Perfluorocarboxylic acid derivatives

Enolphosphate phosphonates derived from perfluoroalkanoylphosphonates have a number of synthetic uses. Reactions of such compounds with nucleophiles such as amines or alcohols in the presence of catalytic amounts of tetrabutylammonium fluoride (tbaf) gave a,j5-unsaturated perfluorocarboxylic acid derivatives, presumably via a ketene type intermediate (equation 94) When a primary amine was employed as the nucleophile a,j -unsaturated amides were formed, which could be converted into fluorinated pyrimidi-nones by treatment with urea. On the other hand, butylcopper(I) reagent reduces such... 

Perfluorocarboxylic acid derivatives from perfluoroiodides via perfluoroalkyl halogenosulfonates... 

Scheme 11 indicates the usefulness of salts derived from Wittig ylide reagents and anhydrides of perfluorocarboxylic acids in the synthesis of fluorinated alkenylphosphonic diesters (127), often together with (epoxyalkyl)phosphonic diesters (128)(Rf = CF3 or... 

A simple method for the generation of metal derivatives of perfluoroalkyl carbanions by the decarboxylation of alkali salts of perfluorocarboxylic acids, has also been used. For example, heating potassium perfluoroalkyl carboxylates in the presence of dipyridine disulfides in DMF or sulfolane leads to the formation of the corresponding pyridine perfluoroalkyl sulfides [61] (Scheme 28). 

Radicals derived from decarboxylation of perfluorocarboxylic acids will undergo addition to ethyl vinyl ether to provide the expected homologs in 60% yields (eq 15). ... 

The preparation of per- and poly-fluorinated carboxylic acids and their derivatives om the corresponding iodides is covered elsewhere (see pp. 47—48), and patents dealing with the conversions of trichloroacetyl chloride into trifluoroacetic acid and trifluoroacetyl chloride and the manufacture of chlorine-free anhydrous trifluoroacetic acid by hydrolysis of trifluoroacetyl chloride have been published. Treatment of sodium or silver perfluorocarboxylates with phosphorus(ni) difluoride halides or phosphorus(v) oxy- and thio-difluoride halides gives the corresponding perfluoroacyl halides in good yield (see Scheme 2) in certain cases the intermediate... 

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