Construction of Unsymmetrical B─B Bond via Carboranyl Radical

ABSTRACT This work describes a general method for constructing unsymmetrical B(cage)–B single bond at room temperature via boron‐centered carboranyl radicals. The approach enables the efficient utilization of both boron atoms from B 2 cat 2 with very high yields. The key hypercoordinate boron radical intermediates are generated through a visible‐light‐driven Ni(I)/Ni(II) redox cycle employing zinc as the reducing agent. These radicals react directly with B 2 cat 2 to form B─B bond, which can subsequently undergo further derivatizations including boronic ester formation and hydroxylation.