Recent Advances in Transition Metal-Catalyzed Selective B-H Functionalization of o-Carboranes

Carboranes are a class of carbon-boron molecular clusters, possessing extraordinary characteristics including three-dimensional aromaticity conjugated by σ-bonds, icosahedral geometry and inherent robustness. They are finding growing applications as valuable building blocks in boron neutron capture therapy agents, pharmacophores, nanomaterials, optoelectronic, organometallic/coordination chemistry and more. Therefore, the effective and controlled functionalization of carboranes has attracted enormous research interests, particularly in regio- and enantio-selective cage BH derivatization among ten chemically similar BH vertices of o-carboranes. Only in the recent few years, significant progress has been made in transition metal catalyzed vertex-specific BH functionalization. This review summarizes recent advances in this research realm.