Direct and Regioselective Palladium(II)-Catalyzed B(4)-H Monoacyloxylation and B(4,5)-H Diacetoxylation of o -Carborane Acids with Phenyliodonium Dicarboxylates.

A direct B(4)-H monoacyloxylation via a Pd-catalyzed regioselective B(4)-H activation of o -carborane acids with phenyliodonium dicarboxylates was developed, and a series of B(4)-H monoacyloxylated o -carboranes decorated with active groups were synthesized with moderate to good yields as well as excellent selectivity. In addition, a direct B(4,5)-H diacetoxylation from o -carborane acids with phenyliodonium diacetate was demonstrated.