Visible Light–Promoted Radical Cascade Bicyclization to Access Partially Saturated Pyrrolo[2,3‐ b ]Pyridines

Abstract A visible light–promoted cascade [2+2+1] bicyclization reaction of N ‐cyanamide alkenes and activated alkyl bromides has been successfully established. This reaction exhibits mild conditions, metal‐free characteristics, and excellent atom‐ and step‐economy, along with environmental friendliness. It demonstrates broad substrate tolerance and scalability to gram‐scale synthesis, underscoring its potential for practical applications. Preliminary mechanistic studies suggest that the reaction proceeds through a photoinduced single‐electron transfer (SET) process and a 1,5‐hydrogen atom transfer (HAT) process mediated by an iminyl radical.