Green and One-Pot Electrochemical Synthesis of New Benzofurans Based on an ECC Mechanism

Abstract

The electrochemical oxidation of quinizarine has been studied in the presence of methyl cyanoacetate and ethyl cyanoacetate acting as a nucleophile in acetate buffer solution mixed with ethanol (30/70 v/v) using cyclic voltammetry and controlled-potential coulometry methods. The results revealed that anthracene-1,4,9,10-tetraone derived from the electro-oxidation of quinizarin participates in 1,4-Michael addition reactions with cyanoacetate derivatives. The adducts formed convert to the corresponding benzofuran derivatives through an ECC (Electrochemical, Chemical, Chemical reaction) mechanism. In the present study, benzofuran derivatives were synthesised in good yields using controlled potential electro-oxidation at three graphite electrode in an undivided cell under mild conditions.