Allylation reagents, which possess geminal bis-trimethylsilyl substitution, are readily prepared from E- or Z-alkenyl bromides. The reactivity of 3,3-bis(trimethylsilyl)-2-methyl-1-propene (1) is described and predominantly provides ene reactions with aldehydes to give alcohol 2 in the presence of BF3.OEt2. Alternatively, Sakurai allylation reactions of 1 are observed by using stronger Lewis acids in methylene chloride to exclusively yield E-trisubstituted alkenylsilanes 3.