Photoredox‐Catalyzed Decarboxylation/Transamidation Cascade Toward γ‐Lactams From α,β‐Unsaturated N ‐Acylindoles and α‐Amino Acids

A visible‐light‐induced redox‐neutral protocol is developed for the synthesis of diverse N ‐aryl γ‐lactams via a decarboxylative radical addition/intramolecular transamidation cascade from α,β‐unsaturated N ‐acylindoles and α‐amino acids. The N ‐acylindole motif serves dual roles as an activated acyl donor and a traceless indole leaving group, driving the key transamidation step thermodynamically. Notably, the released indole can be recovered and reused for substrate synthesis, thus improving the atom economy of the process. The reaction features broad substrate scope and mild conditions. This method provides a practical and green complement to conventional γ‐lactam synthesis.