Catalytic Hydrosilylation of Olefins and Ketones by Base Metal Complexes Bearing a 2,2′:6′,2″-Terpyridine Ancillary Ligand

Abstract The activities of [M(tpy)Br2] (M = Mn, Co, Ni, or Cu) for the hydrosilylation of olefins and ketones were investigated in the presence of NaBHEt3 as an activator. [Co(tpy)Br2] and [Ni(tpy)Br2] showed catalytic activities for the hydrosilylation of 1-octene with diphenylsilane. In particular, [Co(tpy)Br2] showed good catalytic activity. The linear anti-Markovnikov hydrosilylation product was predominant; however, a small quantity of the branched Markovnikov product was also produced. Generation of the branched product was suppressed by the addition of THF and pyridine as solvents. The reactivities of other olefins and silanes were also examined. In the hydrosilylation of ketones, unlike the hydrosilylation of 1-octene, all four complexes used in this study exhibited catalytic activity. Interestingly, in the reaction between diphenylsilane and acetophenone, the dominant product was the 1:2 double hydrosilylation product, not the 1:1 single hydrosilylation product, even in a reaction mixture of equal parts diphenylsilane and acetophenone.