A stereoselective synthesis of silylated polyunsaturated halides from α,β-epoxysilanes

A new synthetic approach to silylated polyunsaturated halides has been developed, starting from the readily available (1E,3E)-1,4-bis(trimethylsilyl)-1,3-butadiene and (3E)-1,4-bis(trimethylsilyl)-3-buten-1-yne. A simple epoxidation reaction, followed by regioselective α-opening of the epoxide ring by metal halides affords the corresponding halohydrins with a high degree of stereoselectivity. A subsequent β-elimination reaction from these compounds leads to (Z,E)-dienyl halides and to (Z)-enyne halides.