Platinum-Catalyzed Alkenylation of Acetals with Alkenylsilanes

In the presence of catalytic amounts of PtCl₂ and LiI, alkenylsilanes reacted with dimethyl acetals of aromatic aldehydes in acetonitrile to give allylic methyl ethers. This alkenylation reaction occurred not at the α-carbon bound to silicon but at the β-carbon of alkenylsilanes. Use of chlorotrimethylsilane as an additive was effective in promoting the alkenylation of certain acetals. The PtCl₂-catalyzed hydrosilylation of terminal alkynes with triethylsilane and subsequent alkenylation of acetals enabled easy and rapid synthesis of allylic ethers.