15.26:

Esters to β-Ketoesters: Claisen Condensation Overview

JoVE Core
Organic Chemistry
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JoVE Core Organic Chemistry
Esters to β-Ketoesters: Claisen Condensation Overview

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01:24 min

April 30, 2023

Regular Claisen condensation is a base-promoted reaction involving identical esters with two α hydrogens, condensing to produce β-ketoesters. It is a nucleophilic acyl substitution reaction wherein one of the ester molecules, upon deprotonation by the base, forms a nucleophilic enolate ion, while the other molecule serves as an electrophile.

Figure1

The condensation reaction requires specific nonaqueous bases, such as alkoxide, which must be similar to the alkoxy group of the ester molecule. The use of different alkoxide ions often leads to the transesterification product. Also, the use of hydroxide bases is avoided as they result in irreversible hydrolysis of the esters to carboxylate ions.

Figure2