Copper-photocatalyzed atom transfer radical addition of thiosulfonates to alkenes†

The Atom Transfer Radical Addition (ATRA) reaction provides a powerful strategy for constructing valuable molecules in an atom- and step-economic manner by simultaneously incorporating two functional groups into unsaturated C–C bonds. However, their introduction remains a challenging topic among the synthetic research community due to the need for expensive and complex catalytic systems, poor regioselectivity, and limited substrate scope. Herein, we present a visible-light-induced, copper-catalyzed ATRA protocol for the thiosulfonylation of alkenes with thiosulfonates under mild conditions. The notable aspect of this protocol is the avoidance of noble-metal-based catalysts while maintaining compatibility with styrene, unactivated alkenes, and alkynes for ATRA reactions involving various thiosulfonates. Mechanistic studies indicated that the reactions take place via metallaphotoredox catalysis.