Visible-Light-Promoted Iminyl-Radical Formation from Acyl Oximes: A Unified Approach to Pyridines, Quinolines, and Phenanthridines

A unified strategy involving visible-light-induced iminyl-radical formation has been established for the construction of pyridines, quinolines, and phenanthridines from acyl oximes. With fac[Ir(ppy)(3)] as a photoredox catalyst, the acyl oximes were converted by 1e(-) reduction into iminyl radical intermediates, which then underwent intramolecular homolytic aromatic substitution (HAS) to give the N-containing arenes. These reactions proceeded with a broad range of substrates at room temperature in high yield. This strategy of visible-lightinduced iminyl-radical formation was successfully applied to a five-step concise synthesis of benzo[c]-phenanthridine alkaloids.