Pure and Applied Chemistry

Abstract: 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 sp² 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 β-boration and diboration reactions.