RHCL(PPH(3))(3) CATALYZED HYDROSILYLATION OF STYRENE AND PHENYLACETYLENE WITH PHENYLSILANES

Reaction of styrene with Ph(2)SiH(2) catalyzed by RhCl(PPh(3))(3) (<0. 3 mol%) proceeds smoothly in THF to give Ph(2)SiH(CH(2)CH(2)Ph) in 77- 89% yields although the reaction is accompanied by formation of Ph(2)S iH(CH=CHPh), ethylbenzene, and Ph(3)SiH in small amounts. Similar reac tion in toluene also gives a mixture of Ph(2)SiH(CH(2)CH(2)Ph), Ph(2)S iH(CH=CHPh), ethylbenzene, and Ph(3)SiH with lower yield of the hydros ilylation product than the reaction in THF. Reaction of styrene with P h(2)SiD(2) catalyzed by RhCl(PPh(3))(3) in toluene gives a mixture of these products which are partly deuterated on the non-aromatic hydroge ns, The H-1 NMR spectrum of the products indicates complete deuterium scrambling on the hydrogen atoms of styrene and the phenylsilanes prio r to or during the reaction. Further reaction of Ph(2)SiH(CH(2)CH(2)Ph ) with HSPh catalyzed by RhCl(PPh(3))(3) gives Ph(2)Si(SPh) (CH(2)CH(2 )Ph). Hydrosilylation of styrene with PhSiH(3) catalyzed by RhCl(PPh(3 ))(3) is much slower than the reaction with Ph(2)SiH(2). Hydrosilylati on of phenylacetylene with PhSiH(3) catalyzed by 0.1 mol% of RhCl(PPh( 3))(3) gives PhSiH(2)(CH=CHPh) in 67% as the sole reaction product. Si milar reaction of 1-octyne gives PhSiH(2)[CH=CH(CH2)(5)Me]. These hydr osilylation products are converted into thiolato substituted organosil ane through RhCl(PPh(3))(3) catalyzed dehydrogenative condensation wit h HSAr (Ar = C6H5, C6H4-p-Me, C6H4-o-Me).