Efficient Synthesis of Mandel Acetates by Electrochemical Carboxylation of Benzal Diacetates. Issue 16 (5th April 2019) - Senboku, Hisanori
Abstract: Efficient synthesis of mandel acetate, 2‐acetoxy‐2‐phenylacetic acid, from benzaldehyde was successfully performed in two steps using electrochemical carboxylation of benzal diacetate as a key step. When benzal diacetate, readily prepared from benzaldehyde and acetic anhydride in one step, in DMF containing 0.1 M Bu4 NBF4 was electrolyzed in the presence of carbon dioxide using an undivided cell equipped with a platinum plate cathode and a magnesium rod anode under constant current conditions, reductive cleavage of the C‐OAc bond followed by capture of carbon dioxide took place efficiently at the benzylic position to give mandel acetate in good to high yields. Wide scope, high yields and the use of carbon dioxide as a carbon source of the carboxyl group would provide novel environmentally‐benign synthesis of mandelic acid derivatives. Abstract : CO2 fixation : Efficient synthesis of mandel acetates, 2‐acetoxy‐2‐arylacetic acids, is successfully carried out by electrochemical carboxylation of benzal diacetates. The present electrochemical synthesis has a wide scope and provides mandel acetates in good to excellent yields without any hazardous/severe reagents/conditions even by using carbon dioxide as a carbon source of the carboxyl group, and is promising as a conventional, powerful, and environmentally‐benign synthetic process.