Continuous-Flow Electrochemical Oxidation of Alkylarenes and Diarylmethanes to Aromatic Ketones Using Water under Catalyst-, Mediator-, and Additive-Free Conditions

A single-pass continuous-flow electrochemical oxidation method has been developed for the synthesis of aromatic ketones from alkylarenes and diarylmethanes by utilizing 0.5 equiv of LiClO₄ as the supporting electrolyte and water as a safe oxygen source in a mixture of acetonitrile and water. The reactions were conducted in a commercially available undivided flow microreactor equipped with a graphite plate anode and a platinum plate cathode, providing a broad range of aromatic ketones within a short residence time of 25 min. No additional electrocatalysts, redox mediators, additives, or chemical oxidants were required, highlighting the environmental friendliness and sustainability of this continuous-flow electrochemical protocol. Furthermore, the synthetic utility of this approach has been demonstrated by the gram-scale syntheses of a Celestolide derivative, a Fenofibrate derivative, and an anthraquinone.