The simple system of fixing CO2 to synthesize benzimidazolones at atmospheric pressure

A simple chemical fixation of CO2 at atmospheric pressure to make valuable benzimidazolones derivates via the o-phenylene-diamines carbonylation reaction catalyzed by DBU/S was developed. Different reaction conditions were examined and optimized. A series of benzimidazolones derivatives were synthesized using NMP as solvent at 413K with excellent yields (80–94%). Various substrates were employed and the results suggested the wide application of our method. The quantum mechanics calculations demonstrated that the complexation of DBU with sulfur significantly enhanced the reaction. This protocol rovides a novel approach of fixing CO2 at atmospheric pressure into a series of 2-benzimidazolones derivates.