Electrochemically promoted arylation of iodoaromatics

Abstract

The electrochemical reduction of iodobenzene, 4-iodobenzonitrile and 4-iodonitrobenzene in DMF:benzene (2:8), in one-pot reaction and at room temperature, leads to cross-coupling products, biphenyl, 4-phenylbenzonitrile and 4-phenylnitrobenzene in low to moderate yields. The proposed mechanism involves the formation of the aryl anion that is consistent with the number electrons transferred. The aryl anion reacts with benzene to form a σH-complex that is oxidized to the cross-coupling product in the reaction conditions. In identical conditions, 4-iodotoluene and 4-iodoanisole forms toluene and anisole, showing that electron donating groups in the iodoarene disfavour cross-coupling reaction.