Hydrosilylation of Aldehydes and Ketones Catalyzed by an N-Heterocyclic Carbene-Nickel Hydride Complex under Mild Conditions
Résumé
Half-sandwich N-heterocyclic carbene (NHC)-nickel complexes of the general formula [Ni(NHC)ClCp†] (Cp†=Cp, Cp*) efficiently catalyze the hydrosilylation of aldehydes and ketones at room temperature in the presence of a catalytic amount of sodium triethylborohydride and thus join the fairly exclusive club of well-defined nickel(II) catalyst precursors for the hydrosilylation of carbonyl functionalities. Of notable interest is the isolation of an intermediate nickel hydride complex that proved to be the real catalyst precursor.