天津大学高等有机化学课件8

Chapter 12 Molecular Rearrangements I Classification of Rearrangement Reactions( ) II Nucleophilic Rearrangement ( ) 1 Wagner-Meerwein rearrangement( )2 3 4 5 Pinacolic Rearrangement ( ) α-ethandione Rearrangement ( ) Beckmann Rearrangement ( ) Baeyer-Villiger Rearrangement ( ) PRODUCER:张文勤

III Electrophilic Rearrangement ( )1 favorskii Rearrangement 2 Stevens Rearrangement 3 Wittig Rearrangement 4 Fries Rearrangement

IV Radical Rearrangement

I Classification of Rearrangement ReactionsMolecular Rearrangements:it refers those reactions in which the carbon skeleton or the position of functional group changed.CH3CH2CH=CH2 H3PO4 CH3CH=CHCH3

CH3

CH3 C CH2OH CH3

H+ H2O

CH3C=CHCH3 CH3

CH2NH2 CH2NH2

HNO3

CH2OH

CH2OH

CH3

CH3 CH3 C C CH3 OH OH

H CH3 H2O

+

CH3 O C C CH3 CH3

Usually the rearrangement was classified by theelectron property of the moving group, such asNucleophilic rearrangement, Electrophilic rearrangement, Radical rearrangement, etc.

Nucleophilic rearrangementH+ CH3CH2CH2CH2OH

CH3CH2CH2CH2OH2

H CH3CH2CHCH2CH3CH2CH+CH3 H+

H2O

CH3CH=CHCH3

Electrophilic rearrangementPh CH2 O CH3 PhLi C6H6

Li+ Ph CH O CH3

CH3 - + H2O Ph CH O LiCl Cl C CH=CH2 Cl

CH3 Ph CH OHCl Cl C CH CH2Br Cl

Radical rearrangementBr

Br Cl Cl Br2 Cl C CH CH2Br Cl C CH CH2Br Cl Cl

II Nucleophilic Rearrangement1 Wagner-Meerwein rearrangement ( Carbon cation rearrangement )CH3 CH3 C CH2OH CH3 H+

CH3

CH3 C CH2OH2 CH3Cl-

H2OCl C CH2CH3 CH3

CH3

CH3 C CH2 CH3

CH3

CH3 C CH2CH3 CH3

H+

CH3C=CHCH3 CH3

Cl

Cl

-

Cl

Cl

OH H+

+

+

CH3

CH3 CH3 C CHCH3 SN1 CH3 C CHCH3 CH3 Br CH3 CH3 C CHCH3 CH3 CH3

Product

Stable cationCH3 CH3 C CHPh CH3 Br SN1 CH3 CH3 C CHPh CH3CH3 C CHPh CH3 CH3

Stable cationCH3O > R3C > > Cl

Product> CH2=CH >H

> R2CH > CH3

CH3

CH3 CH3 HNO2 CH3 C CH2 C CH2OH N2 CH3 CH3CH3 C CH2CH3 H2O H+ CH3NH2 HNO2 N2

CH3

OH C CH2CH3 CH3

CH2NH2

CH2

+ +

H2O H+ H+

CH2OH

OH

CH2

CH2NH2 HNO2 N2

CH2+

H2O H+

CH2OH 32%

H+

H+ 2%HNO2 NH2 N2

+

H2O H++ +

OH 58%H2O H+

H2O H+

CH2=CHCH2OH

2 Pinacolic RearrangementCH3 CH3 CH3 CH3 H+ CH3 C C CH3 C C CH3 H2O OH +OH2 OH OHCH3 CH3 C C CH3 OH CH3+

CH3

CH3 CH3 C C CH3 +OH CH3

H

+

CH3

CH3 C C CH3 O CH3

The stable cation formed superior + Ph C CH H Ph2C CH22 2+

OH OHPh2CH CH +OH+

OH

Ph2CH CH H O

Phenyl group move firstPhHC CHPh OH OH H+

PhHC+

CHPh OH

Ph2CH CH +OH

H

+

Ph2CH CH O

Phenyl with electron donor group move first

(p MeOC6H4)2C CPh2 OH OH

H

+

(p MeOC6H4)2C CPh 72% Ph O p MeOC6H4C O CPh2 28% C6H4OMe p

Under HNO2, the amino alcohol rearranges as that of pinacol

NH2 HNO2 OH CH2NH2 OH HNO2

CHO

O

3 α-Ethandione RearrangementO O NaOH Ph C C Ph EtOH COONa H O+ 3 OHO OH Ph C C O Ph

COOH Ph2C OH

Ph2C

O OH O O OH Ph C C O Ph C C Ph Ph OH O Ph C C O Ph

-

O OH O O OH R C C OR C C ROH OR C C O R

O OH R C C O R

-

R

O O C C

OH

-

O OH C C O

O OH C O

-

OH O C O

-