Haller‐Bauer Cleavage

Abstract

Haller–Bauer cleavage is the base induced cleavage of a carbon‐carbon bond of a nonenolizable ketone to give a carboxylic acid derivative and a neutral fragment in which the carbonyl group is replaced by hydrogen. It has also reported that this reaction overwhelmingly involves a carbanion and the mode of cleavage depends on the relative stability of the carbanions involved. Some exceptions have also been represented which result in reverse cleavage because of the steric interaction. The metal cation of used bases are found to affects this reaction. This reaction has been extended to use potassium t ‐butoxide or N ‐alkylamines and N , N ‐dialkylamines to induce the cleavage. This reaction has been used in the preparation of tertiary carboxamides, tertiary alcohols, and debenzoylation.