Electrochemistry facilitates the chemoselectivity of benzylic alcohol oxidations mediated by flavin-based photoredox catalysis

The use of oxygen for catalyst regeneration in photoredox catalysis causes selectivity problems, due to the generation of reactive oxygen species causing over- and side-oxidations. Herein, we present a system using electrochemical regeneration of a flavin catalyst working under inert conditions, which allows the chemoselective oxidation of primary and secondary benzylic alcohols to carbonyl compounds without unwanted overoxidation to carboxylic acids. The method also tolerates other oxidation-sensitive groups such as methyl, methylsulfanyl, or pinacolboryl groups.