Directing‐Group‐Assisted Markovnikov Hydroximation of Styrenes Enabled by Photoredox/Cobalt Dual‐Catalysis

By the combination of acridinium salt as a photocatalyst and cobaloxime complex as a co‐catalyst, a simple and mild approach has been developed for the directing‐group‐assisted Markovnikov‐selective hydroximation of styrenes under visible‐light irradiation. Herein, the directing‐group on styrenes plays an important role for this transformation. Although the substrate scope seems to be limited, such an approach features excellent regioselectivity and high atom economy. In contrast with previous methodologies, this photoredox/cobalt dual‐catalytic system is operationally simple, and avoids the use of any other sacrificial reagents.