Reduction of a dihydroboryl cation to a boryl anion and its air-stable, neutral hydroboryl radical through hydrogen shuttling

A doubly cyclic (alkyl)(amino)carbene-stabilised dihydroboronium cation undergoes fully reversible 2e⁻ reduction to a stable hydroboryl anion via B-to-C hydrogen migration. Subsequent 1e⁻ oxidation yields a bench-stable neutral hydroboryl radical.