Visible-Light-Driven [3 + 2] Annulation of N-Substituted Aromatic Amines with Nitriles: An Approach to Benzimidazoles

A visible-light-driven [3 + 2] annulation of N-substituted aromatic amines with nitriles has been developed, providing efficient access to benzimidazoles. The reaction proceeds under mild conditions with a broad substrate scope and good functional group tolerance. Mechanistic studies support a photoredox-catalyzed radical pathway.