Bromodimethylsulfonium bromide as a potential candidate for photocatalytic selective oxidation of benzylic alcohols using oxygen and visible light

Selective photooxidation of different benzylic alcohols has been carried out in the presence of molecular oxygen and a catalytic amount of bromodimethylsulfonium bromide (BDMS) under visible light irradiation. The above method was found to be efficient for the oxidation of primary and secondary benzylic alcohols into their corresponding aldehydes and ketones with excellent product yield. Unlike other studies, the advantages of this study are the metal-free green protocol, utilization of a household compact fluorescent lamp (CFL) lamp as the visible light source, and the high selectivity of the reaction. A mechanistic study infers that the carbonyl compound obtained by the process possesses an oxygen atom which comes from molecular oxygen. From the study, we propose that the conversion of the benzylic alcohol to its corresponding aldehyde could be following a peroxy radical intermediate. The first-hand results revealed the photocatalytic potential of BDMS in general and its capability for selective alcohol oxidation, in particular.