Green and Highly Efficient Synthesis of New Bis-benzofurans via Electrochemical Methods under ECECCC Mechanism

Oxidation of hydroquinone (1a) has been studied in the presence of methyl cyanoacetate (3a) and ethyl cyanoacetate (3b) as nucleophile in phosphate buffer solution (0.2 M, pH 7) mixed with ethanol as a green solvent (80:20 v:v) using cyclic voltammetry and coulometry, under constant potential. The obtained results indicated that p-quinone derived from electro-oxidation of hydroquinone (1a), participated in 1,4-Michael addition reactions with cyanoacetate derivatives (3a-3b) via ECECCC mechanism (E:electrochemical and C: chemical). In the present study, new benzofuran derivatives were synthesized in good yields and high purity using a facial, one-pot and environmental electrochemical method by 3 carbon electrodes in an undivided cell, without any chemical reagent and hazardous solvents.