1,5-hydride shift in the aluminum chloride promoted allylsilylation of 5-silyl-1-alkenes

Abstract

Linear 4-alkyl-5-silyl-1-alkenes 1a-c react with allylsilanes 2a,b in the presence of aluminum chloride catalyst at 40 degrees C to give unusual allylsilylation products 3a-d derived from an intramolecular silyl group rearrangement in 23-57% yield. The reaction of cyclic 1-allyl-2-(trimethylsilyl)cycloalkanes 1d,e with 2 gave the silyl-rearranged isomers of 1 in addition to the allylsilylation products 3e,f. The results are consistent with silylenium ion formation and a 1,5-hydride shift in the allylsilylation and isomerization.