Hidden Boron Catalysis: Nucleophile-Promoted Decomposition of HBpin

Abstract

Simple nucleophiles with structural similarities to known hydroboration catalysts can readily mediate the formation of BH₃ and borohydride species from pinacolborane (HBpin). Alkyne and alkene hydroboration reactions were successfully mediated by nucleophiles through BH₃ generation, with BH₃-catalyzed hydroboration found to dominate catalysis. NMR spectroscopy and kinetic analyses showed that the nucleophiles NaO^<i>t</i>Bu, Na[N(SiMe₃)₂], ^<i>n</i>Bu₂Mg, and ^<i>n</i>BuLi only promoted the formation of BH₃ and were not "true" hydroboration catalysts.