Visible-Light-Driven Radical Amination/Cyclization of Arylethynyl Quinazolinones To Access Sulfonaminated Quinolino[2,1‑b]quinazolines

A visible-light-driven radical amination/cyclization of arylethynyl quinazolin-4(3H)-ones was developed using N-aminopyridinium salts as sulfonamino radical precursors. A series of sulfonaminated quinolino[2,1-b]quinazolines were successfully synthesized under oxidant- and additive-free conditions. The transformation features a broad substrate scope, good to excellent yields, and mild reaction conditions. Notably, the amination–cyclization reaction could proceed smoothly under natural sunlight irradiation.