Silyl Radical-Mediated Carbocyclization of Acrylamide-/Vinyl Sulfonamide-Attached Alkylidenecyclopropanes <i>via</i> Photoredox Catalysis with a Catalytic Amount of Silane Reagent

A silyl radical-mediated carbocyclization of acrylamide-/vinyl sulfonamide-attached alkylidenecyclopropanes via photoredox catalysis with a catalytic amount of silane reagent is reported in this paper. With this protocol, a highly efficient synthesis for the construction of lactam- and sultam-containing polycyclic derivatives in 63–95% yields was achieved with a broad substrate scope. A reasonable reaction mechanism was proposed based on control experiments, where the catalytic amount of tris­(trimethylsilyl)­silane was used as the radical-based reagent.