Electrochemical regioselective reduction of α-keto amides with methanol as a hydrogen source

An efficient method for converting α-keto amides to α-hydroxy amides has been developed by chemoselective hydrogenation reduction. Utilizing electricity and methanol as both the hydrogen source and solvent, KI and bases participate in the reaction to obtain various α-hydroxy amides (44 cases, up to 100%). The reaction is operationally simple (room temperature, air environment, and undivided cell with constant current electrolysis), avoids the use of traditional reducing agents, is free from metal or transition-metal catalysts, and does not require organic ligands. CV experiments and control studies show that the reduction of α-keto amides proceeds <i>via</i> a parallel paired electrolysis strategy instead of a sacrificial metal anode strategy. The substrate was reduced at the cathode, while KI underwent oxidative reactions at the anode by easily losing electrons. Moreover, this reaction can tolerate high current densities and can be scaled up to the gram scale.