1H PhCH=CH) 600 (dq 3JH-H = 156 Hz 66 Hz 1H PhCH=CH)

168 (dd 3JH-H = 66 Hz 4JH-H = 18 Hz 3H CH3) 13C1H NMR (125 MHz d8-tol) δ 1378

(ipso-Ph) 1314 (PhCH=CH) 1283 (m-Ph) 1265 (p-Ph) 1258 (o-Ph) 1248 (PhCH=CH)

1800 (CH3) GC-MS 5888 min mz = 1181 [M] 1171 [M-H] 1031 [M-CH3]

128

(2-Methylprop-1-en-1-yl)benzene (Entry 4) 1H NMR (500 MHz d8-tol) δ 717 (m 4H o m-

Ph) 705 (m 1H p-Ph) 624 (m 4JH-H = 15 Hz 1H CH=C(CH3)2) 180 (d 4JH-H = 15 Hz 3H

CH=C(CH3)2) 175 (d 4JH-H = 15 Hz 3H CH=C(CH3)2) 13C1H NMR (125 MHz d8-tol) δ

1386 (C(CH3)2) 1345 (ipso-Ph) 1287 (o-Ph) 1279 (m-Ph) 1257 (CH=C(CH3)2) 1256 (p-

Ph) 264 (CH3) 188 (CH3) GC-MS 5780 min mz = 1321 [M] 1171 [M-CH3]

12-Dihydronaphthalene (Scheme 312a) 1H NMR (600 MHz CD2Cl2) δ 746 - 731 (m 4H

C6H4) 678 (dm 3JH-H = 96 Hz 1H CH=CHCH2) 632 (m 1H CH=CHCH2) 308 (m 2H

CH2CH2CH) 258 (m 2H CH2CH=CH) 13C1H NMR (125 MHz CD2Cl2) δ 1358

(quaternary C for C6H4) 1344 (quaternary C for C6H4) 1288 (CH=CHCH2) 1280

(CH=CHCH2) 1277 (C6H4) 1271 (C6H4) 1266 (C6H4) 1261 (C6H4) 278 (CHCH2CH2) 236

(CH=CHCH2) GC-MS 7943 min mz = 1301 [M] 1151 [M-CH3] 1021 [M-C2H4]

3429 Spectroscopic data of products in Table 35 and Scheme 312 (b)


alcohol products

Diphenylmethane (Entry 1) 1H NMR (500 MHz d8-tol) δ 708 (t 3JH-H = 75 Hz 2H m-Ph)

701 (t 3JH-H = 75 Hz 1H p-Ph) 700 (d 3JH-H = 75 Hz 2H o-Ph) 372 (s 1H CH2) 13C1H

NMR (125 MHz d8-tol) δ 1413 (ipso-Ph) 1293 (o-Ph) 1286 (m-Ph) 1263 (p-Ph) 422

(CH2) GC-MS 11686 min mz = 1681 [M] 1671 [M-H] 911 [C7H7]

1-Benzyl-4-methoxybenzene (Entry 2) 1H NMR (500 MHz d8-tol) δ 712 (m 2H m-Ph)

711 (m 1H p-Ph) 705 (d 3JH-H = 67 Hz 2H o-Ph) 693 (d 3JH-H = 76 Hz 2H o of

C6H4OCH3) 670 (d 3JH-H = 76 Hz 2H m of C6H4OCH3) 372 (s 2H CH2) 334 (s 3H

OCH3) 13C1H NMR (125 MHz d8-tol) δ 1581 (p of C6H4OCH3) 1416 (ipso-C6H4OCH3)

1328 (ipso-Ph) 1295 (o of C6H4OCH3) 1287 (o-Ph) 1283 (m-Ph) 1278 (p-Ph) 1137 (m of

C6H4OCH3) 542 (OCH3) 410 (CH2) GC-MS 14801 min mz = 1981 [M] 1671 [M-OCH3]

1211 [M-C6H5] 911 [M-C7H7O] 771 [M-C8H9O]

1-Benzyl-4-bromobenzene (Entry 3) 1H NMR (500 MHz d8-tol) δ 719 (m 1H p-Ph) 716

(d 3JH-H = 78 Hz 2H m of C6H4Br) 710 (t 3JH-H = 77 Hz 2H m-Ph) 691 (d 3JH-H = 77 Hz

2H o-Ph) 665 (d 3JH-H = 77 Hz 2H o of C6H4Br) 355 (s 2H CH2) 13C1H NMR (125

MHz d8-tol) δ 1407 (ipso-C6H4Br) 1403 (ipso-Ph) 1317 (m of C6H4Br) 1316 (p-Ph) 1308

129

(o of C6H4Br) 1289 (o-Ph) 1285 (m-Ph) 1204 (p-C6H4Br) 414 (CH2) GC-MS 15250 min

mz = 2480 [M+2] 2460 [M] 1671 [M-Br] 911 [M-C6H4Br]

1-Benzyl-4-(tert-butyl)benzene (Entry 4) 1H NMR (500 MHz CD2Cl2) δ 774 (t 3JH-H = 86

Hz 2H m of C6H4tBu) 768 (t 3JH-H = 76 Hz 1H p-Ph) 761 (t 3JH-H = 76 Hz 2H m-Ph)

759 (d 3JH-H = 76 Hz 2H o-Ph) 755 (d 3JH-H = 86 Hz 2H o of C6H4tBu) 435 (s 2H CH2)

178 (s 9H tBu) 13C1H NMR (125 MHz CD2Cl2) δ 1493 (p of C6H4tBu) 1420 (ipso-Ph)

1387 (ipso-C6H4tBu) 1294 (m-Ph o of C6H4tBu) 1286 (p-Ph) 1263 (o-Ph) 1255 (m of

C6H4tBu) 415 (CH2) 347 (tBu) 315 (tBu) GC-MS 15429 min mz = 2242 [M] 2092 [M-

CH3) 911 [C7H7]

Di-p-tolylmethane (Entry 5) 1H NMR (500 MHz d8-tol) δ 699 (d 3JH-H = 78 Hz 2H o of

C6H4CH3) 694 (d 3JH-H = 78 Hz 2H m of C6H4CH3) 375 (s 1H CH2) 215 (s 3H CH3)

13C1H NMR (125 MHz d8-tol) δ 1383 (ipso-C6H4CH3) 1350 (p of C6H4CH3) 1289 (m of

C6H4CH3) 1287 (o of C6H4CH3) 408 (CH2) 206 (CH3) GC-MS 14226 min mz = 1961

[M] 1811 [M-CH3) 1661 [M-2(CH3)] 1051 [M-C7H7] 911 [M- C8H9]

1-Benzyl-4-(trifluoromethyl)benzene (Entry 6) 1H NMR (600 MHz CD2Cl2) δ 800 (d 3JH-H

= 73 Hz 2H o-Ph) 788 (d 3JH-H = 74 Hz 2H m of C6H4CF3) 778 (t 3JH-H = 73 Hz 1H p-

Ph) 767 (t 3JH-H = 73 Hz 2H m-Ph) 751 (d 3JH-H = 74 Hz 2H o of C6H4CF3) 430 (s 2H

CH2) 13C1H NMR (125 MHz CD2Cl2) δ 1458 (ipso-C6H4CF3) 1404 (ipso-Ph) 1296 (p-Ph

o of C6H4CF3) 1285 (m-Ph) 1258 (p of C6H4CF3) 1256 (o-Ph) 1255 (m of C6H4CF3) 1239

(CF3) 415 (CH2) (JC-F not reported) GC-MS 11767 min mz = 2361 [M] 1671 [M-CF3]

1591 [M-C6H5] 911 [C7H7]

1-Benzyl-2-methylbenzene (Entry 7) 1H NMR (600 MHz CD2Cl2) δ

776 (m 2H o-Ph) 767 - 761 (m 3H m p-Ph) 759 - 754 (m 4H

C6H4CH3) 438 (s 2H CH2) 270 (s 3H CH3) 13C1H NMR (151

MHz CD2Cl2) δ 1410 (ipso-Ph) 1393 (ipso-C6H4CH3) 1370 (C-CH3) 1307 (C1) 1303 (m-

Ph) 1292 (o-Ph) 1287 (C4) 1268 (p-Ph) 1263 (C3) 1262 (C2) 395 (CH2) 197 (CH3)

GC-MS 12844 min mz = 1821 [M] 1671 [M-CH3]

130

1011-Dihydro-5H-dibenzo[ad][7]annulene (Scheme 312 b) 1H NMR

(600 MHz CD2Cl2) δ 745 (m 1H H2) 742 (m 1H H4) 740 (m 2H

H3 H5) 438 (s 1H CH2) 342 (s 2H CH2) 13C1H NMR (125 MHz

CD2Cl2) δ 1423 (C6) 1395 (C1) 1298 (C5) 1291 (C2) 1268 (C4) 1263 (C3) GC-MS

15761 min mz = 1941 [M] 1791 [M-CH3] 1651 [M-C2H5]















2) and Fo










131


Table 36 ndash Selected crystallographic data for 31

31 (+05 C6D5Br)

Formula C43H295B1Br05F20O2

Formula wt 100893

Crystal system monoclinic

Space group P2(1)c

a(Aring) 127865(6)

b(Aring) 199241(9)

c(Aring) 170110(7)

α(ordm) 9000

β(ordm) 1067440(10)

γ(ordm) 9000

V(Aring3) 41500(3)

Z 4

Temp (K) 150(2)

d(calc) gcm-3 1607

Abs coeff μ mm-1 0606

Data collected 37469

Rint 00368

Data used 9534

Variables 596

R (gt2σ) 00458

wR2 01145

GOF 1020

132

Chapter 4 Hydroamination and Hydrophosphination Reactions Using

Frustrated Lewis Pairs

41 Introduction

411 Hydroamination

The direct addition of N-H bonds to unsaturated organic compounds provides an atom-economic

route to valuable nitrogen-containing molecules Pursuit of such reactivity is largely motivated

by the ubiquitous nature of substituted amines in the pharmaceutical industry303-306 The

intermolecular hydroamination of alkynes represents an attractive single-step approach to

convert inexpensive and readily available starting materials to synthetic building blocks such as

imines and enamines

Intermolecular hydroamination of alkynes was initially carried out using Hg and Tl salts307-308

however toxicity concerns prompted subsequent development of a wide variety of other catalysts

based on rare-earth metals309 early- and late-transition metals303 310 as well as lanthanides311-312

and actinides313 Based on the pioneering work of Bergman314-316 and Doye317-318 group IV metal

derivatives have become popular catalysts in these reactions More recently the groups of

Richeson319 Odom320-321 Schafer322 Mountford323 and others311 313 321 324 have made significant

contributions to further the development of these catalysts

Nonetheless to date transition metal-free routes remain relatively less explored The Broslashnsted

acid tungstophosphoric acid has been reported by Lingaiah325 to catalyze the hydroamination of

alkynes However in order for this catalyst to operate harsh conditions and electronically

deactivated amines are required An alternative approach using a strong base such as cesium

hydroxide was reported by Knochel although this strategy only tolerated functional groups less

acidic than the amines309 More recently metal-free approaches have been demonstrated in the

work by Beauchemin on the Cope-type inter- and intramolecular hydroaminations326-329

133

412 Reactions of main group FLPs with alkynes

4121 12-Addition or deprotonation reactions

Recent research has been devoted to effect metal-free stoichiometric and catalytic

transformations using frustrated Lewis pairs (FLPs) These main group combinations of bulky

Lewis acids and bases have become the focus of a number of research groups worldwide330-331

Shortly after the discovery of FLP chemistry several reports communicated the organic

manipulation of alkynes analogous to the pioneering hydroboration reactions by H C Brown60

Initial studies showed that FLPs comprised of B(C6F5)3 or Al(C6F5)3(PhMe) and phosphines react

to yield either zwitterionic vinyl phosphonium borate or aluminate salts resulting from a 12-

addition reaction or phosphonium alkynylborates resulting from alkyne deprotonation126 128 The

course of the reaction was found to depend on the basicity of the phosphine donor with less

basic aryl phosphines favouring 12-addition (Scheme 41)


phenylacetylene to give 12-addition or deprotonation products (E = B or Al)

Berke and co-workers investigated related intermolecular reactions of terminal alkynes and

B(C6F5)3 with 26-lutidine and TMP demonstrating that these systems effect deprotonation of the

alkyne affording ammonium alkynylborates156 Alternatively the groups of Erker and Stephan

reported the intramolecular cyclization of pendant alkyne substituted anilines151 and N-

heterocycles152 via 12-addition reactions using B(C6F5)3 (Scheme 42 a and b) In a similar

fashion ethylene-linked sulphurborane systems were found to add to alkynes with subsequent

elimination of ethylene affording a single-step route to SB alkenyl-FLPs (Scheme 42 c)332

134



phenylacetylene generating SB alkenyl-FLPs (c)

4122 11-Carboboration reactions

The groups of Berke and Erker separately studied the reactivity of Lewis acids with alkynes in

the absence of a Lewis base (Scheme 43) To this extent they identified the 11-carboboration

reaction to generate alkenylboranes156 159-160 Moreover the reaction of propargyl esters with

B(C6F5)3 have been shown to generate boron allylation reagents333


alkenylboranes

135

4123 Hydroelementation reactions

Catalytic hydroelementation reactions have been reported for alkynes In the presence of 5 - 10

mol B(C6F5)3 internal alkynes have been shown to undergo both hydrostannylation334 (Scheme

44 a) and hydrogermylation335 reactions (Scheme 44 b)

Scheme 44 ndash B(C6F5)3 catalyzed hydrostannylation (a) and hydrogermylation (b) of alkynes

413 Reactions of transition metal FLPs with alkynes

The FLP paradigm has also been studied using transition metal systems in combination with

alkynes Some examples include metalation through the 11-carbozirconation336 and

boroauration337 reactions Additionally the Wass group developed cationic zirconocene

phosphinoaryloxide complexes that selectively deprotonate terminal alkynes (Scheme 45)338 In

a recent paper the Stephan group has shown that Ru-acetylides act as carbon nucleophiles in

combination with Lewis acids to effect trans-addition to alkynes162

Scheme 45 ndash Reaction of zirconocene phosphinoaryloxide complexes with terminal alkynes

Inspired by the reactivity of FLPs with alkynes in this chapter the intermolecular reaction of

amines B(C6F5)3 and a versatile group of terminal alkynes is explored in hydroamination

reactions A catalytic approach to yield enamines and corresponding amines is described In

addition related systems are probed to accomplish stoichiometric and catalytic intramolecular

hydroaminations affording N-heterocycles Finally stoichiometric approaches to

hydrophosphination reactions are discussed

136


421 Stoichiometric intermolecular hydroamination and deprotonation of terminal alkynes

With the objective of initiating hydroamination reactivity the three component stoichiometric

reaction of Ph2NH B(C6F5)3 and phenylacetylene was performed in CD2Cl2 The 1H 11B and 19F

NMR spectra revealed consumption of two equivalents of phenylacetylene to afford the salt

[Ph2N=C(CH3)Ph][PhCequivCB(C6F5)3] 41 while leaving a portion of the starting materials Ph2NH

and B(C6F5)3 unreacted (Scheme 46) Adjustment of the alkyne stoichiometry to two equivalents

afforded 41 in 90 yield (Table 41 entry 1) This new species results from the sequential

hydroamination and deprotonation reaction of phenylacetylene


The 1H NMR spectrum displayed a diagnostic methyl singlet at 289 ppm with the corresponding 13C1H resonance at 283 ppm In addition a downfield 13C1H resonance at 1901 ppm is

attributable to the iminium N=C group The alkynylborate anion [PhCequivCB(C6F5)3]- gave rise to

the 11B NMR signal at -208 ppm and 19F resonances at -1327 -1638 and -1673 ppm The

nature of compound 41 was unambiguously confirmed by X-ray crystallography (Figure 41)


137

To probe the generality of this reaction the corresponding reactivity of various substituted

secondary anilines with two equivalents of phenylacetylene were explored In this fashion the

species [RPhN=C(CH3)Ph][PhCequivCB(C6F5)3] (R = iPr 42 Cy 43 PhCH2 44 p-CH3O 45) were

isolated in 88 91 82 and 90 yield respectively (Table 41 entry 1) 1H NMR spectra

showed the iminium cations were formed as a mixture of the E and Z isomers in a 71 ratio for

compounds 42 and 43 41 ratio for 44 and 11 ratio for 45

Analogous reactions of Ph2NH B(C6F5)3 and two equivalents of 1-hexyne revealed two

competitive reaction pathways In addition to the hydroaminationdeprotonation product

[Ph2N=C(CH3)Bu][BuCequivCB(C6F5)3] 46 (Table 41 entry 2) the alkenylboranes resulting from

the 11-carboboration of 1-hexyne were also observed by NMR spectroscopy Exposing the same

anilineB(C6F5)3 combination to 9-ethynylphenanthrene produced [Ph2N=C(CH3)C14H9]

[C14H9CequivCB(C6F5)3] 47 in 75 isolated yield (Table 41 entry 3) The molecular structure of

47 was unambiguously characterized by X-ray crystallography (Figure 42)


138


139

In a similar fashion the reaction of two equivalents of ethynylcyclopropane with B(C6F5)3 and

iPrPhNH at room temperature afforded the yellow crystalline solid formulated as

[iPrPhN=C(CH3)C3H5][C3H5CequivCB(C6F5)3] 48 in 88 yield (Table 41 entry 4) In this case

the 1H NMR spectrum showed the iminium cation is formed as a mixture of the E and Z isomers

in a 17 ratio Furthermore the reaction of iPrPhNHB(C6F5)3 with 2-ethynylthiophene

proceeded cleanly to give the product [iPrPhN=C(CH3)C4H3S][C4H3SCequivCB(C6F5)3] 49

obtained as a 71 mixture of EZ isomers and isolated in 78 yield (Table 41 entry 5) Single

crystals suitable for X-ray diffraction were obtained for Z-48 and Z-49 and the structures are

shown in Figure 43 (a) and (b) respectively

Figure 43 ndash POV-Ray depiction of Z-48 (a) and Z-49 (b)

Interestingly addition 14-diethynylbenzene to the stoichiometric combination of Ph2NH

B(C6F5)3 resulted in an instant color change from pale orange to deep red affording the

zwitterionic product [Ph2N=C(CH3)C6H4CequivCB(C6F5)3] 410 in 85 yield (Table 41 entry 6)

The molecular structure of 410 was confirmed by X-ray crystallography (Figure 44)


(a) (b)

140

4211 Proposed mechanism for the hydroamination and deprotonation reactions of terminal alkynes

The three component reaction is thought to proceed via Lewis acid polarization of the alkyne by

B(C6F5)3 prompting nucleophilic addition of the aniline and generating a zwitterionic

intermediate (Scheme 47) Analogous 12-additions to alkynes have been previously reported for

phosphineborane126 128 thioetherborane339 and pyrroleborane127 FLPs However in the present

study the arylammonium intermediate provides an acidic proton which cleaved the B-C bond

yielding enamine with concurrent release of B(C6F5)3 Subsequent to this hydroamination the

FLP derived from enamine and B(C6F5)3 deprotonate a second equivalent of the alkyne affording

the isolated iminium alkynylborate salts (Scheme 47)


generating iminium alkynylborate salts

Analogous stoichiometric combination of tert-butylaniline or diisopropylamine and B(C6F5)3

with either one or two equivalents of phenylacetylene resulted exclusively in deprotonation of

the terminal alkyne affording the ammonium alkynylborate salts [tBuPhNH2][PhCequivCB(C6F5)3]

411 and [iPr2NH2][PhCequivCB(C6F5)3] 412 in 99 and 76 yield respectively (Scheme 48) In

these cases the amines are sufficiently bulky to form a FLP with B(C6F5)3 and relatively basic to

preferentially effect deprotonation of the alkyne This reaction pathway has been previously

observed for basic phosphines and B(C6F5)3 with numerous alkynes

141

Scheme 48 ndash Deprotonation of phenylacetylene by diisopropylamine and B(C6F5)3

4212 Reactivity of amineborane FLPs with internal alkynes and other unsaturated substrates

In separate reactions FLPs comprised of iPrNHPhB(C6F5)3 and Ph2NHB(C6F5)3 were

combined with the internal alkynes 3-hexyne diphenylacetylene and 1-phenyl-1-propyne At

RT multinuclear NMR data only revealed signals for the FLP and unaltered alkyne Heating

the reactions up to 80 degC did not display signals for hydroamination rather only products of 11-

carboboration were observed

Also interested in extending the unsaturated substrates scope the hydroamination of the olefins

1-hexene cyclohexene styrene αp-dimethylstyrene and 3-(trifluoromethyl)styrene were tested

using the FLPs iPrNHPhB(C6F5)3 and Ph2NHB(C6F5)3 Thermolysis of the individual samples

up to 100 degC only revealed signals for the starting materials

4213 Reactivity of the iminium alkynylborate products with nucleophiles

An attractive feature of the iminium cation is the unsaturated N=C fragment since it could be

reacted with nucleophiles to give amines and this transformation could potentially be extended to

generate enantioselective variants of the amines Introducing simple fluoride sources such as

[NBu4][Si(Ph)3F2] NBu4F and CsF to compounds 42 and 46 resulted in deprotonation of the

methyl group losing HF and generating the corresponding enamine Nonetheless addition of the

H+ source [(Et2O)2H][B(C6F5)4]287 regenerated the iminium cation (Scheme 49)


with [(Et2O)2H][B(C6F5)4]

142

Furthermore addition of the organolithium reagents methyl lithium and ethyl lithium at -30 degC

gave a 11 mixture of the alkylation and deprotonation products as evidenced by 1H NMR

spectroscopy while phenyl lithium did not result in any reactivity (Scheme 410 left)

Combinations of stoichiometric hydride sources [tBu3PH][HB(C6F5)3] NaBHEt3 and LiAlH4

only gave saturation of the N=C bond with the lithium reducing agent (Scheme 410 right)

Overall while hydride delivery to the N=C bond was successfully achieved inefficient delivery

of the presented alkyl and aryl nucleophiles shifted focus towards other types of reactivities

Scheme 410 ndash Reaction of 42-cation with organolithium sources (left) and LiAlH4 (right)

422 Friedel-Crafts hydroarylation of phenylacetylene using aromatic amines and B(C6F5)3

The equimolar reaction of the tertiary amine dibenzylaniline B(C6F5)3 and phenylacetylene was

investigated with the aim of isolating a zwitterionic intermediate analogous to the compound

proposed en route to hydroamination in Scheme 47 In this case however the nucleophilic

centre for this reaction proved to be the para-carbon of the N-bound phenyl ring undergoing

hydroarylation of phenylacetylene to generate the zwitterionic species

(PhCH2)2NHC6H4C(Ph)=C(H)B(C6F5)3 413 in 96 yield (Scheme 411) Single crystal X-ray

diffraction confirmed the structure of 413 and it is shown in Figure 45 (a)


dibenzylaniline and B(C6F5)3

143

Examining the secondary amine N-isopropylanthracen-9-amine in similar reactivity also gave the

hydroarylation of phenylacetylene and this was demonstrated at the C10 position of the

anthracene ring forming iPr(H)N=C14H9C(Ph)=C(H)B(C6F5)3 414 in 95 yield In this unique

case however a N=C double bond is generated between nitrogen and the anthracene ring as well

as saturation of the C10 centre giving the tetrahedral geometry observed in the solid state

structure of 414 shown in Figure 45 (b) Generally aromatic substitution reactions in the

presence of Lewis acids have been used for the synthesis of numerous aromatic molecules340

Particularly relevant to this thesis the para-carbon of N-bound phenyl rings has been proposed

as the Lewis basic centre to heterolytically split H2 and generate a sp3-hybridized carbon centre

in the arene hydrogenation reactions presented in Chapter 2


length 1305(5)Aring bond angle iPrC-N=Canthracene 1328deg

Stability of the B-C bond towards acidic conditions was tested In this regard combinations of

413 with the protic salts [(Et2O)2H][B(C6F5)4] or [Ph2NH2][B(C6F5)4] were found to readily

cleave the B-C bond liberating B(C6F5)3 and generating the diphenylethylene-ammonium

derivative as evidenced by the geminal protons at 508 and 504 ppm in the 1H NMR spectrum

(Scheme 412)

(a) (b)

144


[Ph2NH2][B(C6F5)4] to cleave the B-C bond

423 B(C6F5)3 catalyzed intermolecular hydroamination of terminal alkynes

With the exception of catalytic hydrogenations the majority of FLPs reported to date react with

small molecules in a stoichiometric fashion Thus seeking to expand the application of FLPs in

catalysis beyond hydrogenations attention was turned to the development of catalytic

hydroamination reactions This motivation was inspired by the hydroaminationdeprotonation

mechanism proposed in Scheme 47 Realizing that deprotonation of alkyne eliminates the

possibility for catalysis the reaction protocol was adjusted in which the alkyne is added slowly

in order to achieve hydroamination and prevent deprotonation by enamine and B(C6F5)3

The slow addition of the terminal alkyne 2-ethynylanisole to a RT solution of Ph2NH and 10

mol of B(C6F5)3 in toluene over 10 h afforded the catalytic hydroamination product 2-

methoxyphenyl substituted enamine Ph2N(2-MeOC6H4)C=CH2 415 in 84 isolated yield (Table

42) The 1H NMR spectrum of 415 displayed two diagnostic singlets at 501 and 490 ppm

characteristic of the inequivalent geminal hydrogen atoms The corresponding carbon centre

gives rise to a 13C1H NMR signal at 108 ppm Further NMR studies of the compound were

consistent with formation of the Markovnikov isomer in which the nitrogen is added to the

substituted carbon of the terminal alkyne

The analogous treatment of Ph2NH with 2-ethynyltoluene in the presence of 10 mol B(C6F5)3

afforded Ph2N(2-MeC6H4)C=CH2 416 in 69 isolated yield while the alkyne 1-

ethynylnaphthalene yielded Ph2N(C10H7)C=CH2 417 in 62 yield (Table 42) The

corresponding reaction of Ph2NH with phenylacetylene and 2-bromo-phenylacetylene afforded

Ph2N(C6H5)C=CH2 418 and Ph2N(2-BrC6H4)C=CH2 419 in yields of 74 and 52 respectively

(Table 42) Similar to 415 the 1H and 13C1H NMR data for these products were in agreement

with the proposed product formulations

145

Table 42 ndash Intermolecular hydroamination reactions catalyzed by B(C6F5)3

This hydroamination strategy also proved effective for substituted diphenylamines For example

(p-FC6H4)2NH in combination with 10 mol B(C6F5)3 reacted with halogenated

phenylacetylenes to afford the species (p-FC6H4)2N(2-BrC6H4)C=CH2 420 and (p-FC6H4)2N(2-

146

FC6H4)C=CH2 421 while the corresponding reactivity with 2-thiophenylacetylene gave (p-

FC6H4)2N(2-SC4H3)C=CH2 422 and iPrPhN(2-SC4H3)C=CH2 423 when reacted with iPrNHPh

(Table 42)

The reaction of Ph2NH with 9-ethynylphenanthrene gave Ph2N(C14H9)C=CH2 424 and (p-

FC6H4)2NH was used to prepare (p-FC6H4)2N(C14H9)C=CH2 425 Similarly reactions of the

appropriate combinations of amine and alkyne using 10 mol B(C6F5)3 afforded (p-FC6H4)2N(3-

FC6H4)C=CH2 426 Ph2N(35-F2C6H3)C=CH2 427 and Ph2N(3-CF3C6H4)C=CH2 428 although

in these cases cooling to -30 degC was necessary to maximize yields obtained between 68 - 77

(Table 42) This impact of temperature was most dramatically demonstrated in the case of 426

where performing the reaction at 25 degC gave the product in 19 yield while at -30 degC the yield

was significantly enhanced to 74

4231 Proposed mechanism for B(C6F5)3 catalyzed intermolecular hydroamination reactions

The success of these hydroamination reactions strongly depends on the electronic and steric

nature of the amineborane FLP combination thereby preventing 11-carboboration and

deprotonation of the alkyne Interaction of the borane with the terminal alkyne prompts amine

addition to generate a zwitterionic intermediate In the present case the acidic proton of the

anilinium centre migrates to the carbon adjacent to boron cleaving the B-C bond and forming the

enamine product (Scheme 413) The released B(C6F5)3 is then available to participate in further

hydroamination catalysis It is noteworthy that the postulated zwitterion accounts for the

Markovnikov addition of amines to alkynes and thus the nature of the observed enamine

products341

As stated earlier catalytic formation of enamine requires the slow addition of alkyne over 10 h

This is a result of deprotonation of the alkyne by the FLP derived from enamine and borane

consequently generating iminium alkynylborate salts analogous to 42 - 410 The observed

catalytic hydroaminations imply that amine addition to alkyne is faster than enamine

deprotonation of alkyne

147


alkynes

4232 One-pot catalytic hydroamination and hydrogenation reactions of terminal alkynes

The catalytic generation of these enamines together with previously established FLP

hydrogenation of enamines93 prompted interest in a one-pot catalytic

hydroaminationhydrogenation protocol

Following the hydroamination procedure described above reaction mixtures generating the two

enamines 421 and 427 were exposed to H2 (4 atm) and heated at 80 degC for 14 h Pleasingly the

B(C6F5)3 catalyst successfully completed hydrogenation of the C=C double bond giving the

amines (p-FC6H4)2N(2-FC6H4)C(H)CH3 429 and Ph2N(35-F2C6H3)C(H)CH3 430 in 77 and

64 overall isolated yields respectively (Scheme 414) Monitoring the hydrogenation portion

of the reactions by 1H NMR spectroscopy revealed in both cases demise of the signals

attributable to the geminal protons of the enamines with simultaneous appearance of a quartet

attributable to the methine proton and a doublet assignable to the methyl group of the respective

amine In an alternative approach to the hydrogenation catalysis subsequent to hydroamination

5 mol of the known hydrogenation catalyst Mes2PH(C6F4)BH(C6F5)294 was added to the

reaction mixture pressurized with H2 (4 atm) and heated to 80 degC In both cases complete

hydrogenation was achieved after 3 h

148


429 and 430

Experimental evidence demonstrated the catalytic hydroaminations are restricted to aryl

acetylenes Examples of other terminal alkynes that were examined include

trimethylsilylacetylene which resulted in 11-carboboration while the acetylene carboxylates

methyl propiolate ethyl propiolate 2-naphthyl propiolate and tert-butyl propiolate did not react

due to formation of a B-O adduct Extending the chemistry to hydrothiolation using thiophenol

was not successful

424 Intramolecular hydroamination reactions using FLPs

4241 Stoichiometric hydroamination

The potential of the above hydroamination reactions to access N-heterocycles was also probed

To this end the alkynyl-substituted aniline C6H5NH(CH2)3CequivCH was prepared and exposed to

an equivalent of B(C6F5)3 in toluene 11B NMR spectroscopy indicated the formation of a B-N

adduct verified by the resonance at -25 ppm although heating the reaction for 2 h at 50 degC

yielded the cyclized zwitterion C6H5N(CH2)3CCH2B(C6F5)3 431 isolated as a white solid in 94

yield (Scheme 415) The 1H NMR spectrum was consistent with consumption of the NH proton

revealing a diagnostic broad quartet at 333 ppm with geminal B-H coupling of 54 Hz indicative

of the B(C6F5)3 bound methylene group In addition a diagnostic sharp singlet at -134 ppm in

149

the 11B NMR spectrum and the N=C iminium 13C1H resonance at 192 ppm were consistent

with the formulation of 431


generate 431 and 432

The analogous 6-membered ring was prepared from the precursor C6H5NH(CH2)4CequivCH and an

equivalent of B(C6F5)3 giving the zwitterion C6H5N(CH2)4CCH2B(C6F5)3 432 in 99 yield The

formulation of 432 was affirmed by NMR spectroscopy in addition to elemental analysis and X-

ray crystallography (Figure 46)


Similarly substituted isoindoline species are accessible from the reaction of the precursor

C6H5NHCH2(C6H4)CequivCH with B(C6F5)3 in toluene Stoichiometric combination of the two

reagents resulted in a white precipitate believed to be the intramolecular hydroamination product

after 10 min at RT However this compound was sparingly soluble in toluene bromobenzene

and CD2Cl2 not allowing its comprehensive characterization by NMR spectroscopy As such H2

(4 atm) was added to the reaction and heated at 80 degC for 16 h in an effort to synthesize the H2

activated salt which was presumed to be more soluble than the zwitterion The 1H NMR

150

spectrum of this reaction displayed a quartet at 556 ppm and a triplet at 289 ppm with a four-

bond coupling constant of 26 Hz 13C1H NMR data showed a resonance at 182 ppm

attributable to a N=C bond Collectively these data are consistent with the successive

hydroamination and hydrogenation product [2-MeC8H6N(Ph)][HB(C6F5)3] 433 isolated in 54

yield (Scheme 416)


C6H5NHCH2(C6H4)CequivCH and B(C6F5)3 to generate 433

While species 433 is isolated as an insoluble solid from pentane in CD2Cl2 the [HB(C6F5)3]-

anion appears to reversibly deliver hydride to the N=C carbon centre generating isoindoline and

B(C6F5)3 in about 25 This was evidenced by 1H NMR spectroscopy revealing a diagnostic

quartet at 518 ppm two diastereotopic doublets at 472 and 455 ppm and an upfield doublet at

151 ppm data that is collectively assignable to the isoindoline species This was further

supported by 11B and 19F NMR spectroscopy which provided evidence of free B(C6F5)3 Presence

of this equilibrium is consistent with a previous report on reversible hydride abstraction and

redelivery from carbon centres alpha to nitrogen262

4242 B(C6F5)3 catalyzed intramolecular hydroamination to generate cyclized amines

This hydroaminationhydrogenation protocol was further adapted for catalytic cyclization

reactions In this fashion the alkynyl substituted aniline C6H5NH(CH2)3CequivCH was treated with

10 mol B(C6F5)3 at 80 degC under H2 (4 atm) for 16 h This gave the desired product 2-methyl-1-

phenyl pyrrolidine 434 in 68 isolated yield (Table 43 entry 1) In a similar fashion the

catalytic hydroaminationhydrogenation of C6H5NH(CH2)4CequivCH gave 2-methyl-1-

phenylpiperidine 435 in 66 yield (Table 43 entry 2) The following protocol was also

applicable to p-fluoro and p-methoxy substituted substrates giving the respective cyclized

products 436 and 437 in 72 and 52 yield respectively (Table 43 entries 3 and 4) Finally

151

similar reactivity with C6H5NHCH2(C6H4)CequivCH gave 1-methyl-2-phenylisoindoline 438 in 70

yield (Scheme 417)

The yields obtained for compounds 436 and 437 strongly reflect the balance of Broslashnsted acidity

required by the amine proton to effect hydroamination In this case the p-fluoro substituent

proved more effective in hydroamination than p-methoxy


anilines generating cyclized amines

Entry R n Isolated yield

1 H 0 68 434

2 H 1 66 435

3 F 1 72 436

4 CH3O 1 52 437


C6H5NHCH2(C6H4)CequivCH

425 Reaction of B(C6F5)3 with ethynylphosphines

The stoichiometric reaction of B(C6F5)3 with the ethynylphosphine tBu2PCequivCH has previously

been shown to give the deprotonation product tBu2P(H)CequivCB(C6F5)3342 Conversely analogous

treatment of Mes2PCequivCH required addition of tBu3P to effect deprotonation of the ethynyl group

due to diminished Lewis basicity of the phosphine Moreover the Erker group reported the

152

reaction of Ph2PCequivCH with B(C6F5)3 to generate a dimeric product formed by a sequential series

of 12-PB additions to the ethynyl unit343

While interested in hydroamination of ethynylphosphines the FLP iPrNHPhB(C6F5)3 was added

to two equivalents of Mes2PCequivCH giving the pale yellow solid 439 in 88 yield (Scheme 418)

The 1H NMR spectrum did not indicate incorporation of aniline into the product rather two

inequivalent vinylic protons with characteristic P-H and H-H coupling were observed at 771 and

574 ppm (Figure 47)


the zwitterion 439


439 with insets focusing on the vinylic protons

The 31P NMR spectrum revealed two resonances with chemical shifts at -115 and -143 ppm

while the 11B and 19F NMR spectra were in agreement with formation of an alkynylborate

species (11B δ -211 ppm 19F δ -1329 -1616 and -1663 ppm) These data together with

elemental analysis confirm the formulation of the zwitterionic species trans-

Mes2PC(H)=C(H)Mes2PCequivCB(C6F5)3 439 An X-ray crystallographic study confirmed the

1H

1H31P

153

molecular structure of 439 and it is shown in Figure 48 (a) In the absence of aniline the

reaction leads to the previously reported 11-carboboration product344-345

On another account the same reaction was obtained with 2 equivalents of tBu2PCequivCH and

B(C6F5)3 to give cis and trans isomers of tBu2PC(H)=C(H)tBu2PCequivCB(C6F5)3 440 The cis

isomer was crystallized and characterized by X-ray diffraction studies (Figure 48 b) In this

case the phosphorus centre was basic enough to effect deprotonation thus the reaction proceeded

in the absence of iPrNHPh Monitoring the reaction by 31P NMR spectroscopy the spectrum

indicated the simultaneous presence of tBu2PCequivCH and the deprotonation zwitterion

tBu2P(H)CequivCB(C6F5)3 giving insight to a plausible mechanism en route to the formation of

compounds 439 and 440

Figure 48 ndash POV-Ray depictions of 439 (a) and 440 (b)

4251 Proposed mechanism for reaction of B(C6F5)3 and ethynylphosphines

The reaction is proposed to proceed through the mechanism highlighted in Scheme 419 wherein

the mixture of B(C6F5)3 and R2PCequivCH initially effect deprotonation of the ethynyl group

formulating the zwitterion R2P(H)CequivCB(C6F5)3 Under equilibrium conditions a second

equivalent of the ethynylphosphine is protonated consequently prompting nucleophilic addition

of the [R2PCequivCB(C6F5)3]- anion to the terminal carbon followed by proton transfer to generate

the isolated zwitterionic products In the case of Mes2PCequivCH the deprotonation step required a

stronger base therefore iPrNHPh was added to effect reactivity

(a) (b)

154


generate the vinylic zwitterions 439 and 440

426 Stoichiometric hydrophosphination of acetylenic groups using FLPs

An earlier report showed the three component reaction of p-tolyl2PH B(C6F5)3 and

phenylacetylene gave the 12-addition phosphonium borate zwitterion p-

tolyl2PH(Ph)C=C(H)B(C6F5)3128 Realizing the acidic hydrogen on the phosphorus atom a

sample of this compound was treated by UV radiation or heated to prompt hydrophosphination

of phenylacetylene in a mechanism analogous to that presented for the hydroamination reaction

In this regard however the zwitterion proved robust and further reactivity was not observed

Similar results were obtained when using Mes2PH or exchanging the borane for the slightly less

Lewis acidic B(p-C6F4H)3

Turning attention towards the borane HB(C6F5)2 the hydrophosphination reaction was attempted

following an alternative approach In this regard Ph2PH was added to a stoichiometric

combination of HB(C6F5)2 and Bpin-substituted 1-hexyne (Scheme 420 a) After 16 h at RT

the acetylenic unit of Bpin was reduced to a C-C single bond as illustrated by a characteristic

multiplet at 353 ppm and a very broad singlet at 148 ppm in the 1H NMR spectrum The

product Bu(H)Ph2PC-C(H)B(C6F5)2Bpin 441 resulting from the sequential hydroboration and

hydrophosphination reactions was isolated in 82 yield NMR spectroscopy data indeed showed

incorporation of all reactants into the isolated product

155



Ph2PH

Investigating similar reactivity of 2-methyl-1-buten-3-yne substituted Bpin with HB(C6F5)2 and

Ph2PH a colourless solid was obtained in 73 yield The 1H NMR data unambiguously showed

saturation of the acetylenic fragment however the spectrum consisted of an olefinic proton at

646 ppm in addition to a methylene group at 307 ppm Further spectroscopic data revealed the

product as Ph2PCH2(CH3)C=CHC(H)B(C6F5)2Bpin 442 resulting from nucleophilic addition of

the phosphine at the terminal double bond (Scheme 420) Single crystals suitable for X-Ray

diffraction were obtained and the structure is shown in Figure 49 (b)

Figure 49 ndash POV-Ray depictions of 442

156

427 Proposed mechanism for the hydroborationhydrophosphination reactions

The mechanism of this reaction is envisaged to initiate following the well-documented

hydroboration of the acetylenic group generating the corresponding alkenyl-bisborane species

(Scheme 421)346 At this point the phosphine coordinates to B(C6F5)2 rendering its proton more

Broslashnsted acidic and prompting protonation of the C=C double bond This is followed by

nucleophilic attack of the phosphine at the C2 position of alkynyl-substituted Bpin (441) or C4

position of the enyne-substituted Bpin (442) The 14-addition reaction to conjugated enynes has

been previously investigated using the ethylene-linked PB FLP to give eight membered cyclic

allenes147


reactions of Bpin substrates consisting of acetylenic fragments

Since evidence for the P-B intermediate is not observed by 11B or 31P NMR spectroscopy an

alternative mechanism could be speculated In this case the nucleophilic phosphine could add to

the vinyl bisborane followed by proton transfer However this later mechanism is not highly

supported as the more Lewis basic secondary phosphines tBu2PH and iPr2PH only gave the P-B

adduct with HB(C6F5)2 consistent with retro-hydroboration after coordination of the phosphine

to the vinyl bisborane This adduct remained intact even at elevated temperatures of 80 degC

Similar N-B adducts were observed when the analogous reactivity was explored with the alkyl

and aryl amines iPr2NH iPrNHPh and Ph2NH

157

43 Conclusions

This chapter provides an account on the discovery of consecutive hydroamination and

deprotonation reactions of various terminal alkynes by anilineB(C6F5)3 FLPs to form a series of

iminium alkynylborate complexes The reaction procedure was modified to eliminate the

deprotonation step in order to achieve B(C6F5)3 catalyzed Markovnikov hydroamination of

alkynes yielding enamine products Subsequent to hydroamination catalysis the borane catalyst

was also used for catalytic hydrogenation of the enamine providing a one-pot avenue to the

corresponding amine derivatives Related systems were probed to accomplish the stoichiometric

and catalytic intramolecular hydroamination of alkynyl-substituted anilines generating cyclic

amines While this hydroamination protocol was not extendable to effect hydrophosphination a

new stoichiometric approach using HB(C6F5)2 and Ph2PH was found to result in the sequential

hydroboration and hydrophosphination reactions of an alkynyl- and enynyl-substituted

pinacolborane generating novel PB FLPs





freezer) Pentane dichloromethane and toluene (Sigma Aldrich) were dried employing a Grubbs-

type column system (Innovative Technology) degassed and stored over molecular sieves (4 Aring)

in the glovebox Dichloromethane-d2 bromobenzene-d5 and bromobenzene-H5 were purchased

from Sigma Aldrich and dried over CaH2 for several days and vacuum distilled onto 4 Aring

molecular sieves prior to use Hexane and ethyl acetate were purchased from Caledon

Laboratories Silica gel was purchased from Silicycle Molecular sieves (4 Aring) were purchased

from Sigma Aldrich and dried at 120 ordmC under vacuum for 24 h prior to use B(C6F5)3 was

purchased from Boulder Scientific and sublimed at 80 degC under high vacuum before use H2

(grade 50) was purchased from Linde and dried through a Nanochem Weldassure purifier

column prior to use

Substituted amines alkynes and phosphines were purchased from Sigma Aldrich Alfa Aesar

Apollo Scientific Strem Chemicals Inc and TCI The oils were distilled over CaH2 and solids

were sublimed under high vacuum prior to use The following reagents were prepared following

158

literature procedures 1-ethynylnaphthalene347 (p-C6H4F)2NH (p-CH3OC6H4)PhNH tBuNHPh

and N-isopropylanthracen-9-amine266 N-(2-ethynylbenzyl)aniline N-(pent-4-ynyl)aniline N-

(hex-5-ynyl)aniline 4-fluoro-N-(hex-5-yn-1-yl)aniline and 4-methoxy-N-(hex-5-yn-1-

yl)aniline348 N-(2-ethynylbenzyl)aniline349 tBu2PCequivCH and Mes2PCequivCH342

CH3(CH2)3CequivCBpin and CH2=C(CH3)CequivCBpin350

Compounds 439 - 442 were prepared by the author during a four month research opportunity in

the group of Professor Gerhard Erker at Universitaumlt Muumlnster Germany Molecular structures and

elemental analyses for 439 and 440 were obtained at the University of Toronto Molecular

structure for 442 was obtained at Universitaumlt Muumlnster and elemental analyses for 441 and 442

were obtained at the University of Toronto



referenced to residual solvent of C6D5Br (1H = 728 ppm for meta proton 13C = 1224 ppm for

ipso carbon) and CD2Cl2 (1H = 532 ppm 13C = 5384 ppm) or externally (11B (Et2O)BF3 19F

CFCl3) Chemical Shifts (δ) are reported in ppm and the absolute values of the coupling

constants (J) are in Hz NMR assignments are supported by additional 2D and DEPT-135

experiments

High resolution mass spectra (HRMS) were obtained using an ABSciex QStar Mass

Spectrometer with an ESI source MSMS and accurate mass capabilities Elemental analyses (C

H N) were performed in-house employing a Perkin Elmer 2400 Series II CHNS Analyzer


4421 Procedures for stoichiometric intermolecular hydroamination reactions

Compounds 41 - 45 were prepared in a similar fashion thus only one preparation is detailed In

the glove box a 4 dram vial equipped with a stir bar was charged with a solution of B(C6F5)3

(0379 g 0740 mmol) and the respective amine (0740 mmol) To the vial phenylacetylene (151

mg 148 mmol) was added drop wise over 1 min In the case where pentane was used as the

solvent the reaction was worked up as follows the solvent was decanted and the product was

washed with pentane (3 times 5 mL) to yield the product as a solid In the case where toluene or

159

dichloromethane was used as the as solvent the reaction was worked up as follows the solvent

was removed under reduced pressure and the crude product was washed with pentane to yield the

product as a solid

Synthesis of [Ph2N=C(CH3)Ph][PhCequivCB(C6F5)3] (41) Diphenylamine (0125 g 0740

mmol) pentane (20 mL) reaction time 2 h yellow solid (588 mg 0666 mmol 90) Crystals


-30 ordmC

1H NMR (400 MHz CD2Cl2) δ 768 (m 3H H4 H5) 761 (m 1H p-Ph)

745 (m 5H o m p-Ph) 739 (m 4H H3 m-Ph) 728 (dm 3JH-H = 75

Hz 2H H7) 717 (tm 3JH-H = 75 Hz 2H H8) 711 (tm 3JH-H = 75 Hz

1H H9) 710 (dm 3JH-H = 77 Hz 2H o-Ph) 289 (s 3H Me) 19F NMR

(377 MHz CD2Cl2) δ -1327 (m 2F o-C6F5) -1638 (t 3JF-F = 21 Hz 1F

p-C6F5) -1673 (m 2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ -208 (s

equivCB) 13C1H NMR (151 MHz CD2Cl2) δ 1901 (C1) 1352 (p-Ph) 1320 (C5) 1315 (C4)

1312 (p-Ph) 1310 (C7) 1307 (m-Ph) 1298 (Ph) 1293 (Ph) 1277 (C8) 1257 (C9) 1254 (o-

Ph) 1241 (C3) 283 (Me) (C2 C6 ipso-Ph and all carbons for CequivCB(C6F5)3 were not

observed) Elemental analysis was not successful after numerous attempts

Synthesis of E-[iPrPhN=C(CH3)Ph][PhCequivCB(C6F5)3] (42) N-Isopropylaniline (100 mg

0740 mmol) pentane (10 mL) reaction time 1 h pale yellow solid (566 mg 0651 mmol 88)

EZ ratio 71

42 1H NMR (400 MHz CD2Cl2) δ 773 (tm 3JH-H = 77 Hz 1H H5)

772 (m 6H H4 H9 H10) 746 (dm 3JH-H = 77 Hz 2H H3) 728 (dm 3JH-H = 76 Hz 2H H12) 720 (m 2H H8) 716 (t 3JH-H = 76 Hz 2H

H13) 713 (t 3JH-H = 76 Hz 1H H14) 491 (m 3JH-H = 66 Hz 1H H6)

244 (s 3H Me) 126 (d 3JH-H = 66 Hz 6H iPr) 19F NMR (377 MHz

CD2Cl2) δ -1327 (m 2F o-C6F5) -1637 (t 3JF-F = 20 Hz 1F p-C6F5) -1672 (m 2F m-C6F5)

11B NMR (128 MHz CD2Cl2) δ -209 (s equivCB) 13C1H NMR (101 MHz CD2Cl2) δ 1913

(C1) 1482 (dm 1JC-F = 236 Hz CF) 1381 (dm 1JC-F = 243 Hz CF) 1365 (dm 1JC-F = 245 Hz

CF) 1346 (C2) 1339 (C5) 1319 (C10) 1318 (C7) 1311 (C12) 1310 (C4) 1303 (C9) 1278

(C13) 1274 (C11) 1258 (C14) 1253 (C3 C8) 937 (C15) 619 (C6) 288 (Me) 208 (iPr)

160

(CequivCB(C6F5)3 and ipso-C6F5 were not observed) Anal calcd () for C43H25BF15N C 6066 H

296 N 165 Found 6037 H 317 N 173

Synthesis of E-[CyPhN=C(CH3)Ph][PhCequivCB(C6F5)3] (43) N-Cyclohexylaniline (135 mg

0740 mmol) pentane (10 mL) reaction time 1 h off-white solid (599 mg 0674 mmol 91)

EZ ratio 71

43 1H NMR (400 MHz CD2Cl2) δ 769 (tt 3JH-H = 74 Hz 4JH-H = 24

Hz 1H H5) 762 (m 5H H4 H12 H13) 737 (dm 3JH-H = 74 Hz 2H H3)

720 (dm 3JH-H = 77 Hz 2H H15) 711 (m 4H H11 H16) 703 (tm 3JH-H

= 77 Hz 1H H17) 439 (tt 3JH-H = 119 Hz 3JH-H = 35 Hz 1H H6) 235

(s 3H Me) 184 (dm JH-H = 117 Hz 1H H7) 170 (dm 2JH-H = 145 Hz

2H H8) 145 (dm 2JH-H = 132 Hz 2H H9) 133 (m 1H H7) 104 (pseudo qt JH-H = 138 Hz 3JH-H = 37 Hz 2H H8) 080 (pseudo qt 2JH-H = 132 Hz 3JH-H = 37 Hz 2H H9) 19F NMR


2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ -208 (s equivCB) 13C1H NMR (101 MHz

CD2Cl2) δ 1916 (C1) 1341 (C5) 1323 (C13) 1315 (C15) 1313 (C4) 1307 (C12) 1282 (C16)

1262 (C17) 1257 (C3) 1254 (C11) 699 (C6) 320 (C7) 291 (Me) 249 (C8) 244 (C9) (C2

C10 C14 and all carbons for CequivCB(C6F5)3 were not observed) Anal calcd () for C46H29BF15N

C 6197 H 328 N 157 Found 6158 H 354 N 153

Synthesis of E-[(PhCH2)PhN=C(CH3)Ph][PhCequivCB(C6F5)3] (44) N-Benzylaniline (135 mg

0740 mmol) dichloromethane (10 mL) reaction time 2 h pale yellow solid (544 mg 0607

mmol 82) EZ ratio 41

44 1H NMR (600 MHz CD2Cl2) δ 782 (t 3JH-H = 73 Hz 1H H5) 777

(t 3JH-H = 73 Hz 2H H4) 764 (d 3JH-H = 73 Hz 2H H3) 760 (t 3JH-H =

76 Hz 1H H14) 753 (t 3JH-H = 76 Hz 2H H13) 738 (m 1H H10) 728

(m 4H H9 H16) 716 (t 3JH-H = 73 Hz 2H H17) 710 (t 3JH-H = 73 Hz

1H H18) 699 (d 3JH-H = 76 Hz 2H H12) 679 (d 3JH-H = 76 Hz 2H

H8) 526 (s 2H H6) 259 (s 3H Me) 19F NMR (377 MHz CD2Cl2) δ -1326 (m 2F o-C6F5)


207 (s equivCB) 13C1H NMR (151 MHz CD2Cl2) δ 1912 (C1) 1386 (C7) 1342 (C5) 1339

(C2) 1317 (C11 C14) 1311 (C9) 1309 (C13 C15) 1304 (C4 C10) 1296 (C8) 1294 (C16) 1278

B(C6F5)3

N1

2

3

45

7

8

9

10

14

1516

17

18

6

11

12

13

B(C6F5)3

N1

2

3

45

7

8 9

10

11 12

13

14

1617

1815

6

19

161

(C17) 1263 (C3) 1258 (C18) 1241 (C8) 938 (C19) 645 (C6) 286 (Me) (CequivCB(C6F5)3 and all

carbons of B(C6F5)3 were not observed) Anal calcd () for C47H25BF15N C 6276 H 280 N

156 Found 6259 H 296 N 171

Synthesis of [(p-C6H4OMe)PhN=C(CH3)Ph][PhCequivCB(C6F5)3] (45) (p-CH3OC6H4)PhNH

(147 mg 0740 mmol) pentane (15 mL) room temperature reaction time 3 h yellow solid (493

mg 0540 mmol 73) Anal calcd () for C47H25BF15NO C 6166 H 275 N 153 Found C

6106 H 262 N 142 EZ ratio 11

1H NMR (500 MHz CD2Cl2) δ 756 (m 2H H7) 748 (m 1H H5) 735

(m 2H H3) 730 (m 2H H4) 726 (m 2H H8) 717 (m 2H H15) 707

(tm 3JH-H = 72 Hz 2H H16) 702 (m 1H H17) 696 (m 1H H9) 688

(dm 3JH-H = 87 Hz 2H H11) 670 (dm 3JH-H = 87 Hz 2H H12) 365 (s

3H OMe) 273 (s 3H Me) 19F NMR (377 MHz CD2Cl2) δ -1327 (m

2F o-C6F5) -1637 (t 3JF-F = 21 Hz 1F p-C6F5) -1672 (m 2F m-C6F5)


(C1) 1613 (C13) 1481 (dm 1JC-F = 241 Hz CF) 1421 (C6) 1381 (dm 1JC-F = 244 Hz CF)

1364 1 (dm 1JC-F = 246 Hz CF) 1356 (C10) 1348 (C5) 1325 (C2) 1313 (C7) 1310 (C15)

1305(C8) 1297 (C4) 1292 (C3) 1278 (C16) 1274 (C14) 1269 (C11) 1257 (C17) 1255 (C9)

1155 (C12) 937 (C18) 557 (OMe) 283 (Me)


(m 2H H4) 730 (m 2H H3) 726 (m 2H H8) 717 (m 2H H12) 702 (m

2H H11) 696 (m 1H H9) 378 (s 3H OMe) 279 (s 3H Me) 13C1H

NMR (125 MHz CD2Cl2) δ 1892 (C1) 1620 (C13) 1432 (C6) 1348 (C5)

1345 (C10) 1325 (C2) 1319 (C7) 1310 (C3) 1297 (C4) 1257 (C11) 1255

(C9) 1242 (C8) 1162 (C12) 557 (OMe) 283 (Me) 19F and 11B NMR are the same as above


In the glove box a 4 dram vial equipped with a stir bar was charged with a solution of B(C6F5)3

(0379 g 0740 mmol) and either diphenylamine (125 mg 0740 mmol) or N-isopropylaniline

(100 mg 0740 mmol) To the vial the respective alkyne was added over 1 min In the case

where pentane was used as the solvent the reaction was worked up as follows the solvent was

decanted and the product was washed with pentane (3 times 5 mL) to yield the product as a solid In

162

the case where toluene or dichloromethane was used as the as solvent the reaction was worked

up as follows the solvent was removed under reduced pressure and the crude product was

washed with pentane to yield the product as a solid

Synthesis of [Ph2N=C(CH3)Bu][BuCequivCB(C6F5)3] (46) 1-Hexyne (122 mg 148 mmol)

pentane (20 mL) -30 degC to room temperature reaction time 2 h yellow solid (350 mg 414

mmol 56) The reaction also yielded alkenylboranes resulting from 11-carboboration which

were separated from the reaction mixture through the pentane washes during work-up

1H NMR (400 MHz CD2Cl2) δ 768 (m 6H Ph) 738 (m 4H Ph) 282

(m 2H H2) 262 (s 3H Me) 211 (t 3JH-H = 67 Hz 2H H7) 180 (quint

of t 3JH-H = 77 Hz 4JH-H = 28 Hz 2H H3) 141 (m 6H H4 H8 H9) 092

(t 3JH-H = 73 Hz 3H H5) 087 (t 3JH-H = 72 Hz 3H H10) 19F NMR


p-C6F5) -1675 (m 2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ -211

(s equivCB) 13C1H NMR (101 MHz CD2Cl2) δ 1992 (C1) 1482 (dm 1JC-F = 237 Hz CF)

1411 (ipso-Ph) 1407 (ipso-Ph) 1382 (dm 1JC-F = 242 Hz CF) 1363 (dm 1JC-F = 246 Hz

CF) 1319 (Ph) 1315 (Ph) 1314 (Ph) 1236 (Ph) 1234 (Ph) 932 (C6) 389 (C2) 320 (C8)

295 (C3) 248 (Me) 227 (C4) 219 (C9) 199 (C7) 135 (C10) 130 (C5) (CequivCB(C6F5)3 and

ipso-C6F5 were not observed) Anal calcd () for C42H31BF15N C 5966 H 370 N 166

Found 5885 H 366 N 154

Synthesis of [Ph2N=C(CH3)C14H9][C14H9CequivCB(C6F5)3] (47) 9-Ethynylphenanthrene (299

mg 148 mmol) pentane (15 mL) room temperature reaction time 3 h pale yellow solid (602

mg 0555 mmol 75) Crystals suitable for X-ray diffraction were grown from a layered

solution of bromobenzenepentane at -30 ordmC

1H NMR (500 MHz CD2Cl2) δ 859 (dm 3JH-H = 82 Hz 1H ArH) 853 (dm 3JH-H = 82 Hz

1H ArH) 849 (m 2H ArH) 845 (dm 3JH-H = 82 Hz 1H ArH) 776 (dm 3JH-H = 76 Hz 1H ArH) 773 (tm 3JH-H = 76 Hz 1H ArH) 767 (s 1H borateArH) 765 (tm 3JH-H = 82 Hz 1H ArH) 763 (s 1H amineArH) 760 (m 3JH-H = 82 Hz 1H ArH) 757 (m 3H m p-Ph) 755 (m

2H o-Ph) 753 (dm 3JH-H = 76 Hz 1H ArH) 748 (m 2H ArH) 744 (tm 3JH-H = 76 Hz 1H ArH) 737 (tm 3JH-H = 76 Hz 1H ArH) 732 (m 2H ArH) 703 (tt 3JH-H = 70 Hz 4JH-H = 10

Hz 1H ArH) 696 (tm 3JH-H = 70 Hz 2H m-Ph) 691 (dm 3JH-H = 70 Hz 2H o-Ph) 284

163

(Me) 19F NMR (377 MHz CD2Cl2) δ -1324 (m 2F o-C6F5) -1636 (t 3JF-F = 21 Hz 1F p-

C6F5) -1671 (m 2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ -206 (s equivCB) 13C1H NMR

(125 MHz CD2Cl2) δ 1943 (C=N) 1500 (dm 1JC-F = 242 CF) 1444 (ipso-Ph) 1430 (ipso-

Ph) 1400 (dm 1JC-F = 245 CF) 1386 (dm 1JC-F = 250 CF) 1342 (ArC) 1342 (m-Ph) 1337

(p-Ph) 1336 (ArC) 1334 (o-Ph) 1330 (p-Ph) 1326 (ArC) 1325 (ArC) 1321 (ArC) 1320 (m-

Ph) 1319 (ArC) 1317 (ArC) 1315 (ArC) 1313 (ArC) 1310 (ArC) 1307 (ArC) 1306 (ArC)

1303 (ArC) 1301 (ArC) 1298 (ArC) 1297 (ArC) 1286 (ArC) 1284 (ArC) 1284 (ArC) 1280

(ArC) 1272 (ArC) 1261 (o-Ph) 1250 (o-Ph) 1259 (ArC) 1259 (ArC) 1248 (ArC) 1242 (ArC)

1241 (ArC) 937 (CequivCB) 3096 (Me) Anal calcd () for C62H31BF15N C 6859 H 288 N

129 Found C 6812 H 306 N 134

Synthesis of [iPrPhN=C(CH3)C3H5][C3H5CequivCB(C6F5)3] (48) Cyclopropylacetylene (125 μL

148 mmol) dichloromethane (10 mL) and pentane (5 mL) room temperature reaction time 2 h

pale yellow solid (507 mg 651 mmol 88) Crystals suitable for X-ray diffraction were grown

from a layered solution of bromobenzenepentane at -30 ordmC EZ ratio 17

48 1H NMR (400 MHz CD2Cl2) δ 765 (m 3H m p-Ph) 717 (m 2H

o-Ph) 483 (m 3JH-H = 66 Hz 1H iPr) 222 (s 3H CH3) 158 (m 1H

H1) 146 (m 4H H2) 131 (d 3JH-H = 66 Hz 6H iPr) 112 (tt 3JH-H = 81

Hz 3JH-H = 51 Hz 1H H4) 057 - 050 (m 4H H5) 19F NMR (377 MHz

CD2Cl2) δ -1327 (m 2F o-C6F5) -1642 (t 3JF-F = 20 Hz 1F p-C6F5) -

1675 (m 2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ -211(s equivCB)

13C1H NMR (101 MHz CD2Cl2) δ 1937 (N=C) 1486 (dm 1JC-F = 236 Hz CF) 1383 (dm 1JC-F = 243 Hz CF) 1368 (dm 1JC-F = 245 Hz CF) 1356 (ipso-Ph) 1320 (p-Ph) 1313 (m-

Ph) 1266 (o-Ph) 1258 (ipso-C6F5) 958 (C3) 599 (iPr) 218 (C1) 208 (iPr) 161 (CH3) 153

(C2) 84 (C5) 149 (C4) (CequivCB(C6F5)3 was not observed) Anal calcd () for C37H25BF15N C

5702 H 323 N 180 Found 5667 H 330 N 179

Synthesis of E-[iPrPhN=C(CH3)C4H3S][C4H3SCequivCB(C6F5)3] (49) 2-Ethynylthiophene (160

mg 148 mmol) dichloromethane (4 mL) and pentane (10 mL) room temperature reaction time

1 h pale pink solid (498 mg 0577 mmol 78) Crystals suitable for X-ray diffraction were

grown from a layered solution of bromobenzenepentane at -30 ordmC EZ ratio 71

164

49 1H NMR (400 MHz C6D5Br) δ 738 (d 3JH-H = 45 Hz 1H H3)

733 (t 3JH-H = 72 Hz 1H H10) 731 (d 3JH-H = 45 Hz 1H H5) 726 (t 3JH-H = 72 Hz 2H H9) 693 (d 3JH-H = 38 Hz 1H H12) 674 (d 3JH-H =

53 Hz 1H H14) 667 (t 3JH-H = 45 Hz 1H H4) 664 (dd 3JH-H = 53

Hz 3JH-H = 38 Hz 1H H13) 660 (d 3JH-H = 72 Hz 2H H8) 436 (m 3JH-H = 66 Hz 1H H6) 256 (s 3H Me) 081 (d 3JH-H = 66 Hz 6H

iPr) 19F NMR (377 MHz C6D5Br) δ -1312 (m 2F o-C6F5) -1619 (t 3JF-F = 21 Hz 1F p-

C6F5) -1656 (m 2F m-C6F5) 11B NMR (128 MHz C6D5Br) δ -203 (s equivCB) 13C1H NMR

(101 MHz C6D5Br) δ 1724 (C1) 1486 (dm 1JC-F = 240 Hz CF) 1446 (C5) 1438 (C3) 1384

(dm 1JC-F = 246 Hz CF) 1367 (dm 1JC-F = 267 Hz CF) 1346 (C7) 1330 (C2) 1324 (C10)

1312 (C9) 1290 (C12) 1286 (C4) 1272 (C8) 1269 (C13) 1239 (C14) 593 (C6) 214 (Me)

201 (iPr) (C11 C15 ipso-C6F5 and CequivCB(C6F5)3 were not observed) Anal calcd () for

C39H21BF15NS2 C 5425 H 245 N 162 Found 5415 H 259 N 168

Synthesis of (C6F5)3BCequivC(C6H4)C(Me)=NPh2 (410) 14-Diethynylbenzene (934 mg 0740

mmol) dichloromethane (10 mL) -30 degC to room temperature reaction time 2 h orange solid



1H NMR (400 MHz CD2Cl2) δ 760 (m 3H m p-Ph) 735 (m 4H o m-Ph) 729 (m 5H

C6H4 p-Ph) 706 (dm 3JH-H = 77 Hz 2H o-Ph) 277 (s 3H Me) 19F NMR (377 MHz



(C=N) 1482 (dm 1JC-F = 236 Hz CF) 1433 (ipso-Ph) 1425 (ipso-Ph) 1383 (dm 1JC-F = 243

Hz CF) 1365 (dm 1JC-F = 247 Hz CF) 1364 (quaternary C for C6H4) 1322 (C6H4) 1317 (p-

Ph) 1314 (m-Ph) 1311 (p-Ph) 1308 (m-Ph) 1302 (C6H4) 1282 (quaternary C for C6H4)

1255 (o-Ph) 1244 (o-Ph) 1228 (ipso-C6F5) 937 (CequivCB(C6F5)3) 276 (Me) (CequivCB(C6F5)3

was not observed) Elemental analysis for this compound did not pass after repeated attempts

Synthesis of [tBu(Ph)NH2][PhCequivCB(C6F5)3] (411) tert-Butylaniline (111 mg 0741 mmol)

phenylacetylene (757 mg 0741 mmol) pentane (10 mL) reaction time 16 h off-white solid

(560 mg 0733 mmol 99)

165

1H NMR (400 MHz CD2Cl2) δ 751 (tm 3JH-H = 77 Hz 1H H4) 741

(tm 3JH-H = 77 Hz 2H H3) 728 (m 2H H7) 727 (m 2H H6) 725 (m

1H H8) 684 (dm 3JH-H = 77 Hz 2H H2) 677 (br s 2H NH2) 113 (s

9H tBu) 19F NMR (377 MHz CD2Cl2) δ -1329 (m 2F o-C6F5) -1622

(t 3JF-F = 21 Hz 1F p-C6F5) -1661 (m 2F m-C6F5) 11B NMR (128

MHz CD2Cl2) δ -209 (s equivCB) 13C1H NMR (101 MHz CD2Cl2) partial δ 1479 (dm 1JC-F =

236 Hz CF) 1384 (dm 1JC-F = 241 Hz CF) 1366 (dm 1JC-F = 243 Hz CF) 1319 (C7) 1314

(C4) 1310 (C1) 1307 (C3) 1296 (C6) 1283 (C8) 1258 (C5) 1237 (C2) 941 (C9) 654 (tBu)

262 (tBu) Anal calcd () for C36H21BF15N C 5664 H 277 N 183 Found 5608 H 297 N

174

Synthesis of [iPr2NH2][PhCequivCB(C6F5)3] (412) Diisopropylamine (750 mg 0741 mmol)

phenylacetylene (757 mg 0741 mmol) toluene (10 mL) reaction time 4 h white solid (405

mg 566 mmol 76) Crystals suitable for X-ray diffraction were grown from a layered solution

of bromobenzenepentane at -30 ordmC

1H NMR (400 MHz CD2Cl2) δ 727 (tm 3JH-H = 76 Hz 2H m-Ph) 721 (dm 3JH-H = 76 Hz

2H o-Ph) 718 (tm 3JH-H = 76 Hz 1H p-Ph) 505 (m 2H NH2) 332 (m 3JH-H = 64 Hz 2H

iPr) 114 (d 3JH-H = 64 Hz 12H iPr) 19F NMR (377 MHz CD2Cl2) δ -1329 (m 2F o-C6F5)


208 (s equivCB) 13C1H NMR (101 MHz CD2Cl2) partial δ 1317 (m-Ph) 1292 (o-Ph) 1276

(p-Ph) 511 (iPr) 197 (iPr) Anal calcd () for C32H21BF15N C 5373 H 296 N 196 Found

5318 H 304 N 194

4422 Procedures for hydroarylation of phenylacetylene

Compounds 413 and 414 were prepared in a similar fashion thus only one preparation is

detailed In the glove box a 4 dram vial equipped with a stir bar was charged with a solution of

B(C6F5)3 (0379 g 0740 mmol) and the respective amine (0740 mmol) To the vial

phenylacetylene (756 mg 0740 mol) was added over 1 min The solvent was then removed

under reduced pressure and the crude product was washed with pentane to yield the product as a

solid

166

Synthesis of (PhCH2)2NHC6H4C(Ph)=C(H)B(C6F5)3 (413) NN-Dibenzylaniline (202 mg

0740 mmol) dichloromethane (10 mL) -30 degC to room temperature reaction time 1 h yellow

solid (630 mg 0710 mmol 96) Crystals suitable for X-ray diffraction were grown from a

layered solution of bromobenzenepentane at -30 ordmC

1H NMR (400 MHz CD2Cl2) δ 753 (t 3JH-H = 76 Hz 2H m-Ph) 746 (t 3JH-H = 73 Hz 4H benzylm-Ph) 741 (s 1H =CH) 734 (d 3JH-H = 76 Hz 2H o-Ph) 715 (d 3JH-H = 74 Hz 4H benzylo-Ph) 700 (m 3H p-Ph benzylp-Ph) 691 (d 3JH-H = 86 Hz 2H C6H4) 680 (d 3JH-H = 86

Hz 2H C6H4) 617 (br s 1H NH) 484 (dm JH-H = 126 Hz 2H CH2Ph) 472 (dm JH-H = 126

Hz 2H CH2Ph) 19F NMR (377 MHz CD2Cl2) δ -1319 (m 2F o-C6F5) -1644 (t 3JF-F = 19

Hz 1F p-C6F5) -1680 (m 2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ -158 (s equivCB)

13C1H NMR (101 MHz CD2Cl2) partial δ 1521 (=CH) 1387 (ipso-Ph) 1317 (m-Ph) 1316

(benzylipso-Ph) 1302 (benzylo-Ph) 1300 (benzylm-Ph) 1292 (o-Ph) 1291 (C6H4) 1271 (benzylp-

Ph) 1206 (C6H4) 1256 (p-Ph) 647 (CH2Ph) Elemental analysis was not successful after

numerous attempts

Synthesis of iPr(H)N=C14H9C(Ph)=C(H)B(C6F5)3 (414) N-isopropylanthracen-9-amine (170

mg 0740 mmol) dichloromethane (10 mL) room temperature reaction time 5 h bright yellow



1H NMR (500 MHz CD2Cl2) δ 795 (s 1H C=NH) 785 (m 2H m-Ph) 778 (m 2H o-Ph)

773 (d 3JH-H = 83 Hz 1H C14H9) 762 (d 3JH-H = 83 Hz 1H C14H9) 759 (t 3JH-H = 83 Hz

1H C14H9) 758 (m 1H p-Ph) 689 (t 3JH-H = 83 Hz 1H C14H9) 680 (s 1H =CH) 671 (t 3JH-H = 83 Hz 2H C14H9) 603 (d 3JH-H = 83 Hz 2H C14H9) 544 (s 1H CHC(Ph)=CH) 454

(m 1H iPr) 178 (d 3JH-H = 66 Hz 3H iPr) 126 (d 3JH-H = 66 Hz 3H iPr) 19F NMR (377

MHz CD2Cl2) δ -1322 (m 2F o-C6F5) -1645 (t 3JF-F = 20 Hz 1F p-C6F5) -1681 (m 2F m-

C6F5) 11B NMR (128 MHz CD2Cl2) δ -163 (s equivCB) 13C1H NMR (125 MHz CD2Cl2)

partial δ 1707 (C=CH) 1503 (=CH) 1353 (m-Ph) 1308 (o-Ph) 1290 (C14H9) 1284 (p-Ph)

1276 (C14H9) 1274 (C14H9) 1265 (C14H9) 1255 (C14H9) 1224 (C14H9) 599 (CHC(Ph)=CH)

530 (iPr) 233 (iPr) 228 (iPr) Anal calcd () for C43H23BF15N C 6080 H 273 N 165

Found 6059 H 281 N 197

167

4423 Procedures for catalytic intermolecular hydroamination reactions


In the glovebox a 4 dram vial equipped with a stir bar was charged with diphenylamine (125

mg 740 μmol) (p-C6H4F)2NH (152 mg 740 μmol) or N-isopropylaniline (100 mg 740 μmol)

and B(C6F5)3 (38 mg 74 μmol) in toluene (4 mL) The respective alkyne (740 μmol) was added

at a rate of 10 molh via microsyringe (oils) or by weighing into a vial (solids) Total reaction

time was 10 h after which the reaction was worked up outside of the glovebox The solvent was

removed under vacuum and the crude mixture was dissolved in ethyl acetate (5 mL) and passed

through a short (4 cm) silica column previously treated with Et2NH The crude reaction mixtures

consisted of the starting materials (amine and alkyne) and the product The product was purified

by column chromatography using hexaneethyl acetate (61) as eluent

Compounds 426 - 428 were prepared with slight modifications to the procedure above The

reaction vial was cooled to -30 degC then placed in a pre-cooled -30 degC brass-well before addition

of the alkyne via microsyringe or by weighing into a vial The reaction vial was kept in the brass-

well and warmed up to RT before cooling down the reaction vial again and adding the

subsequent aliquot of alkyne Each addition of alkyne was made in a pre-cooled brass-well The

reactions were worked up similar to the procedure above

(415) Yellow solid (187 mg 620 μmol 84) 1H NMR (400 MHz

CD2Cl2) δ 744 (dd 3JH-H = 75 Hz 4JH-H = 18 Hz 1H H5) 721 -713

(m 5H m-C6H5 H3) 712 - 706 (m 4H o-C6H5) 691 (tt 3JH-H = 72 Hz 4JH-H = 11 Hz 2H p-C6H5) 685 (td 3JH-H = 75 Hz 4JH-H = 18 Hz 1H

H4) 679 (dd 3JH-H = 75 Hz 4JH-H = 18 Hz 1H H2) 501 (s 1H =CH2) 490 (s 1H =CH2)

376 (s 3H OCH3) 13C1H NMR (101 MHz CD2Cl2) δ 1577 (C6) 1498 (C=CH2) 1481

(ipso-C6H5) 1312 (C5) 1296 (C3) 1290 (m-C6H5) 1283 (C1) 1248 (o-C6H5) 1227 (p-C6H5)

1205 (C4) 1112 (C2) 1077 (=CH2) 558 (OCH3) HRMS-ESI+ mz [M+H]+ calcd for

C21H20NO 30215449 Found 30215453

168

(416) Off-while solid (146 mg 510 μmol 69) 1H NMR (600 MHz

CD2Cl2) δ 750 -743 (m 1H H5) 724 - 716 (tm 3JH-H = 74 Hz 4H m-

C6H5) 715 - 708 (m 6H o-C6H5 H3 H4) 706 -701 (m 1H H2) 700-

692 (tm 3JH-H = 74 Hz 2H p-C6H5) 484 (s 1H =CH2) 470 (s 1H

=CH2) 252 (s 3H CH3) 13C1H NMR (125 MHz CD2Cl2) δ 1526 (C=CH2) 1476 (ipso-

C6H5) 1390 (C1) 1364 (C6) 1309 (C5 C2) 1291 (m-C6H5) 1281 (C4) 1259 (C3) 1255 (o-

C6H5) 1233 (p-C6H5) 1051 (=CH2) 206 (CH3) HRMS-ESI+ mz [M+H]+ calcd for C21H20N

28615957 Found 28615986

(417) Orange solid (147 mg 460 μmol 62) 1H NMR (400 MHz

CD2Cl2) δ 870 (d 3JH-H = 85 Hz 1H H10) 777 (d 3JH-H = 85 Hz 1H

H7) 771 - 768 (m 2H H2 H4) 752 (tm 3JH-H = 85 Hz 1H H9) 743

(tm 3JH-H = 85 Hz 1H H8) 736 (tm 3JH-H = 85 Hz 1H H3) 722 -

709 (m 8H o m-C6H5) 692 (m 2H p-C6H5) 507 (s 1H =CH2)

494 (s 1H =CH2) 13C1H NMR (101 MHz CD2Cl2) δ 1513 (C=CH2) 1478 (ipso-C6H5)

1371 (C1) 1341 (C6) 1319 (C5) 1292 (m-C6H5) 1288 (C7 C2) 1281 (C4) 1266 (C9) 1260

(C8) 1256 (C10) 1254 (C3) 1253 (o-C6H5) 1229 (p-C6H5) 1067 (=CH2) HRMS-ESI+ mz

[M+H]+ calcd for C24H20N 32215957 Found 32216049

(418) Yellow oil (148 mg 550 μmol 74) 1H NMR (500 MHz

CD2Cl2) δ 757 (dm 3JH-H = 73 Hz 2H H2) 728 - 726 (m 3H H3 H4)

720 (tm 3JH-H = 74 Hz 4H m-C6H5) 709 (dm 3JH-H = 74 Hz 4H o-

C6H5) 695 (tm 3JH-H = 74 Hz 2H p-C6H5) 523 (s 1H =CH2) 486 (s

1H =CH2) 13C1H NMR (125 MHz CD2Cl2) δ 1533 (C=CH2) 1482 (ipso-C6H5) 1394 (C1)

1293 (m-C6H5) 1286 (C3) 1285 (C4) 1276 (C2) 1243 (o-C6H5) 1228 (p-C6H5) 1082

(=CH2) HRMS-ESI+ mz [M+H]+ calcd for C20H18N 2721433 Found 2721443

(419) Orange solid (134 mg 390 μmol 52)1H NMR (500 MHz

CD2Cl2) δ 753 (ddd 3JH-H = 77 Hz 4JH-H = 18 Hz 5JH-H = 04 Hz 1H

H2) 744 (ddd 3JH-H = 77 Hz 4JH-H = 18 Hz 5JH-H = 04 Hz 1H H5)

723 (td 3JH-H = 77 Hz 4JH-H = 18 Hz 1H H3) 720 - 715 (m 8H om-

C6H5) 706 (pseudo td 3JH-H = 77 Hz 4JH-H = 18 Hz 1H H4) 697 (tt 3JH-H = 70 Hz 4JH-H =

16 Hz 2H p-C6H5) 493 (d 2JH-H = 04 Hz 1H =CH2) 483 (d 2JH-H = 04 Hz 1H =CH2)

169

13C1H NMR (125 MHz CD2Cl2) δ 1513 (C=CH2) 1473 (ipso-C6H5) 1399 (C1) 1337 (C5)

1327 (C2) 1296 (C4) 1291 (m-C6H5) 1275 (C3) 1256 (o-C6H5) 1235 (p-C6H5) 1224 (C6)

1059 (=CH2) HRMS-ESI+ mz [M+H]+ calcd for C20H17BrN 35005444 Found 35005379


CD2Cl2) δ 750 (ddm 3JH-H = 78 Hz 4JH-H = 18 Hz 1H H2) 743

(ddm 3JH-H = 78 Hz 4JH-H = 12 Hz 1H H5) 724 (tdm 3JH-H = 78

Hz 4JH-H = 12 Hz 1H H4) 712 (dm 3JH-H = 80 Hz 4H H8) 707

(dm 3JH-H = 78 Hz 1H H3) 690 (tm 3JH-H = 80 Hz 4H H9) 479 (s

1H =CH2) 471 (s 1H =CH2) 19F NMR (377 MHz CD2Cl2) δ -1202 (tt 3JF-H = 88 Hz 4JF-H

= 52 Hz p-C6H4F) 13C1H NMR (125 MHz CD2Cl2) δ 1593 (d 1JC-F = 242 Hz C10) 1518

(C=CH2) 1433 (d 4JCF = 29 Hz C7) 1395 (C1) 1337 (C5) 1328 (C2) 1298 (C3) 1276 (C4)

1272 (d 3JC-F = 79 Hz C8) 1223 (C6) 1159 (d 2JC-F = 22 Hz C9) 1041 (=CH2) HRMS-

ESI+ mz [M+H]+ calcd for C20H15BrF2N 38603559 Found 38603477


CD2Cl2) δ 748 (pseudo td 3JH-H = 77 Hz J = 19 Hz 1H H2) 721

(m 1H H4) 707 - 702 (m 5H H3 H8) 697 (m 1H H5) 691 (m

4H H9) 500 (d 5JF-H = 15 Hz 1H =CH2) 488 (s 1H =CH2) 19F

NMR (377 MHz CD2Cl2) δ -1162 (dm 3JF-H = 119 Hz 1F CF of

C6) -1207 (tm 3JF-H = 97 Hz 2F p-C6H4F) 13C1H NMR (101 MHz CD2Cl2) δ 1605 (d 1JC-F = 249 Hz CF of C6) 1591 (d 1JC-F = 244 Hz C10) 1475 (C=CH2) 1438 (d 4JC-F = 28


1264 (d 3JC-F = 81 Hz C8) 1244 (d 4JC-F = 37 Hz C3) 1162 (d 2JC-F = 22 Hz C5) 1160 (d 2JC-F = 22 Hz C9) 1077 (d 4JC-F = 36 Hz =CH2) HRMS-ESI+ mz [M+H]+ calcd for

C20H15F3N 32611566 Found 32611576


CD2Cl2) δ 718 (dd 3JH-H = 51 4JH-H = 12 Hz 1H H4) 712 (dd 3JH-H

= 36 Hz 4JH-H = 12 Hz 1H H2) 705 - 701 (m 4H H6) 695 - 689

(m 5H H3 H7) 526 (s 1H =CH2) 469 (s 1H =CH2) 19F NMR (377

MHz CD2Cl2) δ -1209 (m 3JF-H = 90 Hz p-C6H4F) 13C1H NMR

(101 MHz CD2Cl2) δ 1589 (d 1JC-F = 241 Hz C8) 1473 (C=CH2) 1442 (d 4JC-F = 26 Hz

170

C5) 1436 (C1) 1276 (C3) 1265 (C2) 1258 (C4) 1257 (d 3JC-F = 80 Hz C6) 1162 (d 2JC-F =

22 Hz C7) 1068 (=CH2) HRMS-ESI+ mz [M+H]+ calcd for C18H14F2NS 31408150 Found

31408200


CD2Cl2) δ 715 (tm 3JH-H = 79 Hz 2H m-C6H5) 712 (dd 3JH-H = 53 Hz 4JH-H = 13 Hz 1H H4) 701 (dd 3JH-H = 35 Hz 4JH-H = 13 Hz 1H H2)

693 (dm 3JH-H = 79 Hz 2H o-C6H5) 685 (m 1H H3) 681 (tm 3JH-H =

79 Hz 1H p-C6H5) 531 (s 1H =CH2) 484 (s 1H =CH2) 426 (m 3JH-H = 66 Hz 1H iPr)

125 (d 3JH-H = 66 Hz 6H iPr) 13C1H NMR (101 MHz CD2Cl2) δ 1466 (ipso-C6H5) 1456

(C1) 1446 (C=CH2) 1296 (m-C6H5) 1274 (C2) 1260 (C3) 1253 (C4) 1208 (o-C6H5) 1206

(p-C6H5) 502 (iPr) 211 (iPr) HRMS-ESI+ mz [M+H]+ calcd for C18H14F2NS 2441154

Found 2441166

(424) Pale yellow solid (206 mg 560 μmol 75) 1H NMR (600

MHz CD2Cl2) δ 881 (dm 3JH-H = 78 Hz 1H H14) 865 (dm 3JH-H =

78 Hz 1H H11) 860 (dd 3JH-H = 78 Hz 4JH-H = 14 Hz 1H H10)

797 (s 1H H2) 787 (dd 3JH-H = 78 Hz 4JH-H = 14 Hz 1H H7)

766-761 (m 3H H9 H12 H13) 757 (pseudo td 3JH-H = 78 Hz 4JH-H

= 14 Hz 1H H8) 723 (m 4H o-C6H5) 715 (t 3JH-H = 73 Hz 4H m-C6H5) 692 (tt 3JH-H =

73 Hz 4JH-H = 12 Hz 2H p-C6H5) 512 (s 1H =CH2) 503 (s 1H =CH2) 13C1H NMR (125

MHz CD2Cl2) δ 1516 (C=CH2) 1476 (ipso-C6H5) 1357 (C1) 1317 (C3) 1309 (C6) 1307

(C5) 1306 (C4) 1294 (C2) 1292 (m-C6H5) 1291 (C7) 1273 (C9) 1271 (C8 C13) 1268 (C12)

1264 (C14) 1255 (o-C6H5) 1235 (p-C6H5) 1232 (C11) 1228 (C10) 1060 (=CH2) HRMS-

ESI+ mz [M+H]+ calcd for C28H22N 37217522 Found 37217485


MHz CD2Cl2) δ 874 (dm 3JH-H = 74 Hz 1H H14) 866 (dm 3JH-H

= 74 Hz 1H H11) 861 (dm 3JH-H = 74 Hz 1H H10) 795 (s 1H

H2) 788 (dm 3JH-H = 74 Hz 1H H7) 767- 762 (m 3H H9 H12

H13) 759 (pseudo td 3JH-H = 74 Hz 4JH-H = 12 Hz 1H H8) 718

(m 4H H16) 686 (m 4H H17) 499 (s 1H =CH2) 495 (s 1H =CH2) 19F NMR (377 MHz

CD2Cl2) δ -1200 (tt 3JF-H = 84 Hz 4JF-H = 42 Hz p-C6H4F) 13C1H NMR (125 MHz

171

CD2Cl2) δ 1592 (d 1JC-F = 240 Hz C18) 1519 (C=CH2) 1437 (d 4JC-F = 26 Hz C15) 1353

(C1) 1316 (C3) 1308 (C6) 1307 (C5) 1306 (C4) 1296 (C2) 1291 (C7) 1274 (C9) 1272 (C8

C12) 1271 (d 3JC-F = 83 Hz C16) 1269 (C13) 1262 (C14) 1233 (C11) 1228 (C10) 1161 (d 2JCF = 219 Hz C17) 1043 (=CH2) HRMS-ESI+ mz [M+H]+ calcd for C28H20F2N 40815638

Found 40815576


CD2Cl2) δ 735 (dm 3JH-H = 77 Hz 1H H2) 727- 723 (m 2H H3

H6) 701 (m 4H H8) 697- 691 (m 5H H4 H9) 516 (s 1H =CH2)

478 (s 1H =CH2) 19F NMR (377 MHz CD2Cl2) δ -1141 (m 1F

CF of C5) -1205 (m 2F p-C6H4F) 13C1H NMR (101 MHz

CD2Cl2) δ 1632 (d 1JC-F = 245 Hz C5) 1592 (d 1JC-F = 244 Hz C10) 1522 (d 4JC-F = 25 Hz

C=CH2) 1442 (d 4JC-F = 28 Hz C7) 1417 (d 3JC-F = 76 Hz C1) 1303 (d 3JC-F = 84 Hz C3)

1261 (d 3JC-F = 81 Hz C8) 1235 (d 4JC-F = 28 Hz C2) 1162 (d 2JC-F = 22 Hz C9) 1154 (d 2JC-F = 21 Hz C4) 1145 (d 2JC-F = 21 Hz C6) 1074 (=CH2) HRMS-ESI+ mz [M+H]+ calcd

for C20H15F3N 32611566 Found 32611485

(427) White solid (154 mg 500 μmol 68) 1H NMR (500 MHz

CD2Cl2) δ 722 (tm 3JH-H = 73 Hz 4H m-C6H5) 710 (m 2H H2) 705

(dm 3JH-H = 73 Hz 4H o-C6H5) 699 (tm 3JH-H = 73 Hz 2H p-C6H5)

670 (tt 3JH-H = 89 Hz 4JH-H = 24 Hz 1H H4) 525 (s 1H =CH2) 490

(s 1H =CH2) 19F NMR (377 MHz CD2Cl2) δ -1107 (t 3JF-H = 81 Hz m-C6H3F2) 13C1H

NMR (125 MHz CD2Cl2) δ 1634 (d 1JC-F = 248 Hz C3) 1515 (t 4JC-F = 28 Hz C=CH2)

1477 (ipso-C6H5) 1435 (d 3JC-F = 92 Hz C1) 1295 (m-C6H5) 1244 (o-C6H5) 1234 (p-

C6H5) 1105 (d 2JC-F = 21 Hz C2) 1093 (s =CH2) 1037 (t 2JC-F = 25 Hz C4) HRMS-ESI+

mz [M+H]+ calcd for C20H16F2N 30812508 Found 30812511


CD2Cl2) δ 783 (ddq 4JH-H = 20 Hz 12 Hz 4JF-H = 07 Hz 1H H6)

774 (ddq 3JH-H = 78 Hz 4JH-H = 12 Hz 6JF-H = 06 Hz 1H H2) 749

(dddq 3JH-H = 78 Hz 4JH-H = 20 Hz 12 Hz 4JF-H = 07 Hz 1H H4)

739 (pseudo tq 3JH-H = 78 Hz 5JF-H = 07 Hz 1H H3) 721 (tm 3JH-H = 78 Hz 4H m-C6H5)

707 (dm 3JH-H = 78 Hz 4H o-C6H5) 697 (tm 3JH-H = 78 Hz 2H p-C6H5) 526 (d 1H 2JH-H

172

= 07 Hz =CH2) 493 (d 2JH-H = 07 Hz =CH2) 19F NMR (377 MHz CD2Cl2) δ -630 (s CF3)

13C1H NMR (125 MHz CD2Cl2) δ 1517 (C=CH2) 1474 (ipso-C6H5) 1400 (C1) 1304 (q 5JC-F = 13 Hz C2) 1304 (q 2JC-F = 32 Hz C5) 1290 (m-C6H5) 1287 (C3) 1247 (q 3JC-F = 38

Hz C4) 1242 (o-C6H5) 1241 (q 1JC-F = 271 Hz CF3) 1239 (q 3JC-F = 38 Hz C6) 1228 (p-

C6H5) 1083 (=CH2) HRMS-ESI+ mz [M+H]+ calcd for C21H17F3N 34013131 Found

34013065

4424 Procedures for tandem hydroamination and hydrogenation reactions

A general procedure is provided for the preparation of compounds 429 and 430 Following the

10 h catalytic hydroamination reaction in the glovebox the reaction mixture was transferred into

an oven-dried Teflon screw cap glass tube The reaction tube was degassed once through a

freeze-pump-thaw cycle on the vacuumH2 line and filled with H2 (4 atm) at -196 ordmC The tube

was placed in an 80 ordmC oil bath for 14 h The solvent was removed under vacuum and the

mixture was dissolved in ethyl acetate (5 mL) and passed through a short (4 cm) silica column

previously treated with Et2NH The crude reaction mixtures consisted of the starting materials

(amine and alkyne) and the product The product was purified by column chromatography using

hexaneethyl acetate (61) as eluent

Alternative hydrogenation procedure using 5 mol Mes2PH(C6F4)BH(C6F5)2

Mes2PH(C6F4)BH(C6F5)2 (28 mg 37 μmol) was added to the reaction mixture before being

transferred into the glass tube The tube was filled with H2 and placed in an 80 ordmC oil bath The

reaction was stopped after 3 h at 80 ordmC and worked up similar to the procedure above


CD2Cl2) δ 728 - 720 (m 2H H2 H5) 708 - 700 (m 2H H3 H4)

692 (m 4H H9) 680 (m 4H H8) 545 (q 3JH-H = 70 Hz C(CH3)H)

138 (d 3JH-H = 70 Hz C(CH3)H) 19F NMR (377 MHz CD2Cl2) δ -

1186 (m 1F F of C6) -1224 (m 2F F of C10) 13C1H NMR (125

MHz CD2Cl2) δ 1610 (d 1JC-F = 247 Hz C6) 1588 (d 1JC-F = 241 Hz C10) 1436 (d 4JC-F =

26 Hz C7) 1310 (d 2JC-F = 131 Hz C1) 1291 (d 2JC-F = 85 Hz C5) 1284 (d 3JC-F = 43 Hz

C2) 1249 (d 3JC-F = 79 Hz C8) 1244 (d 4JC-F = 35 Hz C3) 1159 (d 2JC-F = 22 Hz C9) 1157

173

(d 3JC-F = 22 Hz C4) 517 (C(CH3)H) 197 (C(CH3)H) HRMS-ESI+ mz [M+H]+ calcd for

C20H17F3N 32813131 Found 32813189


CD2Cl2) δ 724 (tm 3JH-H = 78 Hz 4H m-C6H5) 699 (m 4H H2 p-

C6H5) 688 (dm 3JH-H = 78 Hz 4H o-C6H5) 671 (tt 3JF-H = 89 Hz 4JH-H = 24 Hz 1H H4) 524 (d 3JH-H =70 Hz 1H C(CH3)H) 145 (d

3JH-H = 70 Hz 3H C(CH3)H) 19F NMR (377 MHz CD2Cl2) δ -1105 (m F of C3) 13C1H

NMR (125 MHz CD2Cl2) δ 1634 (dd 1JC-F = 248 Hz 3JC-F = 13 Hz C3) 1496 (t 3JC-F = 79

Hz C1) 1472 (ipso-C6H5) 1297 (m-C6H5) 1235 (o-C6H5) 1212 (p-C6H5) 1100 (dd 2JC-F =

20 Hz 4JC-F = 47 Hz C2) 1202 (t 2JC-F = 27 Hz C4) 579 (C(CH3)H) 203 (C(CH3)H)

HRMS-ESI+ mz [M+H]+ calcd for C20H18F2N 31014073 Found 31014081

4425 Procedures for stoichiometric and catalytic intramolecular hydroamination reactions


detailed In the glove box a 25 mL Schlenk flask equipped with a stir bar was charged with a

toluene (5 mL) solution of B(C6F5)3 (0100 g 0190 mmol) and the respective alkynyl aniline

(0190 mmol) The solution was heated for 2 h at 50 degC and the solvent was subsequently

removed under reduced pressure The crude oil was washed with pentane (2 times 5 mL) to yield the

product as a white solid

Synthesis of C6H5N(CH2)3CCH2B(C6F5)3 (431) N-(Pent-4-ynyl)aniline (300 mg 0190

mmol) product (120 mg 0179 mmol 94)

1H NMR (400 MHz CD2Cl2) δ 746 (m 3H m p-Ph) 691 (dm 3JH-H =

86 Hz 2H o-Ph) 416 (t 3JH-H = 78 Hz 2H H3) 333 (br q 2JB-H = 54

Hz 2H CH2B) 311 (t 3JH-H = 78 Hz 2H H1) 215 (quint 3JH-H = 78 Hz

2H H2) 19F NMR (377 MHz CD2Cl2) δ -1325 (m 2F o-C6F5) -1601 (t 3JF-F = 21 Hz 1F p-C6F5) -1655 (m 2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ -134 (s

CH2B) 13C1H NMR (151 MHz CD2Cl2) δ 1942 (C=N) 1476 (dm 1JC-F = 241 Hz CF)

1392 (dm 1JC-F = 243 Hz CF) 1366 (dm 1JC-F = 247 Hz CF) 1348 (ipso-Ph) 1324 (p-Ph)

174

1311 (m-Ph) 1231 (o-Ph) 1189 (ipso-C6F5) 651 (C3) 411 (C1) 185 (CH2B C2) Anal


Synthesis of C6H5N(CH2)4CCH2B(C6F5)3 (432) N-(Hex-5-ynyl)aniline (340 mg 0190

mmol) product (129 mg 0188 mmol 99) Crystals suitable for X-ray diffraction were grown

from a layered solution of bromobenzenepentane at -30 ordmC

1H NMR (600 MHz CD2Cl2) δ 745 (tt 3JH-H = 75 Hz 4JH-H = 22 Hz

1H p-Ph) 740 (tm 3JH-H = 75 Hz 2H m-Ph) 663 (dm 3JH-H = 75 Hz

2H o-Ph) 372 (t 3JH-H = 73 Hz 2H H4) 316 (br q 2JB-H = 63 Hz 2H

CH2B) 275 (t 3JH-H = 73 Hz 2H H1) 197 (m 2H H3) 176 (m 2H

H2) 19F NMR (377 MHz CD2Cl2) δ -1320 (m 2F o-C6F5) -1611 (t 3JF-

F = 20 Hz 1F p-C6F5) -1656 (m 2F m-C6F5) 11B NMR (128 MHz CD2Cl2) δ -130 (s


1420 (ipso-Ph) 1384 (dm 1JC-F = 243 Hz CF) 1366 (dm 1JC-F = 247 Hz CF) 1301 (m p-

Ph) 1226 (ipso-C6F5) 1237 (o-Ph) 574 (C4) 380 (CH2B) 326 (C1) 213 (C3) 175 (C2)

Anal calcd () for C30H15BF15N C 5228 H 221 N 204 Found 5206 H 272 N 177

Synthesis of [2-MeC8H6N(Ph)][HB(C6F5)3] (433) In the glovebox a 25 mL Schlenk flask

equipped with a stir bar was charged with a toluene (5 mL) solution of B(C6F5)3 (0100 g 0190

mmol) and N-(2-ethynylbenzyl)aniline (390 mg 0190 mmol) The solution was heated for 16 h

under H2 (4 atm) at 80 degC The solvent was subsequently removed under reduced pressure The

crude oil was washed with pentane (2 times 5 mL) to yield the product as a white solid (740 mg

0103 mmol 54)

1H NMR (600 MHz CD2Cl2) δ 812 (dm 3JH-H = 79 Hz JH-H = 10

Hz 1H H9) 799 (td 3JH-H = 79 Hz 4JH-H = 10 Hz 1H H8) 786 (dm 3JH-H = 79 Hz 1H H6) 782 (td 3JH-H = 79 Hz 4JH-H = 10 Hz 1H

H7) 773 - 769 (m 3H H2 and H3) 745 (dm 3JH-H = 76 Hz H1) 556

(q JH-H = 26 Hz 2H H4) 353 (br 1H HB) 289 (t JH-H = 26 Hz Me) 19F NMR (564 MHz

CD2Cl2) δ -1341 (br 2F o-C6F5) -1644 (br 1F p-C6F5) -1674 (br 2F m-C6F5) 11B1H

NMR (192 MHz CD2Cl2) δ -252 (s HB) 13C1H NMR (151 MHz CD2Cl2) 1820 (N=C)

1480 (dm 1JC-F = 247 Hz CF) 1437 (C10) 1373 (C7) 1366 (dm 1JC-F = 241 Hz CF) 1362

(dm 1JC-F = 241 Hz CF) 1347 (ipso-Ph) 1337 (C5) 1322 (C3) 1308 (C2) 1306 (C8) 1266

NB(C6F5)3

4

3

2

1

175

(C9) 1247 (C1) 1234 (C6) 657 (C4) 149 (Me) (ipso-C6F5 was not observed) Anal calcd ()



In the glove box a 25 mL Schlenk bomb equipped with a stir bar was charged with a toluene (2

mL) solution of B(C6F5)3 (20 mg 40 μmol) and the alkynyl aniline (039 mmol) The solution

was heated for 16 h under H2 (4 atm) at 80 degC The solvent was subsequently removed under

reduced pressure The crude oil was washed with pentane (2 times 5 mL) and purified by column

chromatography using hexaneethyl acetate (61) as eluent

Synthesis of 2-MeC4H7N(Ph) (434) N-(Pent-4-ynyl)aniline (600 mg 0390 mmol) product

(427 mg 0265 mmol 68)

1H NMR (500 MHz CD2Cl2) δ 718 (t 3JH-H = 78 Hz 2H m-Ph) 660 (tt 3JH-H =

78 Hz 4JH-H = 11 H 1H p-Ph) 657 (d 3JH-H = 78 Hz 2H o-Ph) 286 (m 3JH-H =

61 Hz 1H NCHCH3) 282 (ddd 2JH-H = 88 Hz 3JH-H = 78 Hz 35 Hz 1H H3)

254 (pseudo q 3JH-H = 83 Hz 1H H3) 211 - 162 (m 4H H1 and H2) 099 (d 3JH-H

= 61 Hz 3H Me) 13C1H NMR (151 MHz CD2Cl2) δ 1474 (ipso-Ph) 1289 (m-Ph) 1148

(p-Ph) 1116 (o-Ph) 540 (NCHCH3) 478 (C3) 330 (C1) 265 (C2) 197 (Me) HRMS-

DART+ mz [M+H]+ calcd for C11H15N 16212827 Found 16212755

Synthesis of 2-MeC5H9N(Ph) (435) N-(Hex-5-ynyl)aniline (682 mg 0390 mmol) product

(451 mg 0257 mmol 66)

1H NMR (500 MHz CD2Cl2) δ 723 (t 3JH-H = 81 Hz 2H m-Ph) 693 (d 3JH-H =

81 Hz 2H o-Ph) 680 (tt 3JH-H = 81 Hz 4JH-H = 11 H 1H p-Ph) 394 (m 1H

NCHCH3) 323 (dt 2JH-H = 121 Hz 3JH-H = 44 Hz 1H H4) 297 (dm 2JH-H = 121

Hz 1H H4) 190 - 160 (m 6H H1 H2 H3) 100 (d 3JH-H = 672 3H Me) 13C1H

NMR (151 MHz CD2Cl2) δ 1516 (ipso-Ph) 1288 (m-Ph) 1187 (p-Ph) 1173 (o-

Ph) 512 (NCHCH3) 446 (C4) 317 (C1) 261 (C3) 198 (C2) 134 (Me) HRMS- DART+ mz

[M+H]+ calcd for C12H17NO 17614392 Found 17614338

176

Synthesis of 2-MeC5H9N(p-FC6H4) (436) 4-Fluoro-N-(hex-5-yn-1-yl)aniline (745 mg 0390


1H NMR (400 MHz C6D5Br) δ 652 (t JH-H = 88 Hz 2H m-H of C6H4F) 637 (dd 3JH-H = 88 Hz 4JH-F = 48 Hz 2H o-H of C6H4F) 306 (m 1H NCHCH3) 241 (m

1H H4) 135 (m 1H H1) 121 (m 1H H3) 113 (m 2H H23) 102 (m 1H H2)

101 (m 1H H2) 045 (d 3JH-H = 65 Hz 3H CH3) 19F NMR (377 MHz C6D5Br)

δ -1235 (s 1F C6H4F) 13C1H NMR (100 MHz C6D5Br) δ 1582 (q 1JC-F = 297

Hz p-C6H4F) 1479 (ipso-C6H4F) 1202 (d 3JC-F = 77 Hz o-C of C6H4F) 1150 (d 3JC-F = 227 Hz m-C of C6H4F) 518 (NCHCH3) 470 (C4) 321 (C1) 260 (C3) 203 (C2) 146

(CH3) HRMS- ESI + mz [M+H]+ calcd for C12H16NF 1941340 Found 1941337

Synthesis of 2-MeC5H9N(p-CH3OC6H4) (437) N-(Hex-5-yn-1-yl)-4-methoxyaniline (792 mg

0390 mmol) product (416 mg 0203 mmol 52)

1H NMR (500 MHz C6D5Br) δ 712 (d 3JH-H = 85 Hz 2H m-H of C6H4OCH3)

700 (d 3JH-H = 85 Hz 2H o-H of C6H4OCH3) 374 (s 3H OCH3) 349 (m 1H

NCHCH3) 309 (m 1H H4) 302 (m 1H H4) 194 (m 1H H1) 184 (m 1H H3)

178 (m 1H H2) 176 (m 1H H3) 161 (m 1H H1) 158 (m 1H H2) 106 (d 3JH-

H = 65 Hz 3H CH3) 13C1H NMR (125 MHz C6D5Br) δ 1542 (p-C6H4OCH3)

1457 (ipso-C6H4OCH3) 1221 (m-C of C6H4OCH3) 1139 (o-C of C6H4OCH3) 546

(OCH3) 534 (NCHCH3) 496 (C4) 331 (C1) 264 (C3) 214 (C2) 160 (CH3) HRMS-ESI+

mz [M+H]+ calcd for C13H19NO 2061539 Found 2061539

Synthesis of 2-MeC8H7N(Ph) (438) N-(2-Ethynylbenzyl)aniline (808 mg 0390 mmol)


1H NMR (400 MHz CD2Cl2) δ 778 (d 3JH-H = 77 Hz 1H C6H4) 745 - 737 (m

5H m-Ph C6H4) 707 (t 3JH-H = 77 Hz 1H p-Ph) 703 (d 3JH-H = 77 Hz 2H o-

Ph) 510 (q 3JH-H = 66 Hz 1H NCH(CH3)) 483 (d 2JH-H = 138 Hz 1H CH2)

463 (d 2JH-H = 138 Hz 1H CH2) 154 (d 3JH-H = 66 Hz 3H CH3) 13C1H NMR

(151 MHz CD2Cl2) δ 1435 (ipso-Ph) 1376 (C1) 1343 (C6) 1297 (m-Ph) 1283

177

(C34) 1245 (C2) 1226 (p-Ph) 1222 (C5) 1161 (o-Ph) 641 (NCH(CH3) 563 (CH2) 182

(CH3) HRMS-DART+ mz [M+H]+ calcd for C15H15N 21012827 Found 21012767

4426 Procedures for reactions with ethynylphosphines

Synthesis of trans-Mes2PC(H)=C(H)Mes2PCequivCB(C6F5)3 (439) In the glove box a 4 dram

vial equipped with a stir bar was charged with a CH2Cl2 (10 mL) solution of B(C6F5)3 (379 mg

0740 mmol) and iPrNHPh (100 mg 0740 mmol) To the vial Mes2PCequivCH (440 mg 0148

mmol) was added and the reaction was left at RT for 16 h The solvent was removed under

reduced pressure and the crude product was washed with pentane to yield the product as a pale

yellow solid (717 mg 0651 mmol 88) Crystals suitable for X-ray diffraction were grown

from a layered solution of dichloromethanepentane at -30 ordmC

1H NMR (400 MHz CD2Cl2) δ 771 (td JP-H = 286 Hz 3JH-H = 172 Hz 1H =CH) 698 (d 4JPH = 49 Hz 4H Mes) 689 (d 4JPH = 32 Hz 4H Mes) 574 (ddd 2JP-H = 273 Hz 3JH-H =

172 3JP-H = 44 Hz 1H =CH) 235 (s 6H Mes) 229 (s 6H Mes) 223 (s 12H Mes) 218 (s

12H Mes) 19F NMR (377 MHz CD2Cl2) δ -1329(m 2F o-C6F5) -1616 (t 3JF-F = 21 Hz 1F

p-C6F5) -1663 (m 2F m-C6F5) 31P1H NMR (162 MHz CD2Cl2) δ -115 (br s PMes2) -143

(d JP-P = 82 Hz PMes2) 11B NMR (128 MHz CD2Cl2) δ -211 (CB) 13C1H NMR (101

MHz CD2Cl2) partial δ 1540 (d 1JC-P = 31 Hz Mes) 1470 (d 1JC-F = 248 Hz CF) 1437 (d

JC-P = 28 Hz Mes) 1417 (d JC-P = 150 Hz Mes) 1413 (d JC-P = 113 Hz Mes) 1393 (Mes)

1321 (d 3JC-P = 14 Hz Mes) 1303 (d 3JC-P = 56 Hz Mes) 1260 (d JC-P = 11 Hz Mes) 1178

(dd 2JC-P = 99 Hz 3JC-P = 27 Hz =CH) 1120 (dd 2JC-P = 85 Hz 3JC-P = 121 Hz =CH) 219 (d 3JC-P = 68 Hz Mes) 218 (d 3JC-P = 14 Hz Mes) 201 (d 5JC-P = 18 Hz Mes) 198 (Mes)

Anal calcd () for C58H46BF15P2 C 6329 H 421 Found C 6282 H 411

Synthesis of tBu2PC(H)=C(H)tBu2PCequivCB(C6F5)3 (440) In the glove box a 4 dram vial

equipped with a stir bar was charged with a CH2Cl2 (10 mL) solution of B(C6F5)3 (379 mg 0144

mmol) To the vial tBu2PCequivCH (250 mg 0148 mmol) was added and the reaction was left at

RT for 16 h The solvent was removed under reduced pressure and the crude product was

washed with pentane to yield the product as an off-white solid (580 mg 0570 mmol 77)


dichloromethanepentane at -30 ordmC

178

1H NMR (600 MHz CD2Cl2) δ 777 (ddd 2JP-H = 46 Hz 3JH-H =15 Hz 3JP-H = 36 Hz 1H

=CH) 650 (ddd 2JP-H = 28 Hz 3JP-H = 19 Hz 3JH-H =15 Hz 1H =CH) 144 (d 3JP-H = 17 Hz

18H tBu) 101 (d 3JP-H = 11 Hz 18H tBu) 19F NMR (564 MHz CD2Cl2) δ -1322 (m 2F o-

C6F5) -1618 (t 3JF-F = 20 Hz 1F p-C6F5) -1665 (m 2F m-C6F5) 31P1H NMR (242 MHz

CD2Cl2) δ 215 (PtBu2) 251 (PtBu2) 11B NMR (192 MHz CD2Cl2) -212 (CB) 13C1H

NMR (151 MHz CD2Cl2) partial δ 1620 (dd 1JC-P = 42 Hz 2JC-P = 32 Hz =CH) 1210 (dd 1JC-P = 82 Hz 2JC-P = 21 Hz =CH) 371 (d 1JC-P = 48 Hz tBu) 325 (d 1JC-P = 22 Hz tBu) 292

(d 2JC-P = 14 Hz tBu) 266 (tBu) Anal calcd () for C38H38BF15P2 C 5354 H 449 Found C

5314 H 432

Compounds 441 and 442 were prepared following the same procedure In the glove box a

Schlenk tube equipped with a stir bar was charged with a CH2Cl2 (10 mL) solution of HB(C6F5)2

(100 mg 0289 mmol) and the appropriate alkynyl-substituted pinacolborane (0289 mmol) was

added at once After 5 minutes Ph2PH (538 mg 0289 mmol) was added to the vial The

reaction was left at RT for 16 h The solvent was then removed under reduced pressure and

pentane (5 mL) was added to the crude oil resulting in precipitate The pentane soluble fraction

was separated from the precipitate concentrated and placed in a -30 degC freezer to give the

product as colourless crystals

Synthesis of Bu(H)Ph2PC-C(H)B(C6F5)2Bpin (441) CH3(CH2)3CequivCBpin (606 mg 0289


1H NMR (600 MHz CD2Cl2) δ 766 (m 2H o-Ph) 757 (tm 3JH-H = 77 Hz 1H p-Ph) 747

(tm 3JH-H = 72 Hz 1H p-Ph) 742 (m 2H m-Ph) 736 (m 2H m-Ph) 733 (m 2H o-Ph) 353

(m 1H CHP) 290 (d 2JH-H = 116 Hz 1H CH2CHP) 278 (d 2JH-H = 116 Hz 1H CH2CHP)

148 (m 1H CHB) 133 (m 2H CH2) 118 (m 2H CH2) 102 (s 6H CH3) 098 (s 6H CH3)

078 (t 3JH-H = 72 Hz 3H CH3) 19F NMR (564 MHz CD2Cl2) δ -1292 (m 2F o-C6F5) -

1328 (m 2F o-C6F5) -1665 (m 2F m-C6F5) -1585 (t 3JF-F = 20 Hz 1F p-C6F5) -1605 (t 3JF-F = 20 Hz 1F p-C6F5) -1651 (m 2F m-C6F5) -1653 (m 2F m-C6F5) 31P1H NMR (242

MHz CD2Cl2) δ 322 (br) 11B NMR (192 MHz CD2Cl2) δ 337 (Bpin) -66 (B(C6F5)2)

13C1H NMR (151 MHz CD2Cl2) partial δ 1362 (d 2JC-P = 91 Hz o-Ph) 1318 (d 4JC-P = 29

Hz p-Ph) 1314 (d 2JC-P = 81 Hz o-Ph) 1313 (d 4JC-P = 28 Hz p-Ph) 1285 (d 3JC-P = 95

Hz m-Ph) 1279 (d 3JC-P = 10 Hz m-Ph) 1279 (d 1JC-P = 332 Hz ipso-Ph) 1238 (d 1JC-P =

179

34 Hz ipso-Ph) 824 (C(CH3)2) 346 (d 1JC-P = 37 Hz CHP) 301 (d 2JC-P = 80 Hz CH2CHP)

290 (d 3JC-P = 49 Hz CH2) 246 (BpinCH3) 242 (BpinCH3) 224 (CH2) 158 (CHB) 079

(CH3) Anal calcd () for C36H33B2F10O2P C 5841 H 449 Found 5808 H 437

Synthesis of Ph2PCH2(CH3)C=CHC(H)B(C6F5)2Bpin (442) CH2=C(CH3)CequivCBpin (567

mg 0289 mmol) product (153 mg 0211 mmol 73) Crystals suitable for X-ray diffraction

were grown from pentane at -30 ordmC

1H31P NMR (600 MHz CD2Cl2) δ 764 (tt 3JH-H = 73 Hz 4JH-H = 14 Hz 1H p-Ph) 755 (d 3JH-H = 73 Hz 2H o-Ph) 749 (t 3JH-H = 75 Hz 2H m-Ph) 727 (tt 3JH-H = 75 Hz 4JH-H = 12

Hz 1H p-Ph) 706 (t 3JH-H = 73 Hz 2H m-Ph) 680 (d 3JH-H = 75 Hz 2H o-Ph) 645 (br 1H

=CH) 320 (d 2JH-H = 14 Hz 1H PCH2) 307 (d 2JH-H = 14 Hz 1H PCH2) 190 (s 3H CH3)

149 (br m 1H CHB) 106 (s 6H CH3) 104 (s 6H CH3) 19F NMR (564 MHz CD2Cl2)

partial δ -1254 (br 2F o-C6F5) -1665 (m 2F m-C6F5) (p-C6F5 was not observed) 31P1H

NMR (242 MHz CD2Cl2) δ 63 (br) 11B NMR (192 MHz CD2Cl2) δ 342 (Bpin) -104

(B(C6F5)2) 13C1H NMR (151 MHz CD2Cl2) partial δ 1481 (H3CC=CH) 1359 (=CH) 1329

(m o-Ph) 1323 (d 4JC-P = 39 Hz p-Ph) 1317 (d 2JC-P = 71 Hz o-Ph) 1311 (d 4JC-P = 30

Hz p-Ph) 1300 (d 3JC-P = 94 Hz m-Ph) 1291 (d 1JC-P = 54 Hz ipso-Ph) 1282 (d 3JC-P = 94

Hz m-Ph) 1251 (d 1JC-P = 54 Hz ipso-Ph) 821 (C(CH3)2) 268 (d 1JC-P = 33 Hz CH2P) 256

(d 3JC-P = 53 Hz H3CC=CH) 245 (BpinCH3) 244 (BpinCH3) 178 (br CHB) Anal calcd ()

for C35H29B2F10O2P C 5805 H 404 Found 5776 H 397









Universitaumlt Muumlnster data sets were collected with a Nonius KappaCCD diffractometer

Programs used data collection COLLECT351 data reduction Denzo-SMN352 absorption

180

correction Denzo353 structure solution SHELXS-97354 structure refinement SHELXL-97355

Thermals ellipsoids are shown with 30 probability R-values are given for observed reflections

and wR2 values are given for all reflections







2) and Fo










4433 Platon Squeeze details

During the refinement of structure 413 electron density peaks were located that were believed

to be highly disordered dichloromethane and 12-dichloroethane molecules Attempts made to

model the solvent molecule were not successful The SQUEEZE option in PLATON356 indicated

there was a large solvent cavity 160 A3 in the asymmetric unit In the final cycles of refinement

this contribution (39 electrons) to the electron density was removed from the observed data The

density the F(000) value the molecular weight and the formula are given taking into account the

results obtained with the SQUEEZE option PLATON

181



41 47 48


Formula wt 88546 108572 77939

Crystal system monoclinic triclinic triclinic

Space group P2(1)n P-1 P-1

a(Aring) 91451(8) 120520(8) 99293(9)

b(Aring) 20583(2) 122120(8) 115709(11)

c(Aring) 20738(2) 184965(12) 168258(15)

α(ordm) 9000 103236(4) 75826(4)

β(ordm) 96295(4) 104461(4) 77700(4)

γ(ordm) 9000 104447(4) 65591(4)

V(Aring3) 38800(6) 24264(3) 16930(3)

Z 4 2 2

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1516 1482 1529

Abs coeff μ mm-1 0138 0126 0146


Rint 00444 00308 00308

Data used 8910 11131 5899


R (gt2σ) 00420 00532 00488

wR2 00964 01380 01380

GOF 1018 1028 1026

182


49 410

(+05 C5H12)

413

(+1 C2H4Cl2)

Formula C39H21B1F15N1S2 C425H23B1F15N1 C48H29B1Cl2F15N1

Formula wt 86350 85145 98643


Space group P2(1)c P-1 P2(1)c

a(Aring) 174202(13) 113739(5) 138815(4)

b(Aring) 135941(10) 115489(6) 242842(7)

c(Aring) 174144(13) 158094(7) 146750(4)

α(ordm) 9000 92979(2) 9000

β(ordm) 118149(3) 97298(2) 1108840(10)

γ(ordm) 9000 116865(3) 9000

V(Aring3) 36362(5) 182343(15) 46220(2)

Z 4 2 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1577 1536 1418

Abs coeff μ mm-1 0256 0143 0236


Rint 00299 00352 00437

Data used 6409 8342 8147


R (gt2σ) 00570 00504 00687

wR2 01537 01410 02122

GOF 1045 1021 1092

183


414

(+05 CH2Cl2 +1 C5H12)

432

(+05 C5H12) 439

Formula C485H36B1Cl1F15N1 C325H21B1F15N1 C58H46B1F15P2

Formula wt 96404 72131 110070


Space group C2c P-1 P-1

a(Aring) 309455(12) 80774(6) 117846(13)

b(Aring) 193567(7) 117730(8) 159017(19)

c(Aring) 182668(6) 158569(11) 16349(2)

α(ordm) 9000 79707(3) 108194(4)

β(ordm) 123002(2) 86387(3) 107588(4)

γ(ordm) 9000 87902(3) 104551(4)

V(Aring3) 91764(6) 148021(18) 25646(5)

Z 8 2 2

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1397 1620 1425

Abs coeff μ mm-1 0179 0160 0179


Rint 00476 00352 00284

Data used 8097 6615 9023


R (gt2σ) 00716 00560 00339

wR2 02417 01703 00880

GOF 1047 1096 1019

184

Table 47 ndash Selected crystallographic data for 440 and 442

440 442

Formula C38H38B1F15P2 C35H29B2F10O2P1

Formula wt 85243 72417

Crystal system monoclinic monoclinic

Space group C2c P2(1)n

a(Aring) 329294(17) 114236(2)

b(Aring) 118317(6) 151074(3)

c(Aring) 206088(10) 192749(4)

α(ordm) 9000 9000

β(ordm) 107535(5) 93553(1)

γ(ordm) 9000 9000

V(Aring3) 76563(7) 332009(11)

Z 8 4

Temp (K) 150(2) 223(2)

d(calc) gcm-3 1479 1449



Rint 00316 0055

Data used 8776 6697

Variables 517 456

R (gt2σ) 00365 00672

wR2 01017 01623

GOF 1021 1048

185

Chapter 5 Conclusion

51 Thesis Summary

The results presented in this thesis demonstrate the application of B(C6F5)3 and other

electrophilic boranes in metal-free synthetic methodologies thereby extending FLP reactivity

beyond the commonly reported stoichiometric activation of small molecules These findings

have also provided metal-free and catalytic routes to transformations typically performed using

transition-metal complexes or stoichiometric main group reagents

Initial results presented herein describe the aromatic reduction of N-phenyl amines in the

presence of an equivalent of B(C6F5)3 using H2 to yield the corresponding cyclohexylammonium

derivatives A reaction mechanism based on experimental evidence and theoretical calculations

has been proposed Elaborating the scope of these metal-free aromatic reductions a p-methoxy

substituted aniline was found to undergo tandem hydrogenation and intramolecular cyclization

with B(C6F5)3 presenting a unique route to a 7-azabicyclo[221]heptane derivative Aromatic

hydrogenations were further probed with pyridines quinolines and other N-heterocycles

Findings within this study were in agreement with the mechanism postulated for the arene

reduction of N-phenyl amines Although these reductions require an equimolar combination of

the aromatic amine and borane in certain cases the reactions take up eight equivalents of H2

Continued interest in FLP hydrogenation of aromatic rings was illustrated by subsequent reports

demonstrating borane-catalyzed stereoselective hydrogenation of pyridines by the Du group264

and catalytic hydrogenation of polyaromatic hydrocarbons by the Stephan group263

The second project discussed in this thesis was directly inspired by findings in the synthesis of a

7-azabicyclo[221]heptane derivative from a p-methoxy substituted aniline Detailed

mechanistic studies showed the B(C6F5)3-methoxide bond is labile under specific reaction

conditions These findings were applied to uncover a catalytic approach to the hydrogenation of

ketones and aldehydes yielding alcohols This method uses FLPs derived from B(C6F5)3 and

ether in which the ether is used as the solvent playing a pivotal role in hydrogen-bonding

interaction with the carbonyl substrate The catalysis was further studied in toluene using

B(C6F5)3 in combination with oxygen containing materials such as cyclodextrins or molecular

sieves Application of these materials provides an avenue to H2 activation and hydrogen-bonding

186

interactions necessary to facilitate hydrogenation In the particular case of aryl ketones the use

of molecular sieves promoted reductive deoxygenation of the substrate to give the aromatic

hydrocarbon product Hydrogenation of carbonyl substrates had perennially remained a

challenging problem since the discovery of FLP chemistry The results reported in this thesis

represent the first successful report of catalytic carbonyl hydrogenation using FLPs It should be

noted that the group of Ashley simultaneously reported the hydrogenation of ketones and

aldehydes using 14-dioxaneB(C6F5) as the FLP catalyst260

Lastly interest in expanding FLP catalysis beyond hydrogenations amineborane FLPs were

applied in the hydroamination of terminal alkynes The stoichiometric reaction of aniline

B(C6F5)3 and two equivalents of alkyne gave a series of iminium alkynylborate complexes

prepared through sequential intermolecular hydroamination and deprotonation reactions This

latter reaction results in the formation of the alkynylborate anion thus preventing participation of

B(C6F5)3 in catalysis Adjustment of the protocol by slow addition of the alkyne prevents the

deprotonation pathway thus allowing B(C6F5)3 to catalyze the Markovnikov hydroamination of

alkynes by a variety of secondary aryl amines affording enamines products This metal-free

route was also amenable to subsequent use of the catalyst in hydrogenation catalysis allowing

for the single-pot and stepwise conversion of the enamine products to the corresponding amines

Further expansion of the reactivity led to catalytic intramolecular hydroaminations affording a

one-pot strategy to N-heterocycles A stoichiometric approach to FLP hydrophosphinations was

also described

52 Future Work

While the reactivities presented in this thesis have typically been the purview of precious metals

research efforts motivated by cost toxicity and low abundance have provided alternative

strategies using main group compounds In 1961 the first metal-free catalytic hydrogenation was

reported displaying the reduction of benzophenone however this reaction required high

temperatures of about 200 degC and H2 pressures greater than 100 atm175 Since then dramatic

progress has been made in the advancement of metal-free catalysis Numerous metal-free

systems with particular emphasis on FLPs have been reported to effect the hydrogenation of an

elaborate list of substrates under mild conditions

187

An important direction to progress the chemistry found during this graduate research work would

be to design a borane reagent that will be suitable for the catalytic hydrogenation of N-phenyl

amines and N-heterocycles Such a direction will allow for a more atom-economic

transformation Ultimately the catalysis could be pursued using chiral boranes that may provide

a stereoselective process to cyclohexylamine derivatives (Scheme 51) Generally aromatic

hydrogenation of nitrogen substrates is a challenging transformation for transition-metal systems

due to deactivation of the catalyst by coordination of the substrate357



An interesting and obvious extension of carbonyl hydrogenations presented in Chapter 3 would

certainly be a FLP route to optically active alcohols Although such products were not obtained

when performing the reductions in the presence of chiral heterogeneous Lewis bases the

application of a chiral borane should be investigated The Du group recently presented the use of

chiral boranes in the asymmetric hydrogenation of silyl enol ethers to give chiral alcohol

products after appropriate work-up procedures97

Furthermore the use of cyclodextrins and molecular sieves in catalysis has presented the

possible notion of expanding homogeneous FLP chemistry to surface chemistry by designing

heterogeneous FLP catalysts that could be readily recycled (Scheme 52) Such a system may be

particularly attractive for industrial applicability Solid catalyst supports such as B(C6F5)3 grafted

onto silica have been used by the Scott group as a co-catalyst for the activation of metal

complexes used in olefin polymerization358 Although this system may not be sufficiently Lewis

acidic for carbonyl reductions further exploration and modification of Lewis acid and base

components could potentially lead to such a system

188

Scheme 52 ndash Proposed heterogeneous FLP catalyst for catalytic carbonyl hydrogenations

The final chapter of this thesis outlined the consecutive hydroamination and hydrogenation of

ethynyl fragments catalyzed by B(C6F5)3 The novelty of this reactivity by FLP systems certainly

demands further explorations Catalytic hydroamination using FLPs could be extended to include

olefins and internal alkynes Furthermore the pursuit of an effective chiral borane catalyst may

provide a potential synthetic route to chiral amines of pharmaceutical and industrial interest

189

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ii

Hydrogenation and Hydroamination Reactions Using

Boron-Based Frustrated Lewis Pairs

Tayseer Mahdi

Doctor of Philosophy


2015

Abstract

New main group systems that provide avenues for small molecule activation have been

illustrated using frustrated Lewis pairs (FLPs) ndash combinations of sterically encumbered Lewis

acids and bases which cannot form adducts The research presented herein expands the small

molecule activation and transformation of FLPs using B(C6F5)3

Combination of the aryl amine tBuNHPh and B(C6F5)3 under H2 at room temperature leads to its

heterolytic splitting forming the complex [tBuNH2Ph][HB(C6F5)3] Exposing the salt to elevated

temperatures is found to follow an alternative mechanism resulting in hydrogenation of the N-

bound phenyl ring affording the isolable cyclohexylammonium salt [tBuNH2Cy][HB(C6F5)3]

This finding is extended to include a series of N-phenyl amines in addition to mono- and di-

substituted pyridines quinolines and several other N-heterocycles

The reaction of B(C6F5)3 and H2 with other substrates namely ketones and aldehydes are also

investigated Catalytic hydrogenation of the carbonyl functional group is achieved in an ethereal

solvent to give alcohol products In these cases the borane and ether behave as a FLP to activate

H2 and effect the reduction Similar reductions are also achieved in toluene using B(C6F5)3 in

iii










iv

Acknowledgments



















keeping us in check










v

Table of Contents

Abstract ii

Acknowledgments iv

Table of Contents v

List of Figures xi

List of Schemes xiv

List of Tables xix






12 Catalysis 4







1342 Alkenes 11

1343 Alkynes 11


1345 CO2 and SO2 13



vi




21 Introduction 19





















vii





23 Conclusions 56









31 Introduction 88










viii










33 Conclusions 113















ix




41 Introduction 132



















x





43 Conclusions 157

















52 Future Work 186

References 189

xi

List of Figures



















ppm [HB(C6F5)3]-) 33





xii






tol (c) 42














N(2) pyridine 54




xiii







104







136











xiv

List of Schemes








adduct at 195 K 9











(bottom) FLPs 15


borohydride FLP 16

xv


















= C6F5 221a and X = H 221b) 41





xvi






alcohols 90





hydrogenation 93












xvii





alkenylboranes 134




136





with [(Et2O)2H][B(C6F5)4] 141







alkynes 147


429 and 430 148

xviii













Ph2PH 155





187


xix

List of Tables














106





138


xx







xxi



α alpha


atm atmosphere

β beta


br broad


Bu butyl

C Celsius

ca circa

calcd calculated

CD cyclodextrin


C6H5Br bromobenzene



Cy cyclohexyl

δ chemical shift

xxii

deg degrees

d doublet

Da Dalton








eq equivalent(s)


Et ethyl

Et2O diethyl ether


γ gamma


g gram


GOF goodness of fit

xxiii

h hour





Hz Hertz



K Kelvin

kcal kilocalories

m meta

m multiplet


Me methyl


MHz megahertz

μL microliter

μmol micromole

mg milligram

min minute

xxiv

mL milliliter

mmol millimole


MS molecular sieves

nPr n-propyl





o ortho

π pi

p para



Ph phenyl

Ph2O diphenyl ether



q quartet

quint quintet

xxv


RT room temperature

σ sigma

s singlet

t triplet

tBu tert-butyl

THF tetrahydrofuran


TMS trimethylsilyl


tol toluene

wt weight

1














chemicals6-8















2






























3








rhombohedral36







industries35-36

112 Boron chemistry















4



















12 Catalysis



5


















131 Early discovery












6





















to boron73





7






under vacuum79-80













8



















9


adduct at 195 K














10










12)105









discussed







11




1342 Alkenes










1343 Alkynes








12

















13


(Scheme 110 right)



1345 CO2 and SO2










111 c)

14

Mes2P B(C6F5)2

EO2Mes2P B(C6F5)2

E O

O

R R

gt -20 degC- CO2

tBu3P B(C6F5)3EO2

80 degC- CO2

PB(C6F5)3E

O

O

tBu3


O

O

AlX3

CO2

b)

a)

c)
















15


(bottom) FLPs

















16

B(C6F5)2R2P

FF

F F

H

H

O

HPhB(C6F5)2R2P

FF

F F

H O

Ph

R = tBu Mes


borohydride FLP
















17



14 Scope of Thesis













reactions







18



















101002anie201503087





19



21 Introduction

211 Hydrogenation




















20





















RhPh3P

Ph3P Cl

PPh3

(a) (b) (c)

(d)

21






















(a) (b)

22


























23













HB(C6F5)2247









24























25






















26

















27







(Figure 25)



12 h

9 h

6 h

3 h

15 h

05 h

$

HB HA

28







(Figure 26)
















29




30



























the borane



31


























32


















33



ppm [HB(C6F5)3]-)
















45 degC

75 degC

95 degC

65 degC

115 degC

55 degC

85 degC

105 degC

34
















21

23

35





computations














36















37


















38










interaction121





















39















in Figure 213

40

HB(C6F5)3

NH

OCH3

B(C6F5)3

Ph

+ CH3OH

NH2

OCH3

Ph

NH2Ph

HB(C6F5)3

NHPh

OCH3

220

212

H2

B(C6F5)3

H2













41






(Scheme 212)


= C6F5 221a and X = H 221b)






42



tol (c)













a)

b)

c)

43

















44














acetonitrile)261









45

NH2

R

OCH3

110 oC

NHR

OCH3

NHR

OCH3

(F5C6)3B

+ H2

B(C6F5)3

H2

HB(C6F5)3

- H2HN

R

CH3OB(C6F5)3

+ H2

HB(C6F5)3

HNR

- CH3OH





















46










redelivery262







47














48













49

















explored


50
















a) b) c)

51








52






B(C6F5)3












53


























54



N(2) pyridine










NN NN

B

B(C6F5)3

(C6F5)3B H

- C6F5H H2

235

(C6F5)2





55






























56

23 Conclusions








rings





pyridines264
















57



























capabilities




58







0186 mmol 95)





















5071 H 258 N 211 Found C 5027 H 287 N 219

59



















252








as a white powder

60
























N 209




61








219












386 N 212










62


359 N 214










C 5014 H 348 N 209











4945 H 329 N 230





63







5011 H 350 N 216











5087 H 399 N 212











64



395 N 187













5358 H 323 N 195 Found C 5374 H 300 N 189









228 Found C 4686 H 247 N 232



65









4973 H 333 N 221






















66











299 N 208 Found C 4804 H 307 N 210














270 N 209 Found C 4793 H 282 N 203




67































68















610 μmol 89)









B(C6F5)4)




69









C6D5Br) δ -238 (d 1JB-H = 78 Hz BH)



















70
























solid





71

















N 223 Found C 4764 H 290 N 222




4660 H 247 N 211






72








(Et)






















73






























74































75




5026 H 330 N 209













N 198 Found C 5214 H 358 N 196











76













observed

















77


H 325 N 347 Found C 5611 H 313 N 321




















526 (CH2CHN) 308 (CH2) 245 (CH2) 229 (CH2) 188 (CH2)






Found C 5347 H 291 N 209

78


crystals)












(PiperidineCH2)













SRSRSR diastereomer



79




























2) and Fo




80







81



24 24rsquo 25


Formula wt 65526 64719 69532



a(Aring) 97241(8) 116228(4) 126342(6)

b(Aring) 147348(12) 181284(7) 181939(8)

c(Aring) 188022(15) 236578(9) 128612(6)

α(ordm) 9000 9000 9000

β(ordm) 98826(4) 9000 90269(2)

γ(ordm) 9000 9000 9000

V(Aring3) 26621(4) 49848(3) 29563(2)

Z 4 8 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1635 1725 1562

Abs coeff μ mm-1 0169 0179 0157


Rint 00336 00297 00369

Data used 4685 8773 5207


R (gt2σ) 00361 00315 00352

wR2 00898 00758 00947

GOF 1007 1021 1024

82


216a 218 219


Formula wt 67325 67123 71533



a(Aring) 97677(6) 104368(7) 18886(4)

b(Aring) 147079(11) 93382(7) 16050(3)

c(Aring) 190576(14) 273881(18) 19128(4)

α(ordm) 9000 9000 9000

β(ordm) 98934(2) 96910(3) 9000

γ(ordm) 9000 9000 9000

V(Aring3) 27046(3) 26499(3) 5798(2)

Z 4 4 8

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1653 1683 16388

Abs coeff μ mm-1 0174 0177 0163


Rint 00432 00404 00662

Data used 6164 4676 6654


R (gt2σ) 00522 00496 00687

wR2 01387 01462 01912

GOF 1032 1041 10743

83


220 222 (+05 CH2Cl2) 224 (+05 CH2Cl2)


Formula wt 74737 72573 79380



a(Aring) 173531(15) 17750(5) 109902(9)

b(Aring) 161365(15) 16032(4) 151213(11)

c(Aring) 227522(17) 20783(6) 194765(15)

α(ordm) 9000 9000 90

β(ordm) 9000 96910(3) 92062(3)

γ(ordm) 9000 9000 90

V(Aring3) 63710(9) 5914(3) 32346(4)

Z 8 8 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 15582 16278 1630

Abs coeff μ mm-1 0154 0250 0235


Rint 00406 01159 00306

Data used 7321 5198 5688


R (gt2σ) 00413 00811 00495

wR2 01112 02505 01363

GOF 10647 10628 0936

84


225 227 (+1 C5H12) 228


Formula wt 62721 141861 66727



a(Aring) 101339(5) 137416(4) 95967(15)

b(Aring) 112923(6) 119983(4) 108364(15)

c(Aring) 118209(6) 191036(7) 14143(2)

α(ordm) 98563(2) 9000 75929(5)

β(ordm) 109751(2) 109317(2) 80009(6)

γ(ordm) 94983(2) 9000 76629(5)

V(Aring3) 124520(11) 297240(17) 13772(4)

Z 2 2 2

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1673 1585 1609

Abs coeff μ mm-1 0176 0158 0235


Rint 00211 00246 00351

Data used 4357 5230 4743


R (gt2σ) 00371 00324 00546

wR2 00964 00816 01728

GOF 1044 1014 1028

85


229 (+05 C6H5Br) 230 231a


Formula wt 80784 66727 70733



a(Aring) 201550(11) 97752(4) 112914(4)

b(Aring) 133628(11) 120580(4) 183705(7)

c(Aring) 266328(18) 121120(5) 145648(5)

α(ordm) 9000 102296(2) 9000

β(ordm) 111905(6) 100079(2) 90480(2)

γ(ordm) 9000 90901(2) 9000

V(Aring3) 66551(8) 137127(9) 302105(19)

Z 8 2 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1613 1616 1555

Abs coeff μ mm-1 0749 0165 0155


Rint 00530 00245 00383

Data used 7644 4841 7630


R (gt2σ) 00651 00362 00778

wR2 01802 00971 02335

GOF 1037 1036 1007

86


231b (+05 C6H14) 233 234a (+1 CH2Cl2)


Formula wt 74840 80642 78621



a(Aring) 107250(6) 99895(4) 181314(6)

b(Aring) 112916(7) 115666(5) 135137(5)

c(Aring) 136756(8) 155410(6) 253612(9)

α(ordm) 70523(2) 9000 9000

β(ordm) 88868(2) 105054(2) 92594(2)

γ(ordm) 86934(2) 9000 9000

V(Aring3) 155914(16) 173405(12) 62077(4)

Z 2 2 8

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1594 1544 1677

Abs coeff μ mm-1 0155 0147 0327


Rint 00233 00381 00512

Data used 5479 8395 7383


R (gt2σ) 00371 00400 00816

wR2 01066 00893 02554

GOF 0926 1011 1024

87


234b 235 (+1 C4H8O +1 CH2Cl2)


Formula wt 70128 120323



a(Aring) 100455(5) 113115(7)

b(Aring) 118185(5) 117849(8)

c(Aring) 245940(11) 188035(12)

α(ordm) 9000 83850(3)

β(ordm) 96724(2) 88364(3)

γ(ordm) 9000 69766(3)

V(Aring3) 28998(2) 23383(3)

Z 4 2

Temp (K) 150(2) 150(2)

d(calc) gcm-3 1606 1709



Rint 00342 00265

Data used 5101 8235

Variables 433 712

R (gt2σ) 00438 00473

wR2 01153 01198

GOF 1012 1015

88



31 Introduction


























89



















(Scheme 32 b)275

90










33)277


alcohols



91

















molecular sieves

92
























93


hydrogenation





















94
















$ $ 12

11

10

9

8

7

6

5

4

3

2

1

95


















96




1 n-C3H7 n-C3H7 gt99 (91) gt99 70 52

2 Me iPr gt99 (76) gt99 44 42

3 Me CH2tBu gt99 gt99 (90) 22 14

4 Me n-C5H11 93 (85) 50 (43) 58 41

5 Me CH2Cl gt99 (85) gt99 91 82

6 Me Cy 77 - - -


8 Et n-C4H9 gt99 (87) 95 44 38

9 Et CH2iPr 40 47 - -



12 Me n-CH2CH2Ph gt99 (84) 69 58 24




16 -(CH2)5- 53 41 - -

17 -(2-iPr-5-Me)C5H8- gt99 (88) 89 47 45

18 Cy H 32 - - -





97





















98












mechanism






99

























100





















101










1 n-C3H7 n-C3H7 92

2 Me iPr 57

3 Me CH2Cl gt99

4 Me 2-butyl 53

5 Et iPr gt99

6 Et CH2iPr 40

7 Me Cy 18

8 Me Ph 20

9 Ph Ph 20

10 Et CH2Ph 25

11 Me n-CH2CH2Ph 25

12 -(CH2)5- 28

13 -(CH2)3CH=CH- 0

14 -(2-iPr-5-Me)C5H8- 62


102









R R1

OH

H

B(C6F5)3

R R1

O

+

B(C6F5)3

R R1

O NEt4

HB(C6F5)3

NEt4

B(C6F5)3

B(C6F5)3

R R1

O

05 H2

05 H2















103




























104



















a) b)

a)

b)

105










ca 70 ppm












106



1 Me iPr gt99 79 77 62 81 gt99

2 Me 2-butyl gt99 74 72 46 75 gt99

3 Me CH2tBu gt99 52 41 40 53 gt99


5 Me Cy gt99 81 62 31 64 gt99

6 Me n-C5H11 gt99 63 56 36 73 gt99

7 Et iPr gt99 75 75 69 80 gt99

8 Et n-C4H9 95 93 95 58 gt99 93

9 n-C3H7 n-C3H7 gt99 - - - - 92

10a Me Ph 30 13 15 10 27 trace

11 CH2CH2Cl Ph 54 - - - - 50

12 CF3 Ph 20 - - - - 20

13 Me o-CF3C6H4 trace - - - - 25

14 Me p-MeSO2C6H4 60 - - - - 97


16 Me CH2(o-FC6H4) 75 70 69 66 34 gt99

17 Me CH2(p-FC6H4) gt99 49 31 55 48 gt99


19 Et CH2Ph gt68 20 31 28 46 gt99

20 -(CH2)5- gt99 72 65 68 90 gt99


22 -(2-iPr-5-Me)C5H8- gt99 70 60 60 80 gt99

23 Cy H 10 - - - - 44

24 Ph2CH H 47 - - - - 86

25 PhCH(Me) H 20 - - - - 35


107












activity















108

















1 H Me CH2 92

2 CF3 Me CH2 95


cis 4

4 H iPr C(Me)2 75

109
















catalytically



1 H Ph 81

2 CH3O Ph 85

3 Br Ph 67

4 tBu Ph gt99

5 CH3 p-CH3C6H4 75

6 CF3 Ph 10

7 H o-CH3C6H4 20

110












and MS








111


















112












approaches62



0 mol

5 mol

10 mol

50 mol


113







in 17 - 25 yield259











33 Conclusions










114































115






protocol105






















116














observed















117































118










(80 eq)




















119


















0320 mmol 92)




247 (d 1JB-H = 91 Hz BH)









120



material ketone











GC-MS
















121






















alcohol products







122



= 731 [M-CH3] 551 [M-CH5O]













CH3] 790 [M-CH3]





1101 [M- H2O] 831 [M-C2H5O]






123


C2H5] 591 [M-C3H7]






691 [M-C2H7O] 590 [M-C4H9]






CH2iPr]





770 [M-C2H5O]







591[M-C7H7]



124





[M-C3H7O]























CH2F3O]

125




4029 min mz = 1001 [M] 821 [M-H2O]








951 [M-C3H9O] 811 [M-C4H12O]










561 [M-C2H6O] 450 [C2H5O]




126











C2H4Cl]






C6H4CF3) 1315 (C3) 1314 (C1) 1294 (C4) 1264 (C2) 1244 (C5) 1240 (CF3) 653


1720 [M-H2O] 1450 [M-C2H5O]










1811 [M-OH] 1671 [M-CH3O]

127





1211 [M-CH3] 1051 [M-CH3O]



alcohol products













1451 [M-C2H3] 1031 [M-CF3]







128














alcohol products











1211 [M-C6H5] 911 [M-C7H7O] 771 [M-C8H9O]





129


mz = 2480 [M+2] 2460 [M] 1671 [M-Br] 911 [M-C6H4Br]







CH3) 911 [C7H7]





[M] 1811 [M-CH3) 1661 [M-2(CH3)] 1051 [M-C7H7] 911 [M- C8H9]







1591 [M-C6H5] 911 [C7H7]


776 (m 2H o-Ph) 767 - 761 (m 3H m p-Ph) 759 - 754 (m 4H




GC-MS 12844 min mz = 1821 [M] 1671 [M-CH3]

130





15761 min mz = 1941 [M] 1791 [M-CH3] 1651 [M-C2H5]















2) and Fo










131



31 (+05 C6D5Br)


Formula wt 100893


Space group P2(1)c

a(Aring) 127865(6)

b(Aring) 199241(9)

c(Aring) 170110(7)

α(ordm) 9000

β(ordm) 1067440(10)

γ(ordm) 9000

V(Aring3) 41500(3)

Z 4

Temp (K) 150(2)

d(calc) gcm-3 1607



Rint 00368

Data used 9534

Variables 596

R (gt2σ) 00458

wR2 01145

GOF 1020

132



41 Introduction

411 Hydroamination






imines and enamines















133






















134










alkenylboranes

135




















136
















137















138


139
















(a) (b)

140



















141





















142



















143

















(Scheme 412)

(a) (b)

144


























145





146



(Table 42)


















products341






147


alkynes

















148


429 and 430






was not successful











149

















150





yield (Scheme 416)




















151


yield (Scheme 417)







1 H 0 68 434

2 H 1 66 435

3 F 1 72 436

4 CH3O 1 52 437








152







574 ppm (Figure 47)


the zwitterion 439








1H

1H31P

153




















(a) (b)

154




















155



Ph2PH









156









allenes147











157

43 Conclusions


























column prior to use




158

















experiments












159



product as a solid




-30 ordmC








1312 (p-Ph) 1310 (C7) 1307 (m-Ph) 1298 (Ph) 1293 (Ph) 1277 (C8) 1257 (C9) 1254 (o-





EZ ratio 71








CF) 1346 (C2) 1339 (C5) 1319 (C10) 1318 (C7) 1311 (C12) 1310 (C4) 1303 (C9) 1278

(C13) 1274 (C11) 1258 (C14) 1253 (C3 C8) 937 (C15) 619 (C6) 288 (Me) 208 (iPr)

160


296 N 165 Found 6037 H 317 N 173



EZ ratio 71









CD2Cl2) δ 1916 (C1) 1341 (C5) 1323 (C13) 1315 (C15) 1313 (C4) 1307 (C12) 1282 (C16)

1262 (C17) 1257 (C3) 1254 (C11) 699 (C6) 320 (C7) 291 (Me) 249 (C8) 244 (C9) (C2


C 6197 H 328 N 157 Found 6158 H 354 N 153












(C2) 1317 (C11 C14) 1311 (C9) 1309 (C13 C15) 1304 (C4 C10) 1296 (C8) 1294 (C16) 1278

B(C6F5)3

N1

2

3

45

7

8

9

10

14

1516

17

18

6

11

12

13

B(C6F5)3

N1

2

3

45

7

8 9

10

11 12

13

14

1617

1815

6

19

161



156 Found 6259 H 296 N 171




6106 H 262 N 142 EZ ratio 11


(m 2H H3) 730 (m 2H H4) 726 (m 2H H8) 717 (m 2H H15) 707







1364 1 (dm 1JC-F = 246 Hz CF) 1356 (C10) 1348 (C5) 1325 (C2) 1313 (C7) 1310 (C15)

1305(C8) 1297 (C4) 1292 (C3) 1278 (C16) 1274 (C14) 1269 (C11) 1257 (C17) 1255 (C9)

1155 (C12) 937 (C18) 557 (OMe) 283 (Me)


(m 2H H4) 730 (m 2H H3) 726 (m 2H H8) 717 (m 2H H12) 702 (m



1345 (C10) 1325 (C2) 1319 (C7) 1310 (C3) 1297 (C4) 1257 (C11) 1255








162



















Found 5885 H 366 N 154









163










129 Found C 6812 H 306 N 134














5702 H 323 N 180 Found 5667 H 330 N 179





164









1312 (C9) 1290 (C12) 1286 (C4) 1272 (C8) 1269 (C13) 1239 (C14) 593 (C6) 214 (Me)


















(560 mg 0733 mmol 99)

165








(C4) 1310 (C1) 1307 (C3) 1296 (C6) 1283 (C8) 1258 (C5) 1237 (C2) 941 (C9) 654 (tBu)


174











5318 H 304 N 194







solid

166












numerous attempts














Found 6059 H 281 N 197

167

























C21H20NO 30215449 Found 30215453

168



C6H5) 715 - 708 (m 6H o-C6H5 H3 H4) 706 -701 (m 1H H2) 700-



C6H5) 1390 (C1) 1364 (C6) 1309 (C5 C2) 1291 (m-C6H5) 1281 (C4) 1259 (C3) 1255 (o-


28615957 Found 28615986



H7) 771 - 768 (m 2H H2 H4) 752 (tm 3JH-H = 85 Hz 1H H9) 743




1371 (C1) 1341 (C6) 1319 (C5) 1292 (m-C6H5) 1288 (C7 C2) 1281 (C4) 1266 (C9) 1260








1293 (m-C6H5) 1286 (C3) 1285 (C4) 1276 (C2) 1243 (o-C6H5) 1228 (p-C6H5) 1082








169


1327 (C2) 1296 (C4) 1291 (m-C6H5) 1275 (C3) 1256 (o-C6H5) 1235 (p-C6H5) 1224 (C6)














(m 1H H4) 707 - 702 (m 5H H3 H8) 697 (m 1H H5) 691 (m






C20H15F3N 32611566 Found 32611576



= 36 Hz 4JH-H = 12 Hz 1H H2) 705 - 701 (m 4H H6) 695 - 689




170



31408200






(C1) 1446 (C=CH2) 1296 (m-C6H5) 1274 (C2) 1260 (C3) 1253 (C4) 1208 (o-C6H5) 1206


Found 2441166









(C5) 1306 (C4) 1294 (C2) 1292 (m-C6H5) 1291 (C7) 1273 (C9) 1271 (C8 C13) 1268 (C12)






H2) 788 (dm 3JH-H = 74 Hz 1H H7) 767- 762 (m 3H H9 H12




171


(C1) 1316 (C3) 1308 (C6) 1307 (C5) 1306 (C4) 1296 (C2) 1291 (C7) 1274 (C9) 1272 (C8


Found 40815576



H6) 701 (m 4H H8) 697- 691 (m 5H H4 H9) 516 (s 1H =CH2)






for C20H15F3N 32611566 Found 32611485
















172





34013065
















CD2Cl2) δ 728 - 720 (m 2H H2 H5) 708 - 700 (m 2H H3 H4)







173


C20H17F3N 32813131 Found 32813189
























174





















0103 mmol 54)









NB(C6F5)3

4

3

2

1

175










(427 mg 0265 mmol 68)









(451 mg 0257 mmol 66)








176




1H H4) 135 (m 1H H1) 121 (m 1H H3) 113 (m 2H H23) 102 (m 1H H2)






















177




























178








5314 H 432





















179





























180










2) and Fo


















181



41 47 48


Formula wt 88546 108572 77939



a(Aring) 91451(8) 120520(8) 99293(9)

b(Aring) 20583(2) 122120(8) 115709(11)

c(Aring) 20738(2) 184965(12) 168258(15)

α(ordm) 9000 103236(4) 75826(4)

β(ordm) 96295(4) 104461(4) 77700(4)

γ(ordm) 9000 104447(4) 65591(4)

V(Aring3) 38800(6) 24264(3) 16930(3)

Z 4 2 2

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1516 1482 1529

Abs coeff μ mm-1 0138 0126 0146


Rint 00444 00308 00308

Data used 8910 11131 5899


R (gt2σ) 00420 00532 00488

wR2 00964 01380 01380

GOF 1018 1028 1026

182


49 410

(+05 C5H12)

413

(+1 C2H4Cl2)


Formula wt 86350 85145 98643



a(Aring) 174202(13) 113739(5) 138815(4)

b(Aring) 135941(10) 115489(6) 242842(7)

c(Aring) 174144(13) 158094(7) 146750(4)

α(ordm) 9000 92979(2) 9000

β(ordm) 118149(3) 97298(2) 1108840(10)

γ(ordm) 9000 116865(3) 9000

V(Aring3) 36362(5) 182343(15) 46220(2)

Z 4 2 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1577 1536 1418

Abs coeff μ mm-1 0256 0143 0236


Rint 00299 00352 00437

Data used 6409 8342 8147


R (gt2σ) 00570 00504 00687

wR2 01537 01410 02122

GOF 1045 1021 1092

183


414

(+05 CH2Cl2 +1 C5H12)

432

(+05 C5H12) 439


Formula wt 96404 72131 110070



a(Aring) 309455(12) 80774(6) 117846(13)

b(Aring) 193567(7) 117730(8) 159017(19)

c(Aring) 182668(6) 158569(11) 16349(2)

α(ordm) 9000 79707(3) 108194(4)

β(ordm) 123002(2) 86387(3) 107588(4)

γ(ordm) 9000 87902(3) 104551(4)

V(Aring3) 91764(6) 148021(18) 25646(5)

Z 8 2 2

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1397 1620 1425

Abs coeff μ mm-1 0179 0160 0179


Rint 00476 00352 00284

Data used 8097 6615 9023


R (gt2σ) 00716 00560 00339

wR2 02417 01703 00880

GOF 1047 1096 1019

184


440 442





a(Aring) 329294(17) 114236(2)

b(Aring) 118317(6) 151074(3)

c(Aring) 206088(10) 192749(4)

α(ordm) 9000 9000

β(ordm) 107535(5) 93553(1)

γ(ordm) 9000 9000

V(Aring3) 76563(7) 332009(11)

Z 8 4

Temp (K) 150(2) 223(2)

d(calc) gcm-3 1479 1449



Rint 00316 0055

Data used 8776 6697

Variables 517 456

R (gt2σ) 00365 00672

wR2 01017 01623

GOF 1021 1048

185


51 Thesis Summary




























186




















also described

52 Future Work









187
























188







189

References




2008 1 636-639




Am Chem Soc 1955 77 1708-1710









15 Monnin E Science 2001 291 112-114





190





2011 333 863-866





27 Power P P Nature 2010 463 171-177













191








Commun 2000 3 530-533








Catal A Chem 1996 111 67-79








192



















2010 132 9604-9606



2009 1534-1541


193


















Int Ed 2008 47 7543-7546




194




Chem Int Ed 2012 51 10164-10168


2013 5 718-723




Synth Catal 2011 353 2093-2110















195




















196


2015 DOI 101039C4CY01716A








Chem Soc 2009 131 12280-12289


Chem Soc 2009 131 12280-12289












197












2013 135 9326-9329


2014 136 10708-10717




2011 6771-6777







198


Trans 2012 41 4310-4312




1998 17 1369-1377


















199






Chem Soc 2006 128 8724-8725










212 Davey S Nat Chem 2012 4 337-337










200







2012 51 4452-4455


















201










Chem Int Ed 2010 49 6559-6563












202





Chem 1996 61 3849-3862




















Chem Soc 2012 134 10843-10851

203



















Chem 1978 43 374-375






204


305 Trost B Science 1991 254 1471-1477





















Commun 2007 0 278-279

205








Commun 2014 50 1980-1982


Chem Soc 2013 136 777-782













206














iii










iv

Acknowledgments



















keeping us in check










v

Table of Contents

Abstract ii

Acknowledgments iv

Table of Contents v

List of Figures xi

List of Schemes xiv

List of Tables xix






12 Catalysis 4







1342 Alkenes 11

1343 Alkynes 11


1345 CO2 and SO2 13



vi




21 Introduction 19





















vii





23 Conclusions 56









31 Introduction 88










viii










33 Conclusions 113















ix




41 Introduction 132



















x





43 Conclusions 157

















52 Future Work 186

References 189

xi

List of Figures



















ppm [HB(C6F5)3]-) 33





xii






tol (c) 42














N(2) pyridine 54




xiii







104







136











xiv

List of Schemes








adduct at 195 K 9











(bottom) FLPs 15


borohydride FLP 16

xv


















= C6F5 221a and X = H 221b) 41





xvi






alcohols 90





hydrogenation 93












xvii





alkenylboranes 134




136





with [(Et2O)2H][B(C6F5)4] 141







alkynes 147


429 and 430 148

xviii













Ph2PH 155





187


xix

List of Tables














106





138


xx







xxi



α alpha


atm atmosphere

β beta


br broad


Bu butyl

C Celsius

ca circa

calcd calculated

CD cyclodextrin


C6H5Br bromobenzene



Cy cyclohexyl

δ chemical shift

xxii

deg degrees

d doublet

Da Dalton








eq equivalent(s)


Et ethyl

Et2O diethyl ether


γ gamma


g gram


GOF goodness of fit

xxiii

h hour





Hz Hertz



K Kelvin

kcal kilocalories

m meta

m multiplet


Me methyl


MHz megahertz

μL microliter

μmol micromole

mg milligram

min minute

xxiv

mL milliliter

mmol millimole


MS molecular sieves

nPr n-propyl





o ortho

π pi

p para



Ph phenyl

Ph2O diphenyl ether



q quartet

quint quintet

xxv


RT room temperature

σ sigma

s singlet

t triplet

tBu tert-butyl

THF tetrahydrofuran


TMS trimethylsilyl


tol toluene

wt weight

1














chemicals6-8















2






























3








rhombohedral36







industries35-36

112 Boron chemistry















4



















12 Catalysis



5


















131 Early discovery












6





















to boron73





7






under vacuum79-80













8



















9


adduct at 195 K














10










12)105









discussed







11




1342 Alkenes










1343 Alkynes








12

















13


(Scheme 110 right)



1345 CO2 and SO2










111 c)

14

Mes2P B(C6F5)2

EO2Mes2P B(C6F5)2

E O

O

R R

gt -20 degC- CO2

tBu3P B(C6F5)3EO2

80 degC- CO2

PB(C6F5)3E

O

O

tBu3


O

O

AlX3

CO2

b)

a)

c)
















15


(bottom) FLPs

















16

B(C6F5)2R2P

FF

F F

H

H

O

HPhB(C6F5)2R2P

FF

F F

H O

Ph

R = tBu Mes


borohydride FLP
















17



14 Scope of Thesis













reactions







18



















101002anie201503087





19



21 Introduction

211 Hydrogenation




















20





















RhPh3P

Ph3P Cl

PPh3

(a) (b) (c)

(d)

21






















(a) (b)

22


























23













HB(C6F5)2247









24























25






















26

















27







(Figure 25)



12 h

9 h

6 h

3 h

15 h

05 h

$

HB HA

28







(Figure 26)
















29




30



























the borane



31


























32


















33



ppm [HB(C6F5)3]-)
















45 degC

75 degC

95 degC

65 degC

115 degC

55 degC

85 degC

105 degC

34
















21

23

35





computations














36















37


















38










interaction121





















39















in Figure 213

40

HB(C6F5)3

NH

OCH3

B(C6F5)3

Ph

+ CH3OH

NH2

OCH3

Ph

NH2Ph

HB(C6F5)3

NHPh

OCH3

220

212

H2

B(C6F5)3

H2













41






(Scheme 212)


= C6F5 221a and X = H 221b)






42



tol (c)













a)

b)

c)

43

















44














acetonitrile)261









45

NH2

R

OCH3

110 oC

NHR

OCH3

NHR

OCH3

(F5C6)3B

+ H2

B(C6F5)3

H2

HB(C6F5)3

- H2HN

R

CH3OB(C6F5)3

+ H2

HB(C6F5)3

HNR

- CH3OH





















46










redelivery262







47














48













49

















explored


50
















a) b) c)

51








52






B(C6F5)3












53


























54



N(2) pyridine










NN NN

B

B(C6F5)3

(C6F5)3B H

- C6F5H H2

235

(C6F5)2





55






























56

23 Conclusions








rings





pyridines264
















57



























capabilities




58







0186 mmol 95)





















5071 H 258 N 211 Found C 5027 H 287 N 219

59



















252








as a white powder

60
























N 209




61








219












386 N 212










62


359 N 214










C 5014 H 348 N 209











4945 H 329 N 230





63







5011 H 350 N 216











5087 H 399 N 212











64



395 N 187













5358 H 323 N 195 Found C 5374 H 300 N 189









228 Found C 4686 H 247 N 232



65









4973 H 333 N 221






















66











299 N 208 Found C 4804 H 307 N 210














270 N 209 Found C 4793 H 282 N 203




67































68















610 μmol 89)









B(C6F5)4)




69









C6D5Br) δ -238 (d 1JB-H = 78 Hz BH)



















70
























solid





71

















N 223 Found C 4764 H 290 N 222




4660 H 247 N 211






72








(Et)






















73






























74































75




5026 H 330 N 209













N 198 Found C 5214 H 358 N 196











76













observed

















77


H 325 N 347 Found C 5611 H 313 N 321




















526 (CH2CHN) 308 (CH2) 245 (CH2) 229 (CH2) 188 (CH2)






Found C 5347 H 291 N 209

78


crystals)












(PiperidineCH2)













SRSRSR diastereomer



79




























2) and Fo




80







81



24 24rsquo 25


Formula wt 65526 64719 69532



a(Aring) 97241(8) 116228(4) 126342(6)

b(Aring) 147348(12) 181284(7) 181939(8)

c(Aring) 188022(15) 236578(9) 128612(6)

α(ordm) 9000 9000 9000

β(ordm) 98826(4) 9000 90269(2)

γ(ordm) 9000 9000 9000

V(Aring3) 26621(4) 49848(3) 29563(2)

Z 4 8 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1635 1725 1562

Abs coeff μ mm-1 0169 0179 0157


Rint 00336 00297 00369

Data used 4685 8773 5207


R (gt2σ) 00361 00315 00352

wR2 00898 00758 00947

GOF 1007 1021 1024

82


216a 218 219


Formula wt 67325 67123 71533



a(Aring) 97677(6) 104368(7) 18886(4)

b(Aring) 147079(11) 93382(7) 16050(3)

c(Aring) 190576(14) 273881(18) 19128(4)

α(ordm) 9000 9000 9000

β(ordm) 98934(2) 96910(3) 9000

γ(ordm) 9000 9000 9000

V(Aring3) 27046(3) 26499(3) 5798(2)

Z 4 4 8

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1653 1683 16388

Abs coeff μ mm-1 0174 0177 0163


Rint 00432 00404 00662

Data used 6164 4676 6654


R (gt2σ) 00522 00496 00687

wR2 01387 01462 01912

GOF 1032 1041 10743

83


220 222 (+05 CH2Cl2) 224 (+05 CH2Cl2)


Formula wt 74737 72573 79380



a(Aring) 173531(15) 17750(5) 109902(9)

b(Aring) 161365(15) 16032(4) 151213(11)

c(Aring) 227522(17) 20783(6) 194765(15)

α(ordm) 9000 9000 90

β(ordm) 9000 96910(3) 92062(3)

γ(ordm) 9000 9000 90

V(Aring3) 63710(9) 5914(3) 32346(4)

Z 8 8 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 15582 16278 1630

Abs coeff μ mm-1 0154 0250 0235


Rint 00406 01159 00306

Data used 7321 5198 5688


R (gt2σ) 00413 00811 00495

wR2 01112 02505 01363

GOF 10647 10628 0936

84


225 227 (+1 C5H12) 228


Formula wt 62721 141861 66727



a(Aring) 101339(5) 137416(4) 95967(15)

b(Aring) 112923(6) 119983(4) 108364(15)

c(Aring) 118209(6) 191036(7) 14143(2)

α(ordm) 98563(2) 9000 75929(5)

β(ordm) 109751(2) 109317(2) 80009(6)

γ(ordm) 94983(2) 9000 76629(5)

V(Aring3) 124520(11) 297240(17) 13772(4)

Z 2 2 2

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1673 1585 1609

Abs coeff μ mm-1 0176 0158 0235


Rint 00211 00246 00351

Data used 4357 5230 4743


R (gt2σ) 00371 00324 00546

wR2 00964 00816 01728

GOF 1044 1014 1028

85


229 (+05 C6H5Br) 230 231a


Formula wt 80784 66727 70733



a(Aring) 201550(11) 97752(4) 112914(4)

b(Aring) 133628(11) 120580(4) 183705(7)

c(Aring) 266328(18) 121120(5) 145648(5)

α(ordm) 9000 102296(2) 9000

β(ordm) 111905(6) 100079(2) 90480(2)

γ(ordm) 9000 90901(2) 9000

V(Aring3) 66551(8) 137127(9) 302105(19)

Z 8 2 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1613 1616 1555

Abs coeff μ mm-1 0749 0165 0155


Rint 00530 00245 00383

Data used 7644 4841 7630


R (gt2σ) 00651 00362 00778

wR2 01802 00971 02335

GOF 1037 1036 1007

86


231b (+05 C6H14) 233 234a (+1 CH2Cl2)


Formula wt 74840 80642 78621



a(Aring) 107250(6) 99895(4) 181314(6)

b(Aring) 112916(7) 115666(5) 135137(5)

c(Aring) 136756(8) 155410(6) 253612(9)

α(ordm) 70523(2) 9000 9000

β(ordm) 88868(2) 105054(2) 92594(2)

γ(ordm) 86934(2) 9000 9000

V(Aring3) 155914(16) 173405(12) 62077(4)

Z 2 2 8

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1594 1544 1677

Abs coeff μ mm-1 0155 0147 0327


Rint 00233 00381 00512

Data used 5479 8395 7383


R (gt2σ) 00371 00400 00816

wR2 01066 00893 02554

GOF 0926 1011 1024

87


234b 235 (+1 C4H8O +1 CH2Cl2)


Formula wt 70128 120323



a(Aring) 100455(5) 113115(7)

b(Aring) 118185(5) 117849(8)

c(Aring) 245940(11) 188035(12)

α(ordm) 9000 83850(3)

β(ordm) 96724(2) 88364(3)

γ(ordm) 9000 69766(3)

V(Aring3) 28998(2) 23383(3)

Z 4 2

Temp (K) 150(2) 150(2)

d(calc) gcm-3 1606 1709



Rint 00342 00265

Data used 5101 8235

Variables 433 712

R (gt2σ) 00438 00473

wR2 01153 01198

GOF 1012 1015

88



31 Introduction


























89



















(Scheme 32 b)275

90










33)277


alcohols



91

















molecular sieves

92
























93


hydrogenation





















94
















$ $ 12

11

10

9

8

7

6

5

4

3

2

1

95


















96




1 n-C3H7 n-C3H7 gt99 (91) gt99 70 52

2 Me iPr gt99 (76) gt99 44 42

3 Me CH2tBu gt99 gt99 (90) 22 14

4 Me n-C5H11 93 (85) 50 (43) 58 41

5 Me CH2Cl gt99 (85) gt99 91 82

6 Me Cy 77 - - -


8 Et n-C4H9 gt99 (87) 95 44 38

9 Et CH2iPr 40 47 - -



12 Me n-CH2CH2Ph gt99 (84) 69 58 24




16 -(CH2)5- 53 41 - -

17 -(2-iPr-5-Me)C5H8- gt99 (88) 89 47 45

18 Cy H 32 - - -





97





















98












mechanism






99

























100





















101










1 n-C3H7 n-C3H7 92

2 Me iPr 57

3 Me CH2Cl gt99

4 Me 2-butyl 53

5 Et iPr gt99

6 Et CH2iPr 40

7 Me Cy 18

8 Me Ph 20

9 Ph Ph 20

10 Et CH2Ph 25

11 Me n-CH2CH2Ph 25

12 -(CH2)5- 28

13 -(CH2)3CH=CH- 0

14 -(2-iPr-5-Me)C5H8- 62


102









R R1

OH

H

B(C6F5)3

R R1

O

+

B(C6F5)3

R R1

O NEt4

HB(C6F5)3

NEt4

B(C6F5)3

B(C6F5)3

R R1

O

05 H2

05 H2















103




























104



















a) b)

a)

b)

105










ca 70 ppm












106



1 Me iPr gt99 79 77 62 81 gt99

2 Me 2-butyl gt99 74 72 46 75 gt99

3 Me CH2tBu gt99 52 41 40 53 gt99


5 Me Cy gt99 81 62 31 64 gt99

6 Me n-C5H11 gt99 63 56 36 73 gt99

7 Et iPr gt99 75 75 69 80 gt99

8 Et n-C4H9 95 93 95 58 gt99 93

9 n-C3H7 n-C3H7 gt99 - - - - 92

10a Me Ph 30 13 15 10 27 trace

11 CH2CH2Cl Ph 54 - - - - 50

12 CF3 Ph 20 - - - - 20

13 Me o-CF3C6H4 trace - - - - 25

14 Me p-MeSO2C6H4 60 - - - - 97


16 Me CH2(o-FC6H4) 75 70 69 66 34 gt99

17 Me CH2(p-FC6H4) gt99 49 31 55 48 gt99


19 Et CH2Ph gt68 20 31 28 46 gt99

20 -(CH2)5- gt99 72 65 68 90 gt99


22 -(2-iPr-5-Me)C5H8- gt99 70 60 60 80 gt99

23 Cy H 10 - - - - 44

24 Ph2CH H 47 - - - - 86

25 PhCH(Me) H 20 - - - - 35


107












activity















108

















1 H Me CH2 92

2 CF3 Me CH2 95


cis 4

4 H iPr C(Me)2 75

109
















catalytically



1 H Ph 81

2 CH3O Ph 85

3 Br Ph 67

4 tBu Ph gt99

5 CH3 p-CH3C6H4 75

6 CF3 Ph 10

7 H o-CH3C6H4 20

110












and MS








111


















112












approaches62



0 mol

5 mol

10 mol

50 mol


113







in 17 - 25 yield259











33 Conclusions










114































115






protocol105






















116














observed















117































118










(80 eq)




















119


















0320 mmol 92)




247 (d 1JB-H = 91 Hz BH)









120



material ketone











GC-MS
















121






















alcohol products







122



= 731 [M-CH3] 551 [M-CH5O]













CH3] 790 [M-CH3]





1101 [M- H2O] 831 [M-C2H5O]






123


C2H5] 591 [M-C3H7]






691 [M-C2H7O] 590 [M-C4H9]






CH2iPr]





770 [M-C2H5O]







591[M-C7H7]



124





[M-C3H7O]























CH2F3O]

125




4029 min mz = 1001 [M] 821 [M-H2O]








951 [M-C3H9O] 811 [M-C4H12O]










561 [M-C2H6O] 450 [C2H5O]




126











C2H4Cl]






C6H4CF3) 1315 (C3) 1314 (C1) 1294 (C4) 1264 (C2) 1244 (C5) 1240 (CF3) 653


1720 [M-H2O] 1450 [M-C2H5O]










1811 [M-OH] 1671 [M-CH3O]

127





1211 [M-CH3] 1051 [M-CH3O]



alcohol products













1451 [M-C2H3] 1031 [M-CF3]







128














alcohol products











1211 [M-C6H5] 911 [M-C7H7O] 771 [M-C8H9O]





129


mz = 2480 [M+2] 2460 [M] 1671 [M-Br] 911 [M-C6H4Br]







CH3) 911 [C7H7]





[M] 1811 [M-CH3) 1661 [M-2(CH3)] 1051 [M-C7H7] 911 [M- C8H9]







1591 [M-C6H5] 911 [C7H7]


776 (m 2H o-Ph) 767 - 761 (m 3H m p-Ph) 759 - 754 (m 4H




GC-MS 12844 min mz = 1821 [M] 1671 [M-CH3]

130





15761 min mz = 1941 [M] 1791 [M-CH3] 1651 [M-C2H5]















2) and Fo










131



31 (+05 C6D5Br)


Formula wt 100893


Space group P2(1)c

a(Aring) 127865(6)

b(Aring) 199241(9)

c(Aring) 170110(7)

α(ordm) 9000

β(ordm) 1067440(10)

γ(ordm) 9000

V(Aring3) 41500(3)

Z 4

Temp (K) 150(2)

d(calc) gcm-3 1607



Rint 00368

Data used 9534

Variables 596

R (gt2σ) 00458

wR2 01145

GOF 1020

132



41 Introduction

411 Hydroamination






imines and enamines















133






















134










alkenylboranes

135




















136
















137















138


139
















(a) (b)

140



















141





















142



















143

















(Scheme 412)

(a) (b)

144


























145





146



(Table 42)


















products341






147


alkynes

















148


429 and 430






was not successful











149

















150





yield (Scheme 416)




















151


yield (Scheme 417)







1 H 0 68 434

2 H 1 66 435

3 F 1 72 436

4 CH3O 1 52 437








152







574 ppm (Figure 47)


the zwitterion 439








1H

1H31P

153




















(a) (b)

154




















155



Ph2PH









156









allenes147











157

43 Conclusions


























column prior to use




158

















experiments












159



product as a solid




-30 ordmC








1312 (p-Ph) 1310 (C7) 1307 (m-Ph) 1298 (Ph) 1293 (Ph) 1277 (C8) 1257 (C9) 1254 (o-





EZ ratio 71








CF) 1346 (C2) 1339 (C5) 1319 (C10) 1318 (C7) 1311 (C12) 1310 (C4) 1303 (C9) 1278

(C13) 1274 (C11) 1258 (C14) 1253 (C3 C8) 937 (C15) 619 (C6) 288 (Me) 208 (iPr)

160


296 N 165 Found 6037 H 317 N 173



EZ ratio 71









CD2Cl2) δ 1916 (C1) 1341 (C5) 1323 (C13) 1315 (C15) 1313 (C4) 1307 (C12) 1282 (C16)

1262 (C17) 1257 (C3) 1254 (C11) 699 (C6) 320 (C7) 291 (Me) 249 (C8) 244 (C9) (C2


C 6197 H 328 N 157 Found 6158 H 354 N 153












(C2) 1317 (C11 C14) 1311 (C9) 1309 (C13 C15) 1304 (C4 C10) 1296 (C8) 1294 (C16) 1278

B(C6F5)3

N1

2

3

45

7

8

9

10

14

1516

17

18

6

11

12

13

B(C6F5)3

N1

2

3

45

7

8 9

10

11 12

13

14

1617

1815

6

19

161



156 Found 6259 H 296 N 171




6106 H 262 N 142 EZ ratio 11


(m 2H H3) 730 (m 2H H4) 726 (m 2H H8) 717 (m 2H H15) 707







1364 1 (dm 1JC-F = 246 Hz CF) 1356 (C10) 1348 (C5) 1325 (C2) 1313 (C7) 1310 (C15)

1305(C8) 1297 (C4) 1292 (C3) 1278 (C16) 1274 (C14) 1269 (C11) 1257 (C17) 1255 (C9)

1155 (C12) 937 (C18) 557 (OMe) 283 (Me)


(m 2H H4) 730 (m 2H H3) 726 (m 2H H8) 717 (m 2H H12) 702 (m



1345 (C10) 1325 (C2) 1319 (C7) 1310 (C3) 1297 (C4) 1257 (C11) 1255








162



















Found 5885 H 366 N 154









163










129 Found C 6812 H 306 N 134














5702 H 323 N 180 Found 5667 H 330 N 179





164









1312 (C9) 1290 (C12) 1286 (C4) 1272 (C8) 1269 (C13) 1239 (C14) 593 (C6) 214 (Me)


















(560 mg 0733 mmol 99)

165








(C4) 1310 (C1) 1307 (C3) 1296 (C6) 1283 (C8) 1258 (C5) 1237 (C2) 941 (C9) 654 (tBu)


174











5318 H 304 N 194







solid

166












numerous attempts














Found 6059 H 281 N 197

167

























C21H20NO 30215449 Found 30215453

168



C6H5) 715 - 708 (m 6H o-C6H5 H3 H4) 706 -701 (m 1H H2) 700-



C6H5) 1390 (C1) 1364 (C6) 1309 (C5 C2) 1291 (m-C6H5) 1281 (C4) 1259 (C3) 1255 (o-


28615957 Found 28615986



H7) 771 - 768 (m 2H H2 H4) 752 (tm 3JH-H = 85 Hz 1H H9) 743




1371 (C1) 1341 (C6) 1319 (C5) 1292 (m-C6H5) 1288 (C7 C2) 1281 (C4) 1266 (C9) 1260








1293 (m-C6H5) 1286 (C3) 1285 (C4) 1276 (C2) 1243 (o-C6H5) 1228 (p-C6H5) 1082








169


1327 (C2) 1296 (C4) 1291 (m-C6H5) 1275 (C3) 1256 (o-C6H5) 1235 (p-C6H5) 1224 (C6)














(m 1H H4) 707 - 702 (m 5H H3 H8) 697 (m 1H H5) 691 (m






C20H15F3N 32611566 Found 32611576



= 36 Hz 4JH-H = 12 Hz 1H H2) 705 - 701 (m 4H H6) 695 - 689




170



31408200






(C1) 1446 (C=CH2) 1296 (m-C6H5) 1274 (C2) 1260 (C3) 1253 (C4) 1208 (o-C6H5) 1206


Found 2441166









(C5) 1306 (C4) 1294 (C2) 1292 (m-C6H5) 1291 (C7) 1273 (C9) 1271 (C8 C13) 1268 (C12)






H2) 788 (dm 3JH-H = 74 Hz 1H H7) 767- 762 (m 3H H9 H12




171


(C1) 1316 (C3) 1308 (C6) 1307 (C5) 1306 (C4) 1296 (C2) 1291 (C7) 1274 (C9) 1272 (C8


Found 40815576



H6) 701 (m 4H H8) 697- 691 (m 5H H4 H9) 516 (s 1H =CH2)






for C20H15F3N 32611566 Found 32611485
















172





34013065
















CD2Cl2) δ 728 - 720 (m 2H H2 H5) 708 - 700 (m 2H H3 H4)







173


C20H17F3N 32813131 Found 32813189
























174





















0103 mmol 54)









NB(C6F5)3

4

3

2

1

175










(427 mg 0265 mmol 68)









(451 mg 0257 mmol 66)








176




1H H4) 135 (m 1H H1) 121 (m 1H H3) 113 (m 2H H23) 102 (m 1H H2)






















177




























178








5314 H 432





















179





























180










2) and Fo


















181



41 47 48


Formula wt 88546 108572 77939



a(Aring) 91451(8) 120520(8) 99293(9)

b(Aring) 20583(2) 122120(8) 115709(11)

c(Aring) 20738(2) 184965(12) 168258(15)

α(ordm) 9000 103236(4) 75826(4)

β(ordm) 96295(4) 104461(4) 77700(4)

γ(ordm) 9000 104447(4) 65591(4)

V(Aring3) 38800(6) 24264(3) 16930(3)

Z 4 2 2

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1516 1482 1529

Abs coeff μ mm-1 0138 0126 0146


Rint 00444 00308 00308

Data used 8910 11131 5899


R (gt2σ) 00420 00532 00488

wR2 00964 01380 01380

GOF 1018 1028 1026

182


49 410

(+05 C5H12)

413

(+1 C2H4Cl2)


Formula wt 86350 85145 98643



a(Aring) 174202(13) 113739(5) 138815(4)

b(Aring) 135941(10) 115489(6) 242842(7)

c(Aring) 174144(13) 158094(7) 146750(4)

α(ordm) 9000 92979(2) 9000

β(ordm) 118149(3) 97298(2) 1108840(10)

γ(ordm) 9000 116865(3) 9000

V(Aring3) 36362(5) 182343(15) 46220(2)

Z 4 2 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1577 1536 1418

Abs coeff μ mm-1 0256 0143 0236


Rint 00299 00352 00437

Data used 6409 8342 8147


R (gt2σ) 00570 00504 00687

wR2 01537 01410 02122

GOF 1045 1021 1092

183


414

(+05 CH2Cl2 +1 C5H12)

432

(+05 C5H12) 439


Formula wt 96404 72131 110070



a(Aring) 309455(12) 80774(6) 117846(13)

b(Aring) 193567(7) 117730(8) 159017(19)

c(Aring) 182668(6) 158569(11) 16349(2)

α(ordm) 9000 79707(3) 108194(4)

β(ordm) 123002(2) 86387(3) 107588(4)

γ(ordm) 9000 87902(3) 104551(4)

V(Aring3) 91764(6) 148021(18) 25646(5)

Z 8 2 2

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1397 1620 1425

Abs coeff μ mm-1 0179 0160 0179


Rint 00476 00352 00284

Data used 8097 6615 9023


R (gt2σ) 00716 00560 00339

wR2 02417 01703 00880

GOF 1047 1096 1019

184


440 442





a(Aring) 329294(17) 114236(2)

b(Aring) 118317(6) 151074(3)

c(Aring) 206088(10) 192749(4)

α(ordm) 9000 9000

β(ordm) 107535(5) 93553(1)

γ(ordm) 9000 9000

V(Aring3) 76563(7) 332009(11)

Z 8 4

Temp (K) 150(2) 223(2)

d(calc) gcm-3 1479 1449



Rint 00316 0055

Data used 8776 6697

Variables 517 456

R (gt2σ) 00365 00672

wR2 01017 01623

GOF 1021 1048

185


51 Thesis Summary




























186




















also described

52 Future Work









187
























188







189

References




2008 1 636-639




Am Chem Soc 1955 77 1708-1710









15 Monnin E Science 2001 291 112-114





190





2011 333 863-866





27 Power P P Nature 2010 463 171-177













191








Commun 2000 3 530-533








Catal A Chem 1996 111 67-79








192



















2010 132 9604-9606



2009 1534-1541


193


















Int Ed 2008 47 7543-7546




194




Chem Int Ed 2012 51 10164-10168


2013 5 718-723




Synth Catal 2011 353 2093-2110















195




















196


2015 DOI 101039C4CY01716A








Chem Soc 2009 131 12280-12289


Chem Soc 2009 131 12280-12289












197












2013 135 9326-9329


2014 136 10708-10717




2011 6771-6777







198


Trans 2012 41 4310-4312




1998 17 1369-1377


















199






Chem Soc 2006 128 8724-8725










212 Davey S Nat Chem 2012 4 337-337










200







2012 51 4452-4455


















201










Chem Int Ed 2010 49 6559-6563












202





Chem 1996 61 3849-3862




















Chem Soc 2012 134 10843-10851

203



















Chem 1978 43 374-375






204


305 Trost B Science 1991 254 1471-1477





















Commun 2007 0 278-279

205








Commun 2014 50 1980-1982


Chem Soc 2013 136 777-782













206














iv

Acknowledgments



















keeping us in check










v

Table of Contents

Abstract ii

Acknowledgments iv

Table of Contents v

List of Figures xi

List of Schemes xiv

List of Tables xix






12 Catalysis 4







1342 Alkenes 11

1343 Alkynes 11


1345 CO2 and SO2 13



vi




21 Introduction 19





















vii





23 Conclusions 56









31 Introduction 88










viii










33 Conclusions 113















ix




41 Introduction 132



















x





43 Conclusions 157

















52 Future Work 186

References 189

xi

List of Figures



















ppm [HB(C6F5)3]-) 33





xii






tol (c) 42














N(2) pyridine 54




xiii







104







136











xiv

List of Schemes








adduct at 195 K 9











(bottom) FLPs 15


borohydride FLP 16

xv


















= C6F5 221a and X = H 221b) 41





xvi






alcohols 90





hydrogenation 93












xvii





alkenylboranes 134




136





with [(Et2O)2H][B(C6F5)4] 141







alkynes 147


429 and 430 148

xviii













Ph2PH 155





187


xix

List of Tables














106





138


xx







xxi



α alpha


atm atmosphere

β beta


br broad


Bu butyl

C Celsius

ca circa

calcd calculated

CD cyclodextrin


C6H5Br bromobenzene



Cy cyclohexyl

δ chemical shift

xxii

deg degrees

d doublet

Da Dalton








eq equivalent(s)


Et ethyl

Et2O diethyl ether


γ gamma


g gram


GOF goodness of fit

xxiii

h hour





Hz Hertz



K Kelvin

kcal kilocalories

m meta

m multiplet


Me methyl


MHz megahertz

μL microliter

μmol micromole

mg milligram

min minute

xxiv

mL milliliter

mmol millimole


MS molecular sieves

nPr n-propyl





o ortho

π pi

p para



Ph phenyl

Ph2O diphenyl ether



q quartet

quint quintet

xxv


RT room temperature

σ sigma

s singlet

t triplet

tBu tert-butyl

THF tetrahydrofuran


TMS trimethylsilyl


tol toluene

wt weight

1














chemicals6-8















2






























3








rhombohedral36







industries35-36

112 Boron chemistry















4



















12 Catalysis



5


















131 Early discovery












6





















to boron73





7






under vacuum79-80













8



















9


adduct at 195 K














10










12)105









discussed







11




1342 Alkenes










1343 Alkynes








12

















13


(Scheme 110 right)



1345 CO2 and SO2










111 c)

14

Mes2P B(C6F5)2

EO2Mes2P B(C6F5)2

E O

O

R R

gt -20 degC- CO2

tBu3P B(C6F5)3EO2

80 degC- CO2

PB(C6F5)3E

O

O

tBu3


O

O

AlX3

CO2

b)

a)

c)
















15


(bottom) FLPs

















16

B(C6F5)2R2P

FF

F F

H

H

O

HPhB(C6F5)2R2P

FF

F F

H O

Ph

R = tBu Mes


borohydride FLP
















17



14 Scope of Thesis













reactions







18



















101002anie201503087





19



21 Introduction

211 Hydrogenation




















20





















RhPh3P

Ph3P Cl

PPh3

(a) (b) (c)

(d)

21






















(a) (b)

22


























23













HB(C6F5)2247









24























25






















26

















27







(Figure 25)



12 h

9 h

6 h

3 h

15 h

05 h

$

HB HA

28







(Figure 26)
















29




30



























the borane



31


























32


















33



ppm [HB(C6F5)3]-)
















45 degC

75 degC

95 degC

65 degC

115 degC

55 degC

85 degC

105 degC

34
















21

23

35





computations














36















37


















38










interaction121





















39















in Figure 213

40

HB(C6F5)3

NH

OCH3

B(C6F5)3

Ph

+ CH3OH

NH2

OCH3

Ph

NH2Ph

HB(C6F5)3

NHPh

OCH3

220

212

H2

B(C6F5)3

H2













41






(Scheme 212)


= C6F5 221a and X = H 221b)






42



tol (c)













a)

b)

c)

43

















44














acetonitrile)261









45

NH2

R

OCH3

110 oC

NHR

OCH3

NHR

OCH3

(F5C6)3B

+ H2

B(C6F5)3

H2

HB(C6F5)3

- H2HN

R

CH3OB(C6F5)3

+ H2

HB(C6F5)3

HNR

- CH3OH





















46










redelivery262







47














48













49

















explored


50
















a) b) c)

51








52






B(C6F5)3












53


























54



N(2) pyridine










NN NN

B

B(C6F5)3

(C6F5)3B H

- C6F5H H2

235

(C6F5)2





55






























56

23 Conclusions








rings





pyridines264
















57



























capabilities




58







0186 mmol 95)





















5071 H 258 N 211 Found C 5027 H 287 N 219

59



















252








as a white powder

60
























N 209




61








219












386 N 212










62


359 N 214










C 5014 H 348 N 209











4945 H 329 N 230





63







5011 H 350 N 216











5087 H 399 N 212











64



395 N 187













5358 H 323 N 195 Found C 5374 H 300 N 189









228 Found C 4686 H 247 N 232



65









4973 H 333 N 221






















66











299 N 208 Found C 4804 H 307 N 210














270 N 209 Found C 4793 H 282 N 203




67































68















610 μmol 89)









B(C6F5)4)




69









C6D5Br) δ -238 (d 1JB-H = 78 Hz BH)



















70
























solid





71

















N 223 Found C 4764 H 290 N 222




4660 H 247 N 211






72








(Et)






















73






























74































75




5026 H 330 N 209













N 198 Found C 5214 H 358 N 196











76













observed

















77


H 325 N 347 Found C 5611 H 313 N 321




















526 (CH2CHN) 308 (CH2) 245 (CH2) 229 (CH2) 188 (CH2)






Found C 5347 H 291 N 209

78


crystals)












(PiperidineCH2)













SRSRSR diastereomer



79




























2) and Fo




80







81



24 24rsquo 25


Formula wt 65526 64719 69532



a(Aring) 97241(8) 116228(4) 126342(6)

b(Aring) 147348(12) 181284(7) 181939(8)

c(Aring) 188022(15) 236578(9) 128612(6)

α(ordm) 9000 9000 9000

β(ordm) 98826(4) 9000 90269(2)

γ(ordm) 9000 9000 9000

V(Aring3) 26621(4) 49848(3) 29563(2)

Z 4 8 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1635 1725 1562

Abs coeff μ mm-1 0169 0179 0157


Rint 00336 00297 00369

Data used 4685 8773 5207


R (gt2σ) 00361 00315 00352

wR2 00898 00758 00947

GOF 1007 1021 1024

82


216a 218 219


Formula wt 67325 67123 71533



a(Aring) 97677(6) 104368(7) 18886(4)

b(Aring) 147079(11) 93382(7) 16050(3)

c(Aring) 190576(14) 273881(18) 19128(4)

α(ordm) 9000 9000 9000

β(ordm) 98934(2) 96910(3) 9000

γ(ordm) 9000 9000 9000

V(Aring3) 27046(3) 26499(3) 5798(2)

Z 4 4 8

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1653 1683 16388

Abs coeff μ mm-1 0174 0177 0163


Rint 00432 00404 00662

Data used 6164 4676 6654


R (gt2σ) 00522 00496 00687

wR2 01387 01462 01912

GOF 1032 1041 10743

83


220 222 (+05 CH2Cl2) 224 (+05 CH2Cl2)


Formula wt 74737 72573 79380



a(Aring) 173531(15) 17750(5) 109902(9)

b(Aring) 161365(15) 16032(4) 151213(11)

c(Aring) 227522(17) 20783(6) 194765(15)

α(ordm) 9000 9000 90

β(ordm) 9000 96910(3) 92062(3)

γ(ordm) 9000 9000 90

V(Aring3) 63710(9) 5914(3) 32346(4)

Z 8 8 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 15582 16278 1630

Abs coeff μ mm-1 0154 0250 0235


Rint 00406 01159 00306

Data used 7321 5198 5688


R (gt2σ) 00413 00811 00495

wR2 01112 02505 01363

GOF 10647 10628 0936

84


225 227 (+1 C5H12) 228


Formula wt 62721 141861 66727



a(Aring) 101339(5) 137416(4) 95967(15)

b(Aring) 112923(6) 119983(4) 108364(15)

c(Aring) 118209(6) 191036(7) 14143(2)

α(ordm) 98563(2) 9000 75929(5)

β(ordm) 109751(2) 109317(2) 80009(6)

γ(ordm) 94983(2) 9000 76629(5)

V(Aring3) 124520(11) 297240(17) 13772(4)

Z 2 2 2

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1673 1585 1609

Abs coeff μ mm-1 0176 0158 0235


Rint 00211 00246 00351

Data used 4357 5230 4743


R (gt2σ) 00371 00324 00546

wR2 00964 00816 01728

GOF 1044 1014 1028

85


229 (+05 C6H5Br) 230 231a


Formula wt 80784 66727 70733



a(Aring) 201550(11) 97752(4) 112914(4)

b(Aring) 133628(11) 120580(4) 183705(7)

c(Aring) 266328(18) 121120(5) 145648(5)

α(ordm) 9000 102296(2) 9000

β(ordm) 111905(6) 100079(2) 90480(2)

γ(ordm) 9000 90901(2) 9000

V(Aring3) 66551(8) 137127(9) 302105(19)

Z 8 2 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1613 1616 1555

Abs coeff μ mm-1 0749 0165 0155


Rint 00530 00245 00383

Data used 7644 4841 7630


R (gt2σ) 00651 00362 00778

wR2 01802 00971 02335

GOF 1037 1036 1007

86


231b (+05 C6H14) 233 234a (+1 CH2Cl2)


Formula wt 74840 80642 78621



a(Aring) 107250(6) 99895(4) 181314(6)

b(Aring) 112916(7) 115666(5) 135137(5)

c(Aring) 136756(8) 155410(6) 253612(9)

α(ordm) 70523(2) 9000 9000

β(ordm) 88868(2) 105054(2) 92594(2)

γ(ordm) 86934(2) 9000 9000

V(Aring3) 155914(16) 173405(12) 62077(4)

Z 2 2 8

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1594 1544 1677

Abs coeff μ mm-1 0155 0147 0327


Rint 00233 00381 00512

Data used 5479 8395 7383


R (gt2σ) 00371 00400 00816

wR2 01066 00893 02554

GOF 0926 1011 1024

87


234b 235 (+1 C4H8O +1 CH2Cl2)


Formula wt 70128 120323



a(Aring) 100455(5) 113115(7)

b(Aring) 118185(5) 117849(8)

c(Aring) 245940(11) 188035(12)

α(ordm) 9000 83850(3)

β(ordm) 96724(2) 88364(3)

γ(ordm) 9000 69766(3)

V(Aring3) 28998(2) 23383(3)

Z 4 2

Temp (K) 150(2) 150(2)

d(calc) gcm-3 1606 1709



Rint 00342 00265

Data used 5101 8235

Variables 433 712

R (gt2σ) 00438 00473

wR2 01153 01198

GOF 1012 1015

88



31 Introduction


























89



















(Scheme 32 b)275

90










33)277


alcohols



91

















molecular sieves

92
























93


hydrogenation





















94
















$ $ 12

11

10

9

8

7

6

5

4

3

2

1

95


















96




1 n-C3H7 n-C3H7 gt99 (91) gt99 70 52

2 Me iPr gt99 (76) gt99 44 42

3 Me CH2tBu gt99 gt99 (90) 22 14

4 Me n-C5H11 93 (85) 50 (43) 58 41

5 Me CH2Cl gt99 (85) gt99 91 82

6 Me Cy 77 - - -


8 Et n-C4H9 gt99 (87) 95 44 38

9 Et CH2iPr 40 47 - -



12 Me n-CH2CH2Ph gt99 (84) 69 58 24




16 -(CH2)5- 53 41 - -

17 -(2-iPr-5-Me)C5H8- gt99 (88) 89 47 45

18 Cy H 32 - - -





97





















98












mechanism






99

























100





















101










1 n-C3H7 n-C3H7 92

2 Me iPr 57

3 Me CH2Cl gt99

4 Me 2-butyl 53

5 Et iPr gt99

6 Et CH2iPr 40

7 Me Cy 18

8 Me Ph 20

9 Ph Ph 20

10 Et CH2Ph 25

11 Me n-CH2CH2Ph 25

12 -(CH2)5- 28

13 -(CH2)3CH=CH- 0

14 -(2-iPr-5-Me)C5H8- 62


102









R R1

OH

H

B(C6F5)3

R R1

O

+

B(C6F5)3

R R1

O NEt4

HB(C6F5)3

NEt4

B(C6F5)3

B(C6F5)3

R R1

O

05 H2

05 H2















103




























104



















a) b)

a)

b)

105










ca 70 ppm












106



1 Me iPr gt99 79 77 62 81 gt99

2 Me 2-butyl gt99 74 72 46 75 gt99

3 Me CH2tBu gt99 52 41 40 53 gt99


5 Me Cy gt99 81 62 31 64 gt99

6 Me n-C5H11 gt99 63 56 36 73 gt99

7 Et iPr gt99 75 75 69 80 gt99

8 Et n-C4H9 95 93 95 58 gt99 93

9 n-C3H7 n-C3H7 gt99 - - - - 92

10a Me Ph 30 13 15 10 27 trace

11 CH2CH2Cl Ph 54 - - - - 50

12 CF3 Ph 20 - - - - 20

13 Me o-CF3C6H4 trace - - - - 25

14 Me p-MeSO2C6H4 60 - - - - 97


16 Me CH2(o-FC6H4) 75 70 69 66 34 gt99

17 Me CH2(p-FC6H4) gt99 49 31 55 48 gt99


19 Et CH2Ph gt68 20 31 28 46 gt99

20 -(CH2)5- gt99 72 65 68 90 gt99


22 -(2-iPr-5-Me)C5H8- gt99 70 60 60 80 gt99

23 Cy H 10 - - - - 44

24 Ph2CH H 47 - - - - 86

25 PhCH(Me) H 20 - - - - 35


107












activity















108

















1 H Me CH2 92

2 CF3 Me CH2 95


cis 4

4 H iPr C(Me)2 75

109
















catalytically



1 H Ph 81

2 CH3O Ph 85

3 Br Ph 67

4 tBu Ph gt99

5 CH3 p-CH3C6H4 75

6 CF3 Ph 10

7 H o-CH3C6H4 20

110












and MS








111


















112












approaches62



0 mol

5 mol

10 mol

50 mol


113







in 17 - 25 yield259











33 Conclusions










114































115






protocol105






















116














observed















117































118










(80 eq)




















119


















0320 mmol 92)




247 (d 1JB-H = 91 Hz BH)









120



material ketone











GC-MS
















121






















alcohol products







122



= 731 [M-CH3] 551 [M-CH5O]













CH3] 790 [M-CH3]





1101 [M- H2O] 831 [M-C2H5O]






123


C2H5] 591 [M-C3H7]






691 [M-C2H7O] 590 [M-C4H9]






CH2iPr]





770 [M-C2H5O]







591[M-C7H7]



124





[M-C3H7O]























CH2F3O]

125




4029 min mz = 1001 [M] 821 [M-H2O]








951 [M-C3H9O] 811 [M-C4H12O]










561 [M-C2H6O] 450 [C2H5O]




126











C2H4Cl]






C6H4CF3) 1315 (C3) 1314 (C1) 1294 (C4) 1264 (C2) 1244 (C5) 1240 (CF3) 653


1720 [M-H2O] 1450 [M-C2H5O]










1811 [M-OH] 1671 [M-CH3O]

127





1211 [M-CH3] 1051 [M-CH3O]



alcohol products













1451 [M-C2H3] 1031 [M-CF3]







128














alcohol products











1211 [M-C6H5] 911 [M-C7H7O] 771 [M-C8H9O]





129


mz = 2480 [M+2] 2460 [M] 1671 [M-Br] 911 [M-C6H4Br]







CH3) 911 [C7H7]





[M] 1811 [M-CH3) 1661 [M-2(CH3)] 1051 [M-C7H7] 911 [M- C8H9]







1591 [M-C6H5] 911 [C7H7]


776 (m 2H o-Ph) 767 - 761 (m 3H m p-Ph) 759 - 754 (m 4H




GC-MS 12844 min mz = 1821 [M] 1671 [M-CH3]

130





15761 min mz = 1941 [M] 1791 [M-CH3] 1651 [M-C2H5]















2) and Fo










131



31 (+05 C6D5Br)


Formula wt 100893


Space group P2(1)c

a(Aring) 127865(6)

b(Aring) 199241(9)

c(Aring) 170110(7)

α(ordm) 9000

β(ordm) 1067440(10)

γ(ordm) 9000

V(Aring3) 41500(3)

Z 4

Temp (K) 150(2)

d(calc) gcm-3 1607



Rint 00368

Data used 9534

Variables 596

R (gt2σ) 00458

wR2 01145

GOF 1020

132



41 Introduction

411 Hydroamination






imines and enamines















133






















134










alkenylboranes

135




















136
















137















138


139
















(a) (b)

140



















141





















142



















143

















(Scheme 412)

(a) (b)

144


























145





146



(Table 42)


















products341






147


alkynes

















148


429 and 430






was not successful











149

















150





yield (Scheme 416)




















151


yield (Scheme 417)







1 H 0 68 434

2 H 1 66 435

3 F 1 72 436

4 CH3O 1 52 437








152







574 ppm (Figure 47)


the zwitterion 439








1H

1H31P

153




















(a) (b)

154




















155



Ph2PH









156









allenes147











157

43 Conclusions


























column prior to use




158

















experiments












159



product as a solid




-30 ordmC








1312 (p-Ph) 1310 (C7) 1307 (m-Ph) 1298 (Ph) 1293 (Ph) 1277 (C8) 1257 (C9) 1254 (o-





EZ ratio 71








CF) 1346 (C2) 1339 (C5) 1319 (C10) 1318 (C7) 1311 (C12) 1310 (C4) 1303 (C9) 1278

(C13) 1274 (C11) 1258 (C14) 1253 (C3 C8) 937 (C15) 619 (C6) 288 (Me) 208 (iPr)

160


296 N 165 Found 6037 H 317 N 173



EZ ratio 71









CD2Cl2) δ 1916 (C1) 1341 (C5) 1323 (C13) 1315 (C15) 1313 (C4) 1307 (C12) 1282 (C16)

1262 (C17) 1257 (C3) 1254 (C11) 699 (C6) 320 (C7) 291 (Me) 249 (C8) 244 (C9) (C2


C 6197 H 328 N 157 Found 6158 H 354 N 153












(C2) 1317 (C11 C14) 1311 (C9) 1309 (C13 C15) 1304 (C4 C10) 1296 (C8) 1294 (C16) 1278

B(C6F5)3

N1

2

3

45

7

8

9

10

14

1516

17

18

6

11

12

13

B(C6F5)3

N1

2

3

45

7

8 9

10

11 12

13

14

1617

1815

6

19

161



156 Found 6259 H 296 N 171




6106 H 262 N 142 EZ ratio 11


(m 2H H3) 730 (m 2H H4) 726 (m 2H H8) 717 (m 2H H15) 707







1364 1 (dm 1JC-F = 246 Hz CF) 1356 (C10) 1348 (C5) 1325 (C2) 1313 (C7) 1310 (C15)

1305(C8) 1297 (C4) 1292 (C3) 1278 (C16) 1274 (C14) 1269 (C11) 1257 (C17) 1255 (C9)

1155 (C12) 937 (C18) 557 (OMe) 283 (Me)


(m 2H H4) 730 (m 2H H3) 726 (m 2H H8) 717 (m 2H H12) 702 (m



1345 (C10) 1325 (C2) 1319 (C7) 1310 (C3) 1297 (C4) 1257 (C11) 1255








162



















Found 5885 H 366 N 154









163










129 Found C 6812 H 306 N 134














5702 H 323 N 180 Found 5667 H 330 N 179





164









1312 (C9) 1290 (C12) 1286 (C4) 1272 (C8) 1269 (C13) 1239 (C14) 593 (C6) 214 (Me)


















(560 mg 0733 mmol 99)

165








(C4) 1310 (C1) 1307 (C3) 1296 (C6) 1283 (C8) 1258 (C5) 1237 (C2) 941 (C9) 654 (tBu)


174











5318 H 304 N 194







solid

166












numerous attempts














Found 6059 H 281 N 197

167

























C21H20NO 30215449 Found 30215453

168



C6H5) 715 - 708 (m 6H o-C6H5 H3 H4) 706 -701 (m 1H H2) 700-



C6H5) 1390 (C1) 1364 (C6) 1309 (C5 C2) 1291 (m-C6H5) 1281 (C4) 1259 (C3) 1255 (o-


28615957 Found 28615986



H7) 771 - 768 (m 2H H2 H4) 752 (tm 3JH-H = 85 Hz 1H H9) 743




1371 (C1) 1341 (C6) 1319 (C5) 1292 (m-C6H5) 1288 (C7 C2) 1281 (C4) 1266 (C9) 1260








1293 (m-C6H5) 1286 (C3) 1285 (C4) 1276 (C2) 1243 (o-C6H5) 1228 (p-C6H5) 1082








169


1327 (C2) 1296 (C4) 1291 (m-C6H5) 1275 (C3) 1256 (o-C6H5) 1235 (p-C6H5) 1224 (C6)














(m 1H H4) 707 - 702 (m 5H H3 H8) 697 (m 1H H5) 691 (m






C20H15F3N 32611566 Found 32611576



= 36 Hz 4JH-H = 12 Hz 1H H2) 705 - 701 (m 4H H6) 695 - 689




170



31408200






(C1) 1446 (C=CH2) 1296 (m-C6H5) 1274 (C2) 1260 (C3) 1253 (C4) 1208 (o-C6H5) 1206


Found 2441166









(C5) 1306 (C4) 1294 (C2) 1292 (m-C6H5) 1291 (C7) 1273 (C9) 1271 (C8 C13) 1268 (C12)






H2) 788 (dm 3JH-H = 74 Hz 1H H7) 767- 762 (m 3H H9 H12




171


(C1) 1316 (C3) 1308 (C6) 1307 (C5) 1306 (C4) 1296 (C2) 1291 (C7) 1274 (C9) 1272 (C8


Found 40815576



H6) 701 (m 4H H8) 697- 691 (m 5H H4 H9) 516 (s 1H =CH2)






for C20H15F3N 32611566 Found 32611485
















172





34013065
















CD2Cl2) δ 728 - 720 (m 2H H2 H5) 708 - 700 (m 2H H3 H4)







173


C20H17F3N 32813131 Found 32813189
























174





















0103 mmol 54)









NB(C6F5)3

4

3

2

1

175










(427 mg 0265 mmol 68)









(451 mg 0257 mmol 66)








176




1H H4) 135 (m 1H H1) 121 (m 1H H3) 113 (m 2H H23) 102 (m 1H H2)






















177




























178








5314 H 432





















179





























180










2) and Fo


















181



41 47 48


Formula wt 88546 108572 77939



a(Aring) 91451(8) 120520(8) 99293(9)

b(Aring) 20583(2) 122120(8) 115709(11)

c(Aring) 20738(2) 184965(12) 168258(15)

α(ordm) 9000 103236(4) 75826(4)

β(ordm) 96295(4) 104461(4) 77700(4)

γ(ordm) 9000 104447(4) 65591(4)

V(Aring3) 38800(6) 24264(3) 16930(3)

Z 4 2 2

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1516 1482 1529

Abs coeff μ mm-1 0138 0126 0146


Rint 00444 00308 00308

Data used 8910 11131 5899


R (gt2σ) 00420 00532 00488

wR2 00964 01380 01380

GOF 1018 1028 1026

182


49 410

(+05 C5H12)

413

(+1 C2H4Cl2)


Formula wt 86350 85145 98643



a(Aring) 174202(13) 113739(5) 138815(4)

b(Aring) 135941(10) 115489(6) 242842(7)

c(Aring) 174144(13) 158094(7) 146750(4)

α(ordm) 9000 92979(2) 9000

β(ordm) 118149(3) 97298(2) 1108840(10)

γ(ordm) 9000 116865(3) 9000

V(Aring3) 36362(5) 182343(15) 46220(2)

Z 4 2 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1577 1536 1418

Abs coeff μ mm-1 0256 0143 0236


Rint 00299 00352 00437

Data used 6409 8342 8147


R (gt2σ) 00570 00504 00687

wR2 01537 01410 02122

GOF 1045 1021 1092

183


414

(+05 CH2Cl2 +1 C5H12)

432

(+05 C5H12) 439


Formula wt 96404 72131 110070



a(Aring) 309455(12) 80774(6) 117846(13)

b(Aring) 193567(7) 117730(8) 159017(19)

c(Aring) 182668(6) 158569(11) 16349(2)

α(ordm) 9000 79707(3) 108194(4)

β(ordm) 123002(2) 86387(3) 107588(4)

γ(ordm) 9000 87902(3) 104551(4)

V(Aring3) 91764(6) 148021(18) 25646(5)

Z 8 2 2

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1397 1620 1425

Abs coeff μ mm-1 0179 0160 0179


Rint 00476 00352 00284

Data used 8097 6615 9023


R (gt2σ) 00716 00560 00339

wR2 02417 01703 00880

GOF 1047 1096 1019

184


440 442





a(Aring) 329294(17) 114236(2)

b(Aring) 118317(6) 151074(3)

c(Aring) 206088(10) 192749(4)

α(ordm) 9000 9000

β(ordm) 107535(5) 93553(1)

γ(ordm) 9000 9000

V(Aring3) 76563(7) 332009(11)

Z 8 4

Temp (K) 150(2) 223(2)

d(calc) gcm-3 1479 1449



Rint 00316 0055

Data used 8776 6697

Variables 517 456

R (gt2σ) 00365 00672

wR2 01017 01623

GOF 1021 1048

185


51 Thesis Summary




























186




















also described

52 Future Work









187
























188







189

References




2008 1 636-639




Am Chem Soc 1955 77 1708-1710









15 Monnin E Science 2001 291 112-114





190





2011 333 863-866





27 Power P P Nature 2010 463 171-177













191








Commun 2000 3 530-533








Catal A Chem 1996 111 67-79








192



















2010 132 9604-9606



2009 1534-1541


193


















Int Ed 2008 47 7543-7546




194




Chem Int Ed 2012 51 10164-10168


2013 5 718-723




Synth Catal 2011 353 2093-2110















195




















196


2015 DOI 101039C4CY01716A








Chem Soc 2009 131 12280-12289


Chem Soc 2009 131 12280-12289












197












2013 135 9326-9329


2014 136 10708-10717




2011 6771-6777







198


Trans 2012 41 4310-4312




1998 17 1369-1377


















199






Chem Soc 2006 128 8724-8725










212 Davey S Nat Chem 2012 4 337-337










200







2012 51 4452-4455


















201










Chem Int Ed 2010 49 6559-6563












202





Chem 1996 61 3849-3862




















Chem Soc 2012 134 10843-10851

203



















Chem 1978 43 374-375






204


305 Trost B Science 1991 254 1471-1477





















Commun 2007 0 278-279

205








Commun 2014 50 1980-1982


Chem Soc 2013 136 777-782













206














v

Table of Contents

Abstract ii

Acknowledgments iv

Table of Contents v

List of Figures xi

List of Schemes xiv

List of Tables xix






12 Catalysis 4







1342 Alkenes 11

1343 Alkynes 11


1345 CO2 and SO2 13



vi




21 Introduction 19





















vii





23 Conclusions 56









31 Introduction 88










viii










33 Conclusions 113















ix




41 Introduction 132



















x





43 Conclusions 157

















52 Future Work 186

References 189

xi

List of Figures



















ppm [HB(C6F5)3]-) 33





xii






tol (c) 42














N(2) pyridine 54




xiii







104







136











xiv

List of Schemes








adduct at 195 K 9











(bottom) FLPs 15


borohydride FLP 16

xv


















= C6F5 221a and X = H 221b) 41





xvi






alcohols 90





hydrogenation 93












xvii





alkenylboranes 134




136





with [(Et2O)2H][B(C6F5)4] 141







alkynes 147


429 and 430 148

xviii













Ph2PH 155





187


xix

List of Tables














106





138


xx







xxi



α alpha


atm atmosphere

β beta


br broad


Bu butyl

C Celsius

ca circa

calcd calculated

CD cyclodextrin


C6H5Br bromobenzene



Cy cyclohexyl

δ chemical shift

xxii

deg degrees

d doublet

Da Dalton








eq equivalent(s)


Et ethyl

Et2O diethyl ether


γ gamma


g gram


GOF goodness of fit

xxiii

h hour





Hz Hertz



K Kelvin

kcal kilocalories

m meta

m multiplet


Me methyl


MHz megahertz

μL microliter

μmol micromole

mg milligram

min minute

xxiv

mL milliliter

mmol millimole


MS molecular sieves

nPr n-propyl





o ortho

π pi

p para



Ph phenyl

Ph2O diphenyl ether



q quartet

quint quintet

xxv


RT room temperature

σ sigma

s singlet

t triplet

tBu tert-butyl

THF tetrahydrofuran


TMS trimethylsilyl


tol toluene

wt weight

1














chemicals6-8















2






























3








rhombohedral36







industries35-36

112 Boron chemistry















4



















12 Catalysis



5


















131 Early discovery












6





















to boron73





7






under vacuum79-80













8



















9


adduct at 195 K














10










12)105









discussed







11




1342 Alkenes










1343 Alkynes








12

















13


(Scheme 110 right)



1345 CO2 and SO2










111 c)

14

Mes2P B(C6F5)2

EO2Mes2P B(C6F5)2

E O

O

R R

gt -20 degC- CO2

tBu3P B(C6F5)3EO2

80 degC- CO2

PB(C6F5)3E

O

O

tBu3


O

O

AlX3

CO2

b)

a)

c)
















15


(bottom) FLPs

















16

B(C6F5)2R2P

FF

F F

H

H

O

HPhB(C6F5)2R2P

FF

F F

H O

Ph

R = tBu Mes


borohydride FLP
















17



14 Scope of Thesis













reactions







18



















101002anie201503087





19



21 Introduction

211 Hydrogenation




















20





















RhPh3P

Ph3P Cl

PPh3

(a) (b) (c)

(d)

21






















(a) (b)

22


























23













HB(C6F5)2247









24























25






















26

















27







(Figure 25)



12 h

9 h

6 h

3 h

15 h

05 h

$

HB HA

28







(Figure 26)
















29




30



























the borane



31


























32


















33



ppm [HB(C6F5)3]-)
















45 degC

75 degC

95 degC

65 degC

115 degC

55 degC

85 degC

105 degC

34
















21

23

35





computations














36















37


















38










interaction121





















39















in Figure 213

40

HB(C6F5)3

NH

OCH3

B(C6F5)3

Ph

+ CH3OH

NH2

OCH3

Ph

NH2Ph

HB(C6F5)3

NHPh

OCH3

220

212

H2

B(C6F5)3

H2













41






(Scheme 212)


= C6F5 221a and X = H 221b)






42



tol (c)













a)

b)

c)

43

















44














acetonitrile)261









45

NH2

R

OCH3

110 oC

NHR

OCH3

NHR

OCH3

(F5C6)3B

+ H2

B(C6F5)3

H2

HB(C6F5)3

- H2HN

R

CH3OB(C6F5)3

+ H2

HB(C6F5)3

HNR

- CH3OH





















46










redelivery262







47














48













49

















explored


50
















a) b) c)

51








52






B(C6F5)3












53


























54



N(2) pyridine










NN NN

B

B(C6F5)3

(C6F5)3B H

- C6F5H H2

235

(C6F5)2





55






























56

23 Conclusions








rings





pyridines264
















57



























capabilities




58







0186 mmol 95)





















5071 H 258 N 211 Found C 5027 H 287 N 219

59



















252








as a white powder

60
























N 209




61








219












386 N 212










62


359 N 214










C 5014 H 348 N 209











4945 H 329 N 230





63







5011 H 350 N 216











5087 H 399 N 212











64



395 N 187













5358 H 323 N 195 Found C 5374 H 300 N 189









228 Found C 4686 H 247 N 232



65









4973 H 333 N 221






















66











299 N 208 Found C 4804 H 307 N 210














270 N 209 Found C 4793 H 282 N 203




67































68















610 μmol 89)









B(C6F5)4)




69









C6D5Br) δ -238 (d 1JB-H = 78 Hz BH)



















70
























solid





71

















N 223 Found C 4764 H 290 N 222




4660 H 247 N 211






72








(Et)






















73






























74































75




5026 H 330 N 209













N 198 Found C 5214 H 358 N 196











76













observed

















77


H 325 N 347 Found C 5611 H 313 N 321




















526 (CH2CHN) 308 (CH2) 245 (CH2) 229 (CH2) 188 (CH2)






Found C 5347 H 291 N 209

78


crystals)












(PiperidineCH2)













SRSRSR diastereomer



79




























2) and Fo




80







81



24 24rsquo 25


Formula wt 65526 64719 69532



a(Aring) 97241(8) 116228(4) 126342(6)

b(Aring) 147348(12) 181284(7) 181939(8)

c(Aring) 188022(15) 236578(9) 128612(6)

α(ordm) 9000 9000 9000

β(ordm) 98826(4) 9000 90269(2)

γ(ordm) 9000 9000 9000

V(Aring3) 26621(4) 49848(3) 29563(2)

Z 4 8 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1635 1725 1562

Abs coeff μ mm-1 0169 0179 0157


Rint 00336 00297 00369

Data used 4685 8773 5207


R (gt2σ) 00361 00315 00352

wR2 00898 00758 00947

GOF 1007 1021 1024

82


216a 218 219


Formula wt 67325 67123 71533



a(Aring) 97677(6) 104368(7) 18886(4)

b(Aring) 147079(11) 93382(7) 16050(3)

c(Aring) 190576(14) 273881(18) 19128(4)

α(ordm) 9000 9000 9000

β(ordm) 98934(2) 96910(3) 9000

γ(ordm) 9000 9000 9000

V(Aring3) 27046(3) 26499(3) 5798(2)

Z 4 4 8

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1653 1683 16388

Abs coeff μ mm-1 0174 0177 0163


Rint 00432 00404 00662

Data used 6164 4676 6654


R (gt2σ) 00522 00496 00687

wR2 01387 01462 01912

GOF 1032 1041 10743

83


220 222 (+05 CH2Cl2) 224 (+05 CH2Cl2)


Formula wt 74737 72573 79380



a(Aring) 173531(15) 17750(5) 109902(9)

b(Aring) 161365(15) 16032(4) 151213(11)

c(Aring) 227522(17) 20783(6) 194765(15)

α(ordm) 9000 9000 90

β(ordm) 9000 96910(3) 92062(3)

γ(ordm) 9000 9000 90

V(Aring3) 63710(9) 5914(3) 32346(4)

Z 8 8 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 15582 16278 1630

Abs coeff μ mm-1 0154 0250 0235


Rint 00406 01159 00306

Data used 7321 5198 5688


R (gt2σ) 00413 00811 00495

wR2 01112 02505 01363

GOF 10647 10628 0936

84


225 227 (+1 C5H12) 228


Formula wt 62721 141861 66727



a(Aring) 101339(5) 137416(4) 95967(15)

b(Aring) 112923(6) 119983(4) 108364(15)

c(Aring) 118209(6) 191036(7) 14143(2)

α(ordm) 98563(2) 9000 75929(5)

β(ordm) 109751(2) 109317(2) 80009(6)

γ(ordm) 94983(2) 9000 76629(5)

V(Aring3) 124520(11) 297240(17) 13772(4)

Z 2 2 2

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1673 1585 1609

Abs coeff μ mm-1 0176 0158 0235


Rint 00211 00246 00351

Data used 4357 5230 4743


R (gt2σ) 00371 00324 00546

wR2 00964 00816 01728

GOF 1044 1014 1028

85


229 (+05 C6H5Br) 230 231a


Formula wt 80784 66727 70733



a(Aring) 201550(11) 97752(4) 112914(4)

b(Aring) 133628(11) 120580(4) 183705(7)

c(Aring) 266328(18) 121120(5) 145648(5)

α(ordm) 9000 102296(2) 9000

β(ordm) 111905(6) 100079(2) 90480(2)

γ(ordm) 9000 90901(2) 9000

V(Aring3) 66551(8) 137127(9) 302105(19)

Z 8 2 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1613 1616 1555

Abs coeff μ mm-1 0749 0165 0155


Rint 00530 00245 00383

Data used 7644 4841 7630


R (gt2σ) 00651 00362 00778

wR2 01802 00971 02335

GOF 1037 1036 1007

86


231b (+05 C6H14) 233 234a (+1 CH2Cl2)


Formula wt 74840 80642 78621



a(Aring) 107250(6) 99895(4) 181314(6)

b(Aring) 112916(7) 115666(5) 135137(5)

c(Aring) 136756(8) 155410(6) 253612(9)

α(ordm) 70523(2) 9000 9000

β(ordm) 88868(2) 105054(2) 92594(2)

γ(ordm) 86934(2) 9000 9000

V(Aring3) 155914(16) 173405(12) 62077(4)

Z 2 2 8

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1594 1544 1677

Abs coeff μ mm-1 0155 0147 0327


Rint 00233 00381 00512

Data used 5479 8395 7383


R (gt2σ) 00371 00400 00816

wR2 01066 00893 02554

GOF 0926 1011 1024

87


234b 235 (+1 C4H8O +1 CH2Cl2)


Formula wt 70128 120323



a(Aring) 100455(5) 113115(7)

b(Aring) 118185(5) 117849(8)

c(Aring) 245940(11) 188035(12)

α(ordm) 9000 83850(3)

β(ordm) 96724(2) 88364(3)

γ(ordm) 9000 69766(3)

V(Aring3) 28998(2) 23383(3)

Z 4 2

Temp (K) 150(2) 150(2)

d(calc) gcm-3 1606 1709



Rint 00342 00265

Data used 5101 8235

Variables 433 712

R (gt2σ) 00438 00473

wR2 01153 01198

GOF 1012 1015

88



31 Introduction


























89



















(Scheme 32 b)275

90










33)277


alcohols



91

















molecular sieves

92
























93


hydrogenation





















94
















$ $ 12

11

10

9

8

7

6

5

4

3

2

1

95


















96




1 n-C3H7 n-C3H7 gt99 (91) gt99 70 52

2 Me iPr gt99 (76) gt99 44 42

3 Me CH2tBu gt99 gt99 (90) 22 14

4 Me n-C5H11 93 (85) 50 (43) 58 41

5 Me CH2Cl gt99 (85) gt99 91 82

6 Me Cy 77 - - -


8 Et n-C4H9 gt99 (87) 95 44 38

9 Et CH2iPr 40 47 - -



12 Me n-CH2CH2Ph gt99 (84) 69 58 24




16 -(CH2)5- 53 41 - -

17 -(2-iPr-5-Me)C5H8- gt99 (88) 89 47 45

18 Cy H 32 - - -





97





















98












mechanism






99

























100





















101










1 n-C3H7 n-C3H7 92

2 Me iPr 57

3 Me CH2Cl gt99

4 Me 2-butyl 53

5 Et iPr gt99

6 Et CH2iPr 40

7 Me Cy 18

8 Me Ph 20

9 Ph Ph 20

10 Et CH2Ph 25

11 Me n-CH2CH2Ph 25

12 -(CH2)5- 28

13 -(CH2)3CH=CH- 0

14 -(2-iPr-5-Me)C5H8- 62


102









R R1

OH

H

B(C6F5)3

R R1

O

+

B(C6F5)3

R R1

O NEt4

HB(C6F5)3

NEt4

B(C6F5)3

B(C6F5)3

R R1

O

05 H2

05 H2















103




























104



















a) b)

a)

b)

105










ca 70 ppm












106



1 Me iPr gt99 79 77 62 81 gt99

2 Me 2-butyl gt99 74 72 46 75 gt99

3 Me CH2tBu gt99 52 41 40 53 gt99


5 Me Cy gt99 81 62 31 64 gt99

6 Me n-C5H11 gt99 63 56 36 73 gt99

7 Et iPr gt99 75 75 69 80 gt99

8 Et n-C4H9 95 93 95 58 gt99 93

9 n-C3H7 n-C3H7 gt99 - - - - 92

10a Me Ph 30 13 15 10 27 trace

11 CH2CH2Cl Ph 54 - - - - 50

12 CF3 Ph 20 - - - - 20

13 Me o-CF3C6H4 trace - - - - 25

14 Me p-MeSO2C6H4 60 - - - - 97


16 Me CH2(o-FC6H4) 75 70 69 66 34 gt99

17 Me CH2(p-FC6H4) gt99 49 31 55 48 gt99


19 Et CH2Ph gt68 20 31 28 46 gt99

20 -(CH2)5- gt99 72 65 68 90 gt99


22 -(2-iPr-5-Me)C5H8- gt99 70 60 60 80 gt99

23 Cy H 10 - - - - 44

24 Ph2CH H 47 - - - - 86

25 PhCH(Me) H 20 - - - - 35


107












activity















108

















1 H Me CH2 92

2 CF3 Me CH2 95


cis 4

4 H iPr C(Me)2 75

109
















catalytically



1 H Ph 81

2 CH3O Ph 85

3 Br Ph 67

4 tBu Ph gt99

5 CH3 p-CH3C6H4 75

6 CF3 Ph 10

7 H o-CH3C6H4 20

110












and MS








111


















112












approaches62



0 mol

5 mol

10 mol

50 mol


113







in 17 - 25 yield259











33 Conclusions










114































115






protocol105






















116














observed















117































118










(80 eq)




















119


















0320 mmol 92)




247 (d 1JB-H = 91 Hz BH)









120



material ketone











GC-MS
















121






















alcohol products







122



= 731 [M-CH3] 551 [M-CH5O]













CH3] 790 [M-CH3]





1101 [M- H2O] 831 [M-C2H5O]






123


C2H5] 591 [M-C3H7]






691 [M-C2H7O] 590 [M-C4H9]






CH2iPr]





770 [M-C2H5O]







591[M-C7H7]



124





[M-C3H7O]























CH2F3O]

125




4029 min mz = 1001 [M] 821 [M-H2O]








951 [M-C3H9O] 811 [M-C4H12O]










561 [M-C2H6O] 450 [C2H5O]




126











C2H4Cl]






C6H4CF3) 1315 (C3) 1314 (C1) 1294 (C4) 1264 (C2) 1244 (C5) 1240 (CF3) 653


1720 [M-H2O] 1450 [M-C2H5O]










1811 [M-OH] 1671 [M-CH3O]

127





1211 [M-CH3] 1051 [M-CH3O]



alcohol products













1451 [M-C2H3] 1031 [M-CF3]







128














alcohol products











1211 [M-C6H5] 911 [M-C7H7O] 771 [M-C8H9O]





129


mz = 2480 [M+2] 2460 [M] 1671 [M-Br] 911 [M-C6H4Br]







CH3) 911 [C7H7]





[M] 1811 [M-CH3) 1661 [M-2(CH3)] 1051 [M-C7H7] 911 [M- C8H9]







1591 [M-C6H5] 911 [C7H7]


776 (m 2H o-Ph) 767 - 761 (m 3H m p-Ph) 759 - 754 (m 4H




GC-MS 12844 min mz = 1821 [M] 1671 [M-CH3]

130





15761 min mz = 1941 [M] 1791 [M-CH3] 1651 [M-C2H5]















2) and Fo










131



31 (+05 C6D5Br)


Formula wt 100893


Space group P2(1)c

a(Aring) 127865(6)

b(Aring) 199241(9)

c(Aring) 170110(7)

α(ordm) 9000

β(ordm) 1067440(10)

γ(ordm) 9000

V(Aring3) 41500(3)

Z 4

Temp (K) 150(2)

d(calc) gcm-3 1607



Rint 00368

Data used 9534

Variables 596

R (gt2σ) 00458

wR2 01145

GOF 1020

132



41 Introduction

411 Hydroamination






imines and enamines















133






















134










alkenylboranes

135




















136
















137















138


139
















(a) (b)

140



















141





















142



















143

















(Scheme 412)

(a) (b)

144


























145





146



(Table 42)


















products341






147


alkynes

















148


429 and 430






was not successful











149

















150





yield (Scheme 416)




















151


yield (Scheme 417)







1 H 0 68 434

2 H 1 66 435

3 F 1 72 436

4 CH3O 1 52 437








152







574 ppm (Figure 47)


the zwitterion 439








1H

1H31P

153




















(a) (b)

154




















155



Ph2PH









156









allenes147











157

43 Conclusions


























column prior to use




158

















experiments












159



product as a solid




-30 ordmC








1312 (p-Ph) 1310 (C7) 1307 (m-Ph) 1298 (Ph) 1293 (Ph) 1277 (C8) 1257 (C9) 1254 (o-





EZ ratio 71








CF) 1346 (C2) 1339 (C5) 1319 (C10) 1318 (C7) 1311 (C12) 1310 (C4) 1303 (C9) 1278

(C13) 1274 (C11) 1258 (C14) 1253 (C3 C8) 937 (C15) 619 (C6) 288 (Me) 208 (iPr)

160


296 N 165 Found 6037 H 317 N 173



EZ ratio 71









CD2Cl2) δ 1916 (C1) 1341 (C5) 1323 (C13) 1315 (C15) 1313 (C4) 1307 (C12) 1282 (C16)

1262 (C17) 1257 (C3) 1254 (C11) 699 (C6) 320 (C7) 291 (Me) 249 (C8) 244 (C9) (C2


C 6197 H 328 N 157 Found 6158 H 354 N 153












(C2) 1317 (C11 C14) 1311 (C9) 1309 (C13 C15) 1304 (C4 C10) 1296 (C8) 1294 (C16) 1278

B(C6F5)3

N1

2

3

45

7

8

9

10

14

1516

17

18

6

11

12

13

B(C6F5)3

N1

2

3

45

7

8 9

10

11 12

13

14

1617

1815

6

19

161



156 Found 6259 H 296 N 171




6106 H 262 N 142 EZ ratio 11


(m 2H H3) 730 (m 2H H4) 726 (m 2H H8) 717 (m 2H H15) 707







1364 1 (dm 1JC-F = 246 Hz CF) 1356 (C10) 1348 (C5) 1325 (C2) 1313 (C7) 1310 (C15)

1305(C8) 1297 (C4) 1292 (C3) 1278 (C16) 1274 (C14) 1269 (C11) 1257 (C17) 1255 (C9)

1155 (C12) 937 (C18) 557 (OMe) 283 (Me)


(m 2H H4) 730 (m 2H H3) 726 (m 2H H8) 717 (m 2H H12) 702 (m



1345 (C10) 1325 (C2) 1319 (C7) 1310 (C3) 1297 (C4) 1257 (C11) 1255








162



















Found 5885 H 366 N 154









163










129 Found C 6812 H 306 N 134














5702 H 323 N 180 Found 5667 H 330 N 179





164









1312 (C9) 1290 (C12) 1286 (C4) 1272 (C8) 1269 (C13) 1239 (C14) 593 (C6) 214 (Me)


















(560 mg 0733 mmol 99)

165








(C4) 1310 (C1) 1307 (C3) 1296 (C6) 1283 (C8) 1258 (C5) 1237 (C2) 941 (C9) 654 (tBu)


174











5318 H 304 N 194







solid

166












numerous attempts














Found 6059 H 281 N 197

167

























C21H20NO 30215449 Found 30215453

168



C6H5) 715 - 708 (m 6H o-C6H5 H3 H4) 706 -701 (m 1H H2) 700-



C6H5) 1390 (C1) 1364 (C6) 1309 (C5 C2) 1291 (m-C6H5) 1281 (C4) 1259 (C3) 1255 (o-


28615957 Found 28615986



H7) 771 - 768 (m 2H H2 H4) 752 (tm 3JH-H = 85 Hz 1H H9) 743




1371 (C1) 1341 (C6) 1319 (C5) 1292 (m-C6H5) 1288 (C7 C2) 1281 (C4) 1266 (C9) 1260








1293 (m-C6H5) 1286 (C3) 1285 (C4) 1276 (C2) 1243 (o-C6H5) 1228 (p-C6H5) 1082








169


1327 (C2) 1296 (C4) 1291 (m-C6H5) 1275 (C3) 1256 (o-C6H5) 1235 (p-C6H5) 1224 (C6)














(m 1H H4) 707 - 702 (m 5H H3 H8) 697 (m 1H H5) 691 (m






C20H15F3N 32611566 Found 32611576



= 36 Hz 4JH-H = 12 Hz 1H H2) 705 - 701 (m 4H H6) 695 - 689




170



31408200






(C1) 1446 (C=CH2) 1296 (m-C6H5) 1274 (C2) 1260 (C3) 1253 (C4) 1208 (o-C6H5) 1206


Found 2441166









(C5) 1306 (C4) 1294 (C2) 1292 (m-C6H5) 1291 (C7) 1273 (C9) 1271 (C8 C13) 1268 (C12)






H2) 788 (dm 3JH-H = 74 Hz 1H H7) 767- 762 (m 3H H9 H12




171


(C1) 1316 (C3) 1308 (C6) 1307 (C5) 1306 (C4) 1296 (C2) 1291 (C7) 1274 (C9) 1272 (C8


Found 40815576



H6) 701 (m 4H H8) 697- 691 (m 5H H4 H9) 516 (s 1H =CH2)






for C20H15F3N 32611566 Found 32611485
















172





34013065
















CD2Cl2) δ 728 - 720 (m 2H H2 H5) 708 - 700 (m 2H H3 H4)







173


C20H17F3N 32813131 Found 32813189
























174





















0103 mmol 54)









NB(C6F5)3

4

3

2

1

175










(427 mg 0265 mmol 68)









(451 mg 0257 mmol 66)








176




1H H4) 135 (m 1H H1) 121 (m 1H H3) 113 (m 2H H23) 102 (m 1H H2)






















177




























178








5314 H 432





















179





























180










2) and Fo


















181



41 47 48


Formula wt 88546 108572 77939



a(Aring) 91451(8) 120520(8) 99293(9)

b(Aring) 20583(2) 122120(8) 115709(11)

c(Aring) 20738(2) 184965(12) 168258(15)

α(ordm) 9000 103236(4) 75826(4)

β(ordm) 96295(4) 104461(4) 77700(4)

γ(ordm) 9000 104447(4) 65591(4)

V(Aring3) 38800(6) 24264(3) 16930(3)

Z 4 2 2

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1516 1482 1529

Abs coeff μ mm-1 0138 0126 0146


Rint 00444 00308 00308

Data used 8910 11131 5899


R (gt2σ) 00420 00532 00488

wR2 00964 01380 01380

GOF 1018 1028 1026

182


49 410

(+05 C5H12)

413

(+1 C2H4Cl2)


Formula wt 86350 85145 98643



a(Aring) 174202(13) 113739(5) 138815(4)

b(Aring) 135941(10) 115489(6) 242842(7)

c(Aring) 174144(13) 158094(7) 146750(4)

α(ordm) 9000 92979(2) 9000

β(ordm) 118149(3) 97298(2) 1108840(10)

γ(ordm) 9000 116865(3) 9000

V(Aring3) 36362(5) 182343(15) 46220(2)

Z 4 2 4

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1577 1536 1418

Abs coeff μ mm-1 0256 0143 0236


Rint 00299 00352 00437

Data used 6409 8342 8147


R (gt2σ) 00570 00504 00687

wR2 01537 01410 02122

GOF 1045 1021 1092

183


414

(+05 CH2Cl2 +1 C5H12)

432

(+05 C5H12) 439


Formula wt 96404 72131 110070



a(Aring) 309455(12) 80774(6) 117846(13)

b(Aring) 193567(7) 117730(8) 159017(19)

c(Aring) 182668(6) 158569(11) 16349(2)

α(ordm) 9000 79707(3) 108194(4)

β(ordm) 123002(2) 86387(3) 107588(4)

γ(ordm) 9000 87902(3) 104551(4)

V(Aring3) 91764(6) 148021(18) 25646(5)

Z 8 2 2

Temp (K) 150(2) 150(2) 150(2)

d(calc) gcm-3 1397 1620 1425

Abs coeff μ mm-1 0179 0160 0179


Rint 00476 00352 00284

Data used 8097 6615 9023


R (gt2σ) 00716 00560 00339

wR2 02417 01703 00880

GOF 1047 1096 1019

184


440 442





a(Aring) 329294(17) 114236(2)

b(Aring) 118317(6) 151074(3)

c(Aring) 206088(10) 192749(4)

α(ordm) 9000 9000

β(ordm) 107535(5) 93553(1)

γ(ordm) 9000 9000

V(Aring3) 76563(7) 332009(11)

Z 8 4

Temp (K) 150(2) 223(2)

d(calc) gcm-3 1479 1449



Rint 00316 0055

Data used 8776 6697

Variables 517 456

R (gt2σ) 00365 00672

wR2 01017 01623

GOF 1021 1048

185


51 Thesis Summary




























186




















also described

52 Future Work









187
























188







189

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197












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hydrogenation and hydroamination reactions using boron ......ii hydrogenation and hydroamination...

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