Carbonyl and ester C-O bond hydrosilylation using κ4-diimine nickel catalysts.

摘要: The synthesis of alkylphosphine-substituted α-diimine (DI) ligands and their subsequent addition to Ni(COD)2 allowed for the preparation (iPr2PPrDI)Ni (tBu2PPrDI)Ni. solid state structures both compounds were found feature a distorted tetrahedral geometry that is largely consistent with reported structure diphenylphosphine-substituted variant, (Ph2PPrDI)Ni. To explore optimize synthetic utility this catalyst class, all three screened benzaldehyde hydrosilylation activity at 1.0 mol% loading over 3 h 25 °C. Notably, (Ph2PPrDI)Ni was be most efficient while phenyl silane effective reductant. A broad scope aldehydes ketones then hydrosilylated, silyl ether products hydrolyzed afford alcohols in good yield. When attempts made ester reduction, inefficient dihydrosilylation noted ethyl acetate no reaction observed several additional substrates. However, when an equimolar solution allyl added (Ph2PPrDI)Ni, complete C-O bond within 30 min °C generate propylene PhSi(OAc)3. expanded include six esters, under neat conditions, turnover frequencies up 990 h-1 achieved. This believed highest transition metal-catalyzed hydrosilylation. Proposed mechanisms (Ph2PPrDI)Ni-mediated carbonyl are also discussed.