neighbouring group participation, organic chemistry,M.Sc. 2

1. S.I.E.S COLLEGE OF ARTS, SCIENCE AND
COMMERCE
ORGANIC CHEMISTRY
M.SC. PART 2
SEMESTER 3
2015-2016
NAME :-JOYNA VARGHESE
TOPIC :-UNIT 1.2 NEIGHBOURING GROUP
PARTICIPATION.

2. CONTENTS
INTRODUCTION.
WHAT IS NGP?
POINTS TO REMEMBER.
MECHANISM.
STEREOCHEMISTRY.
OTHER EXAMPLES.

3. INTRODUCTION
Nucleophilic substitution reaction.
Unusual behaviour.
Symphoric effect.
Substrate and reagent are both parts
of the same molecule.
Enhanced rate with an unexpected
stereochemistry.

4. WHAT IS NGP?
Definition:-
The interaction of a reaction
centre with a lone pair of electrons in an atom
or the electrons present in a sigma bond or pi
bond.
Anchimeric assistance.

5. POINTS TO REMEMBER.
Adjacent carbon atom.
SN2 mechanism.
New cyclic reaction intermediate.
Nucleophile must be in trans position
to the leaving group.

6. MECHANISM
Two SN2 substitutions take place.
STEP 1:- Attack of the internal nucleophile.
STEP 2:- Substitution of external nucleophile.

7. STEREOCHEMISTRY
Unexpected behaviour 1:- Retention
of configuration.
Unexpected behaviour 2:- First
order reaction.

8. OTHER EXAMPLES.
1. NGP BY PI BONDS
2. NGP BY AROMATIC RINGS.

9. BIBLIOGRAPHY
ORGANIC CHEMISTRY [6TH
EDITION]
-MORRISON AND BOYD.
ORGANIC CHEMISTRY [2ND
EDITION]
-MICHEAL B. SMITH.

10. THANK YOU