Photoredox-Enabled Difluoromethylation Cyclization and Quinoxalin-2(1 H )-one Integration: Access to gem -Difluoro-Quinolines

Abstract Herein, a novel protocol for the photoredox-enabled intramolecular difluoromethylation cyclization and intermolecular domino quinoxalin-2(1H)-one integration is established. This version allows facile access to structurally diverse gem-difluoro-quinolines. A wide substrate scope, wide functional group compatibility, bioactive molecule decoration, and gram-scale amplification attest to the utility of this protocol. A radical cyclization mechanism is proposed on the basis of radical inhibition experiments, a visible-light irradiation on–off test, AQE calculations, and Stern–Volmer fluorescence quenching experiments.