Visible‐Light‐Induced Cascade Cyclization: Accessing Acylated 4H‐3,1‐Benzoxazines from Benzoquinone and Alkynylanilides

A novel visible‐light‐induced cascade cyclization strategy for the synthesis of 4 H ‐3,1‐benzoxazines from benzoquinone and alkynylanilides is described. This transition metal‐ and oxidant‐free method utilizes direct photoexcitation of benzoquinone to its triplet state, eliminating the need for additional photosensitizers. The process generates tetrasubstituted carbon‐centered 4 H ‐3,1‐benzoxazine compounds bearing both acyl and phenolic substituents. The method exhibits broad substrate compatibility, high atom economy, and operational simplicity, providing an environmentally benign route to diverse 4 H ‐3,1‐benzoxazine derivatives—privileged scaffolds in medicinal chemistry.