Reduction and Rearrangement of a Boron(I) Carbonyl Complex.

The one‐electron reduction of a cyclic (alkyl)(amino)carbene (CAAC)‐stabilized arylborylene carbonyl complex yields a dimeric borylketyl radical anion, resulting from an intramolecular aryl migration to the CO carbon atom. Computational analyses support the existence of a [(CAAC)B(CO)Ar].− radical anion intermediate. Further reduction leads to a highly nucleophilic dianionic (boraneylidene)methanolate. [ABSTRACT FROM AUTHOR]