Perfluoro-3,3-dimethyl-2(E)-pentene by fluoride ion catalyzed addition of octafluoroisobutene to hexafluoropropene

The fluoride ion catalyzed [1] oligomerization of perfluoroolefins has been employed extensively to prepare higher homologs [2,3,5-10]. When unlike partners react, the reaction might take either of two courses, depending on which olefin accepts fluoride ion to become the nucleophile. In all reported cases where the structure of the product allows the mechanism to be inferred, the less substituted (by carbon) olefin becomes the nucleophile, albeit at the more substituted center.