Rh(III)-Catalyzed One-Pot Synthesis of Benzimidazoquinazolines via C-H Amidation-Cyclization of N-LG-2-phenylbenzoimidazoles

An efficient protocol to synthesize substituted benzo[4,5]imidazo[1,2-c]quinazolines starting from N-LG-2-phenylbenzoimidazole and dioxazolones catalyzed by Rh(III) or Ir(III) has been developed. Various substituted benzo[4,5]imidazo[1,2-c]quinazolines could be easily provided in up to 99% yield. A large range of substrates and functional groups are compatible for this transformation. This method features low catalyst loading, acid-free conditions, and low solvent consumption.