Visible Light Photoredox Catalyzed Cascade Cyclizations of α-Bromochalcones or α-Bromocinnamates with Heteroarenes

Vinyl radicals were generated from -bromochalcones or -bromocinnamate ethyl ester under visible light photoredox catalyzed conditions via an oxidative quenching cycle of the iridium complex [Ir{dF(CF3)ppy}(2)(dtbbpy)]PF6 and subjected to cascade cyclizations with heteroarenes entailing two consecutive CC bond formations and three CH activations. The process is amenable to furans, benzofurans, pyrroles, and indoles, giving rise to a broad variety of novel polycyclic frameworks in high yields under mild and environmentally benign reaction conditions.