Alkenes (RCH= CHz, where R= CsH5, p-CH3CSH4, p-CHBOC6H4, p-C1CsH4, 2- naphthyl,(CH3) 3C, Me3SiO-(CH3), C, n-C4Hs0, and Et3Si) with HSiEt, with R u~(CO)~~ as a catalyst gave corresponding vinylsilanes (1, 6-13) without formation of simple addition products. Hydrosilanes such as HSiMe,, HSiEhMe, HSiPhMe,, and HSi (OEt), also yielded vinylsilanes. Alkenes having a hydrogen atom at the allylic position (1-hexene, ...