MODERN ORGANIC SYNTHESISMODERN ORGANIC SYNTHESISMr. Anand S Burange,Institute Of Chemical Technology, Matunga , Mumbai-400019E-mail: asgburange@gmail.com

O

OHHO

OH

O

OOH

HO OH

O

OOH

OH

OH

O

OO

OH

OH

HO

OOH

OHHO

O

OOH

HO

HO

O

HO

O

HO

H

N

Sir, Robert Boyle ; First

man who independently

started working in

scientific field of

chemicals now termed as

Chemistry.

In 1828, when F. Wohler

accidently got urea in the

laboratory, from that day

Organic Chemistry came

into an existence

2NET/SET guidance lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

WHAT IS A CHEMICAL REACTION?WHAT IS A CHEMICAL REACTION?

Chemical reaction is an effective interaction between two or more molecules/atoms /ions leading to the formation of new compound(s).

A B

3NET/SET guidance lecture under UGC merged scheme at Patkar College, Goregaon,

Mumbai

SynthesisOrganic synthesis is a construction of complex organic compounds by a series of chemical reactions.

There are two main areas of research in the field of organic synthesis, namely total synthesis and methodology.

HO

H

H

H

4NET/SET guidance lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

Three main keys in organic synthesis

O

HO

O

HO

H

N

H

O

H

O

5NET/SET guidance lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

Functional group InterconversionsFunctional group Interconversions

O

O

O

OH

O

O

O

i

ii

iii

iv

v

vi

vii

I. (CH3 )2S+CH2- (DMSO,NaH,Me3S+ )

II. NaBH4/ EtOH

III. Zn-Hg/ HCl OR N2H4 / KOH

IV. SeO2

V. (a) NaBH4/ EtOH (b) H+ /Heat

VI. NaOH

VII. LDA, PhSeBr/H2O2

6NET/SET guidance lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

i

ii

iii

iv

v

vi

vii

CHO

CH2OH

COOH

O

OH

O

OH

CHO

NO2

i. NaOH (Cannizaro) OR H- donor reductant

ii. K2Cr2O7/H+ OR KMnO4/H

+

iii. CH2N2 OR (a) KMnO4/H+ (b) 2eq.

MeLi

iv. (a) KMnO4/H+ (b) SOCl2 (c) EtMgBr

v. RhCl(Pph3)3 : Wilkinson’s catalyst

vi. NaCN/EtOH

vii. Conc. HNO3/Conc. H2SO4

NET/SET guidance lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

i

ii

iii

iv

v

vi

vii

O

OH

O

O

O

O

OH

i. CH2I2, Zn(Cu)/ Et2O

ii. m-CPBA (Bartlett Mechanism)

iii. SeO2

iv. (a) SeO2 (b) MnO2

v. (a) SeO2 (b) MnO2 (c) -CH2 –SOMe2

vi. (a) SeO2 (b) MnO2 (c)H2O2/OH-

vii. (a) HBr (b) Mg /Dry ether (C) Ph-CHO

NET/SET guidance lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

i

ii

iii

iv

v

vi

vii

O

O

O

O

CHO

OH

HO

O

CO2Et

NH

O

i. m-CPBA

ii. CH2N2

iii. (a) Cl-CH2-COOEt/Me3CONa (b) H3O+ OR Ph3P=CH-OMe

iv. (a)Mg-Hg/ TiCl4 (b) H2O

v. (a) H2N-OH (b) H+

vi. (a)Pyrrolidine/TsOH (b) CO (OEt)2

vii. Ph3P=CH2

NET/SET guidance lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

Some Functional group Interconversions for practiceSome Functional group Interconversions for practice

H

O HO

i. 9-BBNii. Ethanolamine

OHNH2 i. Cl-PO(OEt)2/NaH

ii. NaNH2/NH3 (Via Benzyne)

OH

OH

i. Hg(OAc)2 /H2Oii. NaBH4/ OH-

i. B2H6/ solventii. H2O2/ OH-

NET/SET guidance lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

Asymmetric SynthesisAsymmetric Synthesis

OH

OH

OH

OH

OsO4 OR KMnO4

I2/AgOAc (dry) OR (a)m-CPBA (b) Hydrolysis

Alkene dihydroxylation

O

O

NaBH4

NaBH4

CeCl3

OH

OH

Reduction

NET/SET guidance lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

Luche’s Reduction

CO2Me

CO2Me

Stereospecific cycloaddition reactions

CO2Me

CO2Me

MeO2C

CO2Me

CO2Me

CO2Me

[4+2] cycloaddition reactions takes place in presence of heat

NET/SET guidance lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

O O

Epoxidation

m-CPBAi. NBSii. OH-

NET/SET guidance lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

GETTING SLEEPYNOW IT’S TIME TO MOVE YOUR HEAD UP & DOWN

!!ANTI PERIPLANAR RELATIONSHIP!!

iPr

Cl

MeRO-

?

iPr

Cl

Me

H

iPr

Cl

Me

HRO-

iPr Me

NET/SET guidance lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

OH

TsO(CH3)3O-

NH2OH

HNO2

OH

NH2

HNO2

NH2OH

HNO2

O

CHO

O

O

DON’T GET FRUSTRATED!!!

NET/SET guidance lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

Retrosynthesis – thinking backwards from relatively complex molecules to simpler ones – the disconnection approach originated by E.J. Corey (Nobel Prize 1990)

Terms involvedTarget Molecule (TM) The compound we wish to prepare

Retrosynthetic Analysis  The process of WORKING BACKWARDS from the TM in order to devise a suitable synthetic route.

Readily Available Starting Materials (RASM)  cheap, commercially available compounds.

Synthon  An idealised fragment, usually a cation or anion, resulting from a disconnection.

Synthetic Equivalent The actual compounds used to function as synthons.

Functional Group Interconversion (FGI) The process of writing one functional group for another to help synthetic planning and to help

disconnection.  

O

Target MoleculeO

C-C dix O

Synthons

OO

Cl+ AlCl3 Friedel Craft's reagent

Chemical Equivalents (C.E.)O

Cl+ AlCl3

O

NR2

NO2O2N

CF3

NR2

NO2O2N

CF3

C-N dix

Cl

NO2O2N

CF3

C-N dix

Cl

CF3

TM (Target Molecule)

NET/SET guidance lecture under UGC merged scheme at Patkar College, Goregaon, Mumbai

Cl

CF3

1. Conc.HNO3/conc.H2SO4

2. R2NH/Base

NR2

NO2O2N

CF3