Anodic oxidation of organic compounds based on the cation exchange reaction between KBF₄ and solid-supported acids

We have developed a novel electrolytic system for anodic oxidation of organic compounds based on the cation exchange reaction between potassium tetrafluoroborate (KBF₄) and solid-supported acids. It was clarified by cyclic voltammetry as well as preparative electrolyses that hydrogen tetrafluoroborate (HBF₄) derived from the cation exchange reaction acts as a supporting electrolyte in MeCN. On the basis of the electrolytic system, anodic oxidation of 1,2,4-trimethoxybenzene was carried out to provide the corresponding homocoupling product in quantitative yield. Furthermore, anodic oxidation of benzyl alcohols having not only electron-donating but also electron-withdrawing groups at the para position was successfully achieved by optimizing the reaction conditions.