An Improved Electrochemical Method for the Synthesis of Some Benzofuran Derivatives

Abstract

Electrochemical oxidation of catechol and some 3-substituted catechols (1a—c) has been studied in the presence of 2-chloro-5,5-dimethyl-1,3-cyclohexanedione (3) in aqueous solution using cyclic voltammetry and controlled-potential coulometry. The results indicate that the quinones derived from catechols (1a—c) participate in a Michael addition reaction with 2-chloro-5,5-dimethyl-1,3-cyclohexanedione (3) with consumption of only two electrons per molecule of (1a—c) to from the corresponding benzoforans (10a—c). The electrochemical synthesis of benzofurans has been successfully performed at a carbon rod electrode and in an undivided cell with high yields and purity.