Visible-light-promoted regioselective silylation/cyclization of cyclopropanol-tethered sulfonamides for the synthesis of silyl-substituted benzazepines.

A visible-light-promoted regioselective silylative cascade cyclization of cyclopropanol-tethered benzenesulfonamides with hydrosilanes is reported. This transformation, enabled by Ir photoredox catalysis and PhI(OAc)2, proceeds smoothly under blue LED irradiation at room temperature, providing efficient access to silyl-substituted benzazepine derivatives. The reaction features mild conditions, broad substrate scope, good functional group tolerance, and compatibility with diverse hydrosilanes. Scale-up synthesis and further product derivatizations highlight the synthetic utility of this method.