Rhodium-Catalyzed Selective Chalcogenation of B(4)-H of o-Carboranes

A rhodium-catalyzed universal protocol for selective chalcogenation of B(4)-H of o-carboranes with diaryl diselenides, diaryl disulfides, and diphenyl ditelluride has been developed for the first time. A series of B(4)-Se/S/Te-o-carborane derivatives decorated with various kinds of active groups have been synthesized with excellent yields and regioselectivity. Based on control experiments, a plausible mechanism involving radical and direct oxidative addition process is proposed. This work would be an important reference for the design of new reactions for the chalcogenation of boron clusters.