We disclose herein an efficient regioselective B­(3,4)–H activation via a ligand strategy, affording B(3)-monoacyloxylated and B­(3,4)-diacyloxylated o-carboranes. The identification of amino acid and phosphoric acid ligands is crucial for the success of B(3)-mono- and B­(3,4)-diacyloxylation, respectively. This ligand approach is compatible with a broad range of carboxylic acids. The functionalization of complex drug molecules is demonstrated. Other acyloxyl sources, including sodium benzoate, benzoic anhydride, and iodobenzene diacetate, are also tolerated.

Efficient Pd-catalyzed oxidative dehydrogenative cross coupling of B–H/B–H bonds of two pyridyl o-carboranes has been developed, leading to the preparation of B(3)–B(6′) heterocoupled and B(3)–B(6′) homocoupled biscarboranes with a broad substrate scope at room temperature.