Abstract
Get selective! A selective oxidation of 1,2‐diols to α‐hydroxyketones catalyzed by organotin compounds has been developed (see scheme). Invaluable chemo‐ and stereoselectivity were found in the reaction. The catalytic system has been achieved by electrochemical and chemical oxidation.magnified image
Electrochemical oxidation of 1,2‐diols with a catalytic amount of an organotin compound and a bromide ion as mediators has been developed. Various cyclic and acyclic 1,2‐diols were oxidized into the corresponding α‐hydroxyketones in good to excellent yields without CC bond cleavage. Also, oxidation with the use of chemical oxidants was accomplished in the presence of a catalytic amount of an organotin compound. These reactions could discriminate 1,2‐diols from isolated hydoxyl groups or 1,3‐diols. In the case of a conformationally restricted cyclic 1,2‐diol, the axial hydroxyl group was oxidized exclusively. Mono‐, di‐, and trialkylated tin compounds were examined as mediators and dialkylated tin compounds showed higher catalytic activity than mono‐ and trisubstituted ones. Me~2~SnCl~2~ was found to be the most suitable mediator for the selective oxidation.