Lewis acid mediated intermolecular vinylsilylation of alkynes

Intermolecular vinylsilylation of the alkynes 1b-c, having an alkoxy group at the homopropargylic position, with the vinylsilane 2 proceeded in the presence of AlBr3 to give the corresponding dienylsilanes 3b-c in moderate to good yields. In contrast, no product was obtained in the reaction of 1-octyne. The AlBr3 mediated vinylsilylation of the phenylacetylene 9c, bearing methoxy group at the ortho position, also proceeded in good yield.