Hidden Boron Catalysis: Nucleophile-Promoted Decomposition of HBpin

Simple nucleophiles with structural similarities to known hydroboration catalysts can readily mediate the formation of BH 3 and borohydride species from pinacolborane (HBpin). Alkyne and alkene hydroboration reactions were successfully mediated by nucleophiles through BH 3 generation, with BH 3 -catalyzed hydroboration found to dominate catalysis. NMR spectroscopy and kinetic analyses showed that the nucleophiles NaO t Bu, Na[N(SiMe 3 ) 2 ], n Bu 2 Mg, and n BuLi only promoted the formation of BH 3 and were not “true” hydroboration catalysts.