Synthesis of Carbocyclic and Heterocyclic Fused Quinolines by Cascade Radical Annulations of Unsaturated N-Aryl Thiocarbamates, Thioamides, and Thioureas

Tandem radical cyclizations of suitably substituted N-aryl thiocarbamates, thioamides, and thioureas are induced by exposure to tris(trimethylsilyl)silane (TTMSH) and UV light and provide furoquinolines, isofuroquinolines, cyclopentaquinolines, indoloquinolines, and related ring systems. The intermediacy of an α-thioalkylamino radical, which is the synthetic equivalent of an imidoyl radical, is invoked.