Copper-catalyzed four-component radical cascade cyclization of enynes to assemble trifluoromethyl- and carbamoyloxyl-substituted pyrrolo[1,2-a]benzimidazoles

Abstract

A copper-catalyzed multicomponent radical domino reaction of 1-allyl-2-ethynylbenzoimidazoles with Togni's reagent, amines and CO₂ was successfully developed. This method provides a convenient and efficient approach to access valuable trifluoromethyl- and carbamoyloxyl-substituted ring-fused benzimidazoles in satisfactory yields with good functional group tolerance and high regio- and stereo-selectivity. Additionally, it enables the conversion and utilization of CO₂ under mild conditions.