Synthesis of benzimidazole fused poly-heterocycles via oxidant free Cu-catalyzed dehydrogenative C–N coupling and photophysical studies

Abstract

A unique example of Cu-catalysed synthesis of benzimidazole fused poly-heterocycles via intramolecular C–N coupling reaction has been reported. The method highlights the potential of Cu-catalysed reactions via C–N bond formation in the absence of ligand, oxidant, and additives under inert atmosphere. The mechanistic studies indicate that the reaction is facilitated by the involvement of a benzimidazole N-atom and releases H₂ gas, resulting in the synthesis of benzimidazole-fused coupling products in good yield. The versatility of the approach is demonstrated by the synthesis of diverse fused compounds, which exhibit high fluorescence activity and good quantum yield.