Nucleophilic boron strikes back

It has been demonstrated that the interaction of a simple Lewis base with tetraalkoxydiboranes generates an unusual nucleophilic character in one of the boryl moieties. The interaction of amines, N-heterocyclic carbenes (NHCs), and alkoxides with a diboron reagent results in the formation of a Lewis acid-base adduct, in which the formally intact sp(2) boryl moiety becomes nucleophilic. We describe in this work the application of this new type of nucleophilic boron synthon in the selective preparation of organoboranes through beta-boration and diboration reactions.