Tunable Stereoselective Hydrosilylation of PhC⋮CH Catalyzed by Cp*Rh Complexes

The catalysts [Cp*RhCl 2 ] 2 and [Cp*Rh(BINAP)](SbF 6 ) 2 (Cp* = pentamethylcyclopentadienyl; BINAP = 2,2‘-bis(diphenylphosphino)-1,1‘-binaphthyl) are effective for the hydrosilylation of phenylacetylene with triethylsilane, triethoxysilane, and triphenylsilane under mild conditions. [Cp*RhCl 2 ] 2 promotes the atypical anti addition to yield the β- Z isomer, whereas [Cp*Rh(BINAP)](SbF 6 ) 2 gives syn addition to form the β- E isomer. Extraordinarily high regioselectivity and stereoselectivity were observed for reactions involving triphenylsilane. Thus, tuning of the ligand set of Cp*Rh allows preparation of either the β- Z or β- E product.