Recent progress in 1,3,2-diazaborole chemistry

Abstract The-chemistry of 1,3,2-diazaboroles has undergone rapid development in the last three decades. This includes diazaborolide anions, which as powerful nucleophiles allow the transfer of boryl units onto electrophilic systems. As strong σ-donors bulky diazaborolyl ligands are capable of stabilizing electron – deficient species such as silylenes and their heavier congeners. 2-Bromo-1,3,2-diazaboroles are valuable electrophiles, serving as precursors for a wide variety of highly functionalized systems such as 2-phosphaethynolato-diazaborole and its isomeric 2-phosphaketenyl-diazaborole. The first type of compounds was successfully employed for the synthesis of various organophosphorus heterocycles with boryl substituents, whereas the latter group of compounds serve as convenient transfer reagents of diazaborolylphosphinidenes. Diazaboroles are also interesting for material chemistry as the incorporation of the ring motif BN2C2 into extended organic π-systems gives rise to modified or completely new material properties.