Highly practical oxidation of benzylic alcohol in continuous-flow system with metal-free catalyst

Oxidation of benzylic alcohol to ketone or aldehyde is one of the most challenging reactions in terms of green chemistry. We report herein that employing H2O2, catalytic amount of Br− and acid in continuous-flow system to realize oxidation of benzylic alcohols with broad substrate scope and high selectivity. More importantly, no over oxidation to acid was obtained and it showed higher selectivity to 2° hydroxyl groups rather than 1°.

Graphical abstractOxidation of benzylic alcohol to ketone or aldehyde is one of the most challenging reactions in terms of green chemistry. We report herein that the oxidation of benzylic alcohols with broad substrate scope and high selectivity is realized by employing H2O2, catalytic amount of Br− and acid in continuous-flow system. More importantly, no over oxidation to acid was obtained and it showed higher selectivity to 2° hydroxyl groups rather than 1°.Download high-res image (69KB)Download full-size image