Ester Condensation: bKeto Esters

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Ester Condensation b-Keto Esters
(E.g., b-Dicarbonyl Compounds Aceto acetates
and Malonates)
Claisen Ester Condensation (Intermolecular) and
Dieckmann Cyclization (Intramolecular) Reaction
Nucleophilic Substitution Reaction Involving An
Ester Enolate (Nucleophile) and An Ester
(Electrophile).
Overall Process
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Claisen Ester Condensation Self condensation of
Ethyl Acetate
STEP 1 FORMATION OF ESTER-ENOLATE
ANION
Nucleophilic site
a-Carbanion is resonance stabilized
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Claisen Ester Condensation Self condensation of
Ethyl Acetate
STEP 2. NUCLEOPHILIC SUBSTITUTION
Deprotonation by the base drives equilibrium
forward formation of stable carbanion
NUCLEOPHILIC ADDITION
ELIMINATION
NUCLEOPHILIC SUBSTITUTION
Protonation (2nd STEP in reaction) completes the
reaction.