Fluorination polyfluoroalkene with

Polyhaloalkenes can be fluorinatcd with vanadium(V) fluoride. Terminal polyfluoroalkencs react at between — 20 and — 30 C, while internal polyfluoroalkenes are fluorinated at 40 to 150 C. Table 15 lists some examples. 

While methanol and ethanol react readily with a terminal polyfluoroalkene to give a high conversion to the fluorine-containing alcohol, e.g. formation of the extent of the conversion decreases very rapidly when propanol and butanol are employed. 

The various reactions of cyclic polyfluoroalkenes [85] (Figure 7.32) can largely be explained on a similar basis to that described above, although the opportunity for some rather more subtle orientation effects arises. Vinylic fluorine is generally replaced in preference to other vinylic halogens, either in the same molecule or in comparable systems, e.g. in the reaction of 7.32A with a deficiency of aUcoxide ion. In these cases, vinylic substitution is usually preferred over Sn2 processes. 

Nucleophilic perfluorophenylation reactions of terminal and internal polyfluoroalkenes have been studied.158 As expected, terminal alkenes first undergo substitution of one fluorine atom in the 1-position to form perfluorinated 1-arylalkenes. In turn, these primary products may further react with substitution of one vinyl or aromatic fluorine atom. Actually, these reactions proceed concurrently resulting in an isomeric mixture. For example, perfluoro(2-methyl-propene) is transformed into such a mixture (Table 3).158... 

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