The titanium tetrachloride-mediated addition of allyltrimethylsilane or 1, 8-bis (trimethylsilyl)- 2, 6-octadiene and trifluoroacetic anhydride led to trifluoromethyl-diallylcarbinol or (dl)-1- trifluoromethyl-2, 5-divinylcyclopentanol, respectively, in fair yields; this latter was further converted into several 1-trifluoromethyl-2-vinylcyclopentane derivatives.