Scope and mechanism of nitrile dihydroboration mediated by a β-diketiminate manganese hydride catalyst

The manganese hydride dimer, [( 2,6-iPr 2 Ph BDI)Mn(μ-H)] 2 , was found to mediate nitrile dihydroboration, rendering it the first manganese catalyst for this transformation. Stoichiometric experiments revealed that benzonitrile insertion affords [( 2,6-iPr 2 Ph BDI)Mn(μ-NCHC 6 H 5 )] 2 en route to N , N -diborylamine formation. Density functional theory calculations reveal the precise mechanism and demonstrate that catalysis is promoted by monomeric species. Nitrile insertion allows for manganese-catalyzed nitrile dihydroboration at 80 °C.