Esterification of carboxylic acids with alkyl halides using electroreduction

Abstract

Esterification of carboxylic acids with alkyl halides using electroreduction has been investigated. The reaction of carboxylic acids, such as benzoic acid, 3-phenylpropanoic acid, nonanoic acid, cinnamic acid, and 1-naphthoic acid, under electrochemical reduction conditions followed by the addition of alkyl halides afforded the corresponding esters in moderate to good yields. The reactions proceeded via the SN2 mechanism of the alkyl halide, with the carboxylate ion bearing the ammonium ion as the counter cation, which was generated and accumulated from the carboxylic acid. The generation of the carboxylate ion intermediate is essential, and it appears to have high reactivity because the counter cation of the carboxylate ion intermediate is an ammonium ion.