Tetrahedron Letters Vol. 54, Issue 34, 2013

Contents

COMMUNICATIONS

A mild and catalyst-free aromatization using dihydroxylcyclohexanone derivatives as phenyl sources:a new approach to anilines

pp 4505–4508

Jun Luo*, Enwei Ji, Jingyuan Ye, Runze Wu, Lei Qiu

+

R1NH

R2

NR2

R1

O O

O

BPh

R NH2

4A MS

DCM, RT

- metal-free- strong base-free- mild reaction conditions- yield up to 99%

NH R

or or

Organocatalytic asymmetric sulfa-Michael addition of thiols to trans-3,3,3-trifluoropropenyl phenyl sulfone pp 4509–4511

Xin Fang, Xiu-Qin Dong, Yuan-Yuan Liu, Chun-Jiang Wang*

F3CSO2Ph

13 examples,82-99% yield,

36-84% ee

II-c(1 mol %)

+RSH

CH2Cl2, -20 °C F3C ∗SO2Ph

SR

NHN

NH

S PhPh

OH

II-c

The first asymmetric sulfa-Michael addition of thiols to trans-3,3,3-trifluoropropenyl phenyl sulfone for the construction of a unique stereogeniccenter bearing a trifluoromethyl group and a sulfur atom has been achieved in high yields and moderate to good enantioselectivities with 1 mol %bifunctional amine–thiourea catalyst.

13H-Quinazolino[3,4-a]quinazolin-13-one: synthesis and structural revision pp 4512–4514

Somepalli Venkateswarlu*, Meka Satyanarayana, Pasupuleti Ravikiran, Anupoju Vijayakumar

NH2

NH2

O

N

N

N

O

N

N N

O

NH2

CN

Publishedstructure

+ HC(OEt)3

Revised

4 steps

53% overallyield

X

4497

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Highly facile approach to the formal total synthesis of camptothecin pp 4515–4517

Changqing Wei, Zhihui Jiang, Shujuan Tian, Dazhi Zhang*

N

O

O

O

NOH

N ONN OMeN

OH

OO

Camptothecin (1a)1211

Ref. 7dMsCl

CHCl3,

-10 oC, 1 h85%

Expanding the scope of silane-mediated hydrodehalogenation reactions pp 4518–4521

Gary M. Noonan*, Barry R. Hayter, Andrew D. Campbell, Timothy W. Gorman, Benjamin E. Partridge, Gill M. Lamont

Pd-ligand (5% Pd)

Et3N (2 eq.)Et3SiH (5 eq.)

Cl/Br

R

HR

Effective for previously unreactivesubstrates (R = OH, CO2H)

andChemoselective hydrodehalogenation

conditions (R = NO2, olefin, O-Bn)

Platinum-catalysed synthesis of trichloroamidines pp 4522–4523

Jay J. Dunsford, Jason E. Camp*

Synthesis of 5-substituted 3-mercapto-1,2,4-triazoles via Suzuki–Miyaura reaction pp 4524–4525

Sarmite Katkevica, Pavlo Salun, Aigars Jirgensons*

BnN

NN

SBn

X

BnN

NN

SBn

R

NH

NN

SH

R

RB(OH)2 or RBPin

K2CO3, cat. Pd(PPh3)4

AlCl3

X-Br, I 21 examplesyields 43-99%

18 examplesyields 75-96%

R = Ar, vinyl

4498 Contents / Tetrahedron Letters 54 (2013) 4497–4503

Asymmetric synthesis of aminopyrimidine and cyclic guanidine amino acids pp 4526–4528

Vicki D. Möschwitzer, Benson M. Kariuki, James E. Redman*

Catalyst controlled regioselective Suzuki cross-coupling of 2-(4-bromophenyl)-5-chloropyrazine pp 4529–4532

Christopher P. Ashcroft*, Steven J. Fussell*, Katie Wilford

N

N Cl

Br NH

NBO

O

NN

N

Br

N

NH

N

N

N Cl

N

NH

N

Pd catalyst, ligand, base, solvent

+

BocBoc Boc

The Suzuki cross-coupling between 2-(4-bromophenyl)-5-chloropyrazine and a range of aryl boronic acids has been investigated. Theregioselectivity of the reaction can be switched between the aryl bromide and pyrazinyl chloride positions by changing the ligand associatedwith the palladium catalyst. Xantphos has shown excellent selectivity for the pyrazinyl chloride, with most other ligands showing preferentialselectivity for the aryl bromide.

An easy access to asymmetrically substituted oligoethylene glycols from 18-crown-6 pp 4533–4535

Polina I. Abronina, Alexander I. Zinin, Anna V. Orlova, Sergey L. Sedinkin, Leonid O. Kononov*

OO

O

OOO

N3 OO

OO

OOH

H2NO

OOH

O

n

n = 4, 5

Indirect N-vinylation of indoles via isomerisation of N-allyl derivatives: synthesis of (±)-debromoarborescidine B pp 4536–4539

Gordana Tasic, Milena Simic, Stanimir Popovic, Suren Husinec, Veselin Maslak, Vladimir Savic*

N

NHCOOEt

N

NHCOOEt

t-BuOK, DMSO

56% 4 : 1 Z/E

NaH, DMSO

60% Z only

N

NHCOOEtGrubbs II(5 mol%)

88%

1,2-DCE

Contents / Tetrahedron Letters 54 (2013) 4497–4503 4499

NiCl2Æ6H2O/NaBH4 in methanol: a mild and efficient strategy for chemoselective deallylation/debenzylation ofaryl ethers

pp 4540–4543

Mangilal Chouhan, Kapil Kumar, Ratnesh Sharma, Vikas Grover, Vipin A. Nair*

Protection-free, short, and stereoselective synthesis of ieodomycin A and B pp 4544–4546

N. Nageswara Rao, H. M. Meshram*

OH OH

O

O

Ieodomycin A

O

OH

O

Ieodomycin B

OH

N

O

S

S

9

OH

Total 7 Steps

Cincholenines A and B, two unprecedented quinoline alkaloids from Cinchona ledgeriana pp 4547–4550

Gui-Guang Cheng, Yu Zhang, Xiang-Hai Cai, Mei-Fen Bao, Ji Gu, Yan Li, Ning Liu, Ya-Ping Liu*, Xiao-Dong Luo*

N

O

N

1N

O

N

H3CO

2

O O

Xinshengin, the first altenusin with tetracyclic skeleton core from Phialophora spp. pp 4551–4554

Feng Ye, Guo-Dong Chen, Jun-Wei He, Xiao-Xia Li, Xiang Sun, Liang-Dong Guo, Yan Li, Hao Gao*

4500 Contents / Tetrahedron Letters 54 (2013) 4497–4503

Casuarines A and B, Lycopodium alkaloids from Lycopodium casuarinoides pp 4555–4557

Fei Liu, Xing-De Wu, Juan He, Xu Deng, Li-Yan Peng, Huai-Rong Luo, Qin-Shi Zhao*

21

Copper-catalyzed cross-coupling reaction of a-sulfur-substituted alkylstannanes with acid chlorides pp 4558–4560

Hirotaka Kagoshima*, Naoshi Takahashi

R2

SR1

SnnBu3

CuF2 (1 mol%)+

O

R3 Cl R3 R2O

SR11,4-dioxane

102 °C

up to 94%

Synthesis of (±)-lecanindole D pp 4561–4563

Akiko Asanuma, Masaru Enomoto, Tomohiro Nagasawa, Shigefumi Kuwahara*

O

O(±)-Wieland Miescher

ketone

H

HO

H

OHOHN

H(±)-lecanindole DO

O

A stereoselective method for the construction of the C80–O–C600 ether of nigricanoside-A: synthesis of simple modelsfor the C20 lipid chain/galactosyl glycerol segment

pp 4564–4567

Naoto Kinashi, Kenshu Fujiwara*, Takayuki Tsunoda, Ryo Katoono, Hidetoshi Kawai, Takanori Suzuki

O

OMe

OH

MeOH

OH

O

OMe

O

MeO

OHO

HOOH

O OHOH

Nigricanoside-A Dimethyl Ester

8'

6''

1'

1' '2' '

R

S/R(8'S,2'''R)-& (8'R,2'''R)-

C20 lipid chain/galactosyl glycerol

segment models

Julia-Kocienski Olefination

Ireland-Claisen Rearrangement

Contents / Tetrahedron Letters 54 (2013) 4497–4503 4501

LL-Valine derived benzimidazole based bis-urea in enantioselective fluorescence sensing of LL-tartrate pp 4568–4573

Kumaresh Ghosh*, Tanmay Sarkar

N NO O

N N

NN

NN

H HH H

ab( )

( )77

1

The bis-urea 1 is found to act as enantioselective chemosensor for tartrate. The sensor shows greater fluorescence response for LL-tartrate in DMSO.The enantiomeric fluorescence difference ratio (ef) has been determined to be 2.46.

Desymmetrization of a-diimines: synthesis of new 3-(diaziridin-3-yl)oxaziridines pp 4574–4576

Emanuele Aresu, Laura Carroccia, Stefania Fioravanti*, Lucio Pellacani

N

HN

HN

EtO2CR

R

N

HN

HN

EtO2CR

RO

N

HN

HN

EtO2CR

RO

NsONHCO2Et

N

HN

HR

R

H2O/CH2Cl2

desymmetrization reaction

+

major minor

aziridinationreaction

epoxidationreaction

CH2Cl2CaOm-CPBA

Regioselective bromination of tetronic acid-derived c-lactones and metal-catalyzed post-functionalization:an efficient access to new c-ylidenetetronate derivatives

pp 4577–4581

Shinya Iikawa, Nicolas Chopin, Guillaume Pilet, Jean-Philippe Bouillon, Maurice Médebielle*

OOR2

OR1

Br

OOBr

OR1

OOR2

OR1BrMetal-catalyzedcross coupling

reactions OOR4

OR1

R2

R3

Tetronicacid

or R2

Bisamides as ligands in Suzuki coupling reactions catalyzed by palladium pp 4582–4584

Daniel P. da Costa, Sabrina M. Nobre*

4502 Contents / Tetrahedron Letters 54 (2013) 4497–4503

Synthesis and fluorescence of xanthone amino acids pp 4585–4587

Christian Hoppmann*, Ulrike Alexiev, Elisabeth Irran, Karola Rück-Braun*

OTHER CONTENTS

Corrigendum to ‘‘An effective one-pot conversion of acid chlorides to aldehydes and ketones’’ [Tetrahedron Lett. 54(2013), 3199–3203]

p 4588

Jae Kyo Park, Won Kyu Shin, Duk Keun An*

Corrigendum to ‘‘Two concise total syntheses of the wasabi phytoalexin methyl 1-methoxyindole-3-carboxylate’’[Tetrahedron Lett. 54 (2013) 3124–3126]

p 4589

Bing Li, John D. Williams, Norton P. Peet*

*Corresponding authorSupplementary data available via SciVerse ScienceDirect

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ISSN 0040-4039

Contents / Tetrahedron Letters 54 (2013) 4497–4503 4503