Stobbe condensation
The Stobbe condensation entails the reaction of an aldehyde or ketone with an ester of succinic acid to generate alkylidene succinic acid or related derivatives. The reaction consumes one equivalent of metal alkoxide. Commonly, diethylsuccinate is a component of the reaction. The usual product is salt of the half-ester. The Stobbe condensation is named after its discoverer,, whose work involved the sodium ethoxide-induced condensation of acetone and diethyl succinate.
An example is the reaction of benzophenone with diethyl succinate:
A reaction mechanism that explains the formation of both an ester group and a carboxylic acid group is centered on a lactone intermediate :