Iridium(III)-Catalyzed B(4)-Acylmethylation and B(3,5)-Diacylmethylation from o -Carboranes and Sulfoxonium Ylides.

An iridium(III)-catalyzed regioselective acylmethylation of the cage B(4)-H bond in o -carborane acids with sulfoxonium ylides is demonstrated through B(4)-H activation in ethanol under very mild conditions, affording a number of B(4)-acylmethylated o -carboranes. Additionally, the selective sequential B(4)- and B(6)-acylmethylation reactions finally gave B(3,5)-diacylmethylated o -carboranes in one pot.