CHEMISTRY

1. GENERATION OF
ENOLATES USING
NUCLEOPHILIC
BASES
NAME :- SIDDHESH MAHENDRA KAREKAR
ROLL NO. :- 02
M.Sc.-1
SEM-2

2. ENOLATES
Enolates are formed when a base
removes a proton on the 𝛼-carbon to a
carbonyl group.

3. NUCLEOPHILIC BASES

4. ROLE OF BASES IN
FORMATION OF ENOLATES
 The common bases used to form
enolates are shown below

5. GENERATION OF ENOLATES
FROM NUCLEOPHILIC BASES
The reaction in which the anion
(enolates) is derived by removal of
proton from the α-carbon atom
attached to carbonyl group

6. SOME IMPORTANT
NUCLEOPHILIC BASES
Metal Hydrides:
•examples: NaH, KH
•amorphous solids
•very basic
(conjugate acid is 𝐻2)
Alkyl Lithiums:
•examples: MeLi,
nBuLi, sBuLi, tBuLi
•very basic (conjugate
acid is an alkane)
•good nucleophiles →
side reactions possible

7. Amides:
•examples:
NaNH2, LiNH2,
KNH2
•strongly basic
(conjugate acid
is ammonia)
Alkoxide
Bases:
•examples:
MeONa, tBuOK
•weaker than
amine bases
(conjugate acid
is an alcohol)
•deprotonation
is generally
reversible

8. EXAMPLE

9. APPLICATION
•Robinson Annulation reaction
•Michael addition reaction

10. • Dieckmann cyclisation
• Alkylation of 𝛽-dicarbonyl dianions
Mostly now prefer base combination of NaH &
BuLi or 2LDA to generate the dianion
• Malonic ester synthesis

11. REFERENCE
 Organic chemistry, J. claydens, N. Greeves, S.
Warren & P. Wothers.
 Organic Synthesis, Michael B. Smith
 Advanced Organic Chemistry: Reactions &
mechanism, L.G. Wade