Wacker-type oxidation of styrenes with Markovnikov selectivity using copper as a site-selective sequential photooxidant–photoreductant†

Abstract

We report a palladium-free Wacker-type oxidation of styrenes using CuCl₂/KBr as the catalyst and trichloroisocyanuric acid as a stoichiometric chlorine radical source. The reaction protocol is compatible with diverse functional groups, affording selectively acetophenones. The mechanistic analysis revealed that a site-selective sequential Cu^II-photooxidation/Cu^I-photoreduction of the intermediary chlorohydrin is the key to the success of this transformation.