Visible-Light-Driven Photoredox-Catalyzed [4 + 2] Annulation of Unsaturated α-Bromocarbonyls with α-Substituted Styrenes.

Cyclohexenes are ubiquitous structural motifs in pharmaceuticals and natural products, yet their efficient and sustainable synthesis from simple precursors remains a challenge. Herein, we report a visible-light-driven photoredox-catalyzed intermolecular [4 + 2] annulation that enables rapid, regioselective access to multisubstituted cyclohexenes from readily accessible unsaturated α-bromocarbonyls with α-substituted styrenes. The mild, operationally simple conditions accommodate diverse functional groups and enable gram-scale synthesis, versatile product elaboration, and access to a complex bicyclo[2.2.2]octene framework.