 Vinylsilane additions are less common, as a variety of methods to access allylic alcohols are available (including epoxidation of allylsilanes; see below).If the γ position of the allylsilane is substituted, two diastereomeric products may result.In the presence of Lewis acids such as titanium tetrachloride, ("E")-allylsilanes are highly selective for the "syn" diastereomer.