Photocatalytic Transfer Imino-Phosphorothiolation of Alkenes

We report a metal-free, oxidant-free energy-transfer photocatalytic 1,2-iminophosphorothiolation of alkenes using a rationally designed O-iminophosphorothioate as a bifunctional reagent. In contrast to conventional P(O)SH-based approaches─limited to monofunctionalization─this strategy enables the simultaneous incorporation of an imino group and a -S-P(O)(OR)₂ moiety with 100% atom economy. Under triplet energy transfer catalysis, the reagent undergoes homolytic cleavage of the N-O bond, followed by resonance-driven delocalization of the initially formed O-centered radical to a more stable S-centered phosphorothioate radical, delivering diverse β-iminophosphorothioates in good yields with excellent regioselectivity. Notably, challenging substrates such as trifluoromethyl alkenes, gem-difluoroalkenes, and allene also participate efficiently. The protocol is operationally simple, scalable, and represents a sustainable, step-economical platform for dual heteroatom difunctionalization.