Advices For Studying Organic Chemistry

R Br

R Cl

I R I (+ Cl− or Br−)

−

3. Inversion of configuration in SN2 reactions:

NC − + C Br NCC

CH 3

H CH

2 CH 3

(R)-2-Bromobutane

SN 2

(inversion)

CH 3

CHH

2 CH 3

+ Br−

(S)-2-Methylbutanenitrile

6.15A THE UNREACTIVITY OF VINYLIC AND PHENYL HALIDES

1. Vinylic halides and phenyl halides are generally unreactive in SN1 or SN 1
   reactions.

1. Vinylic and phenyl cations are highly unstable and do not form readily.


2. The C–X bond of a vinylic or phenyl halide is stronger than that of an alkyl
   halide and the electrons of the double bond or benzene ring repel the approach of
   a nucleophile from the back side.

CC

X

X

A vinylic halide Phenyl halide

The Chemistry of....

Biological Methylation: A Biological Nucleophilic Substitution Reaction
−O 2 CCHCH 2 CH 2 SCH 3
NH 3 +

Methionine

Nicotine

N+

CH 3

H 3 C CH 2 CH 2 OH

CH 3

Adrenaline Choline

HO

HO

CHCH 2 NHCH 3

OH

N

N CH^3