Fluorinated sultone

The alkoxide formed by attack of the carbonyl group of perfluorobutyrolactone opens the oxirane ring of hexafluoropropene oxide at the central carbon atom [37] (equation 33). A fluorinated sultone reacts with halogenoalkanes in the presence of metal fluoride [3S] (equation 34). 

Technological applications have been found for the oxathietane 1,1-dioxides. Ethane ) -sultones (19) substituted with long, saturated hydrocarbon chains have been developed as foam-producing surfactants and detergents. Attention is being given to the fluorinated sultones (20), especially by Soviet... 

The new sulfonic acid support/activator was synthesized by the ring-opening reaction of a fluorinated sultone with an SBA-15 silica surface (Fig. 20.4). 

A wide range of amines and their derivatives have been shown to react with both saturated and unsaturated aliphatic sultones to produce the corresponding aminosulph-onic acids (equation 109)166. Amines and their derivatives react rapidly with fluorinated / -sultones to form rearrangement products (equation 110)86. 

Perfluorinated acid fluorides containing heteratoms are also accessible by ECF. Long-chain perfluorinated acid fluorides produced by ECF containing nitrogen (10—12), oxygen (13), and sulfur (14,15) have been reported. The fluorinated mixed sulfonic acid—carboxyflc acid precursors are also known. ECF of hydrocarbon sultones has led to formation of FS02(CF2) C0F, where n = 2,3 (16). 

Carbonyl sulfonyl fluorides of the formula FC0(CF2) S02F have been prepared by electrochemical fluorination of hydrocarbon sultones (41,42). More commonly in a technology pioneered by Du Pont, perfluoroalkanecarbonyl sulfonyl fluorides are prepared by addition of SO to tetrafluoroethylene followed by isomerization with a tertiary amine such as triethylamine (43). 

Using a general procedure for the careful fluorination of sulfur-containing compounds, 1,2-oxathiane 2,2-dioxide 16 can be successfully fluorinated by treating the sultone with a mixture of elemental fluorine and helium gas at —78 °C for 8h, after which the crude reaction product is collected and fractionated in cooled traps <1991IC789>. The perfluoro sultone, that resulted, was isolated and characterized by and NMR spectroscopy, and MS. 

The thermolysis of fluorinated /3-sultones, the most stable derivatives of oxathietane dioxides, generally gives isomerization rather than elimination (Scheme 18) (72AG(E)583). 

The reaction with ethylene is visualized as an alkene exchange to give the unstable parent /3-sultone, which undergoes ring opening and concomitant proton shift to give ethylenesul-fonic acid. The latter reacts with the fluorinated /3-sultone with ultimate formation of ethylenebis-sulfonic acid (Scheme 53) (70BAU574). 

Another approach to /3 -sultones involves the in situ generation of sulfene, or its zwit-terionic equivalent, and its subsequent addition to perhalogenated ketones or aldehydes in yields of 60-80% (Scheme 101) (67DOK(172)1327, 69CI(L)457, 76CJC2652). The chemistry of fluorinated (3 -sultones has been reviewed (72AG(E)583>. 

In contrast to other known fluorinated /3-sultones, reaction of compound 48 with triethylamine does not give the expected isomer 49, but only its decomposition products pentafluoropropionyl fluoride 50 and fhiorosulfonyldifluoro-acetyl fluoride 51 (Scheme 10) <2003JFC(121)147>. 

The only methodology pertinent to the formation of 1,2- and 1,3-oxathietanes and their oxidized forms involving S-C and O-C bond formations is that for the preparation of /3-sultones. It is now well established that [7t2s+Jt2s] cycloaddition of sulfur trioxide with an alkene generates /3-sultones in moderate to excellent yields (Equation 1). Indeed, the previous version of this chapter detailed numerous examples of the formation of /3-sultones (especially fluorinated compounds) by the reaction of SO3 with an appropriate alkene at elevated temperatures <1996CHEC-II(1B)1083>. 

While the previous version of this chapter contained small sections on the synthesis of fluorinated and nonfluorinated /3-sultones along with /3-sultines and 1,2-oxathietanes, there has been no major new advances on the synthesis of these types of systems over the last decade. It appears that until practical industrial or medicinal uses are found, new methodologies for the constmction of such systems will not be developed. 

The most important use of /3-sultones is for the preparation of fluorinated polymers such as Nafion 64. These solid acid catalysts containing perfluorinated sulfonic acid groups have been known for many years and the presence of the electron-withdrawing F atoms increases the acid strength of the terminal sulfonic acid groups, which become comparable to that of pure sulfuric acid. Prior to the last decade, Nafion had been in use as a superacid, a fuel cell electrolyte and as a membrane-ion separator <1996CHEC-II(1B)1083>. 

Dioxathiolane 2,2-dioxides (cyclic sulfate esters of 1,2-diols) are used in practice like sultones to introduce acid substituents into nitrogen heterocycles (48BSF1002), especially into cyanine dyes (58GEP1028718). Fluorinated derivatives are useful in the treatment of textiles such as cotton to impart wash and wear characteristics (62USP3055913). The conversion of cyclic sulfates into resinous film-forming polymers has been likewise patented (64USP3154526). 

The S-0 stretching frequency in the IR spectra of 1,2-oxathietane 2-oxides is observed at 1150-1190cm . The carbonyl stretching frequency in 1,2-oxathietane-4-one 2-oxide is observed at 1840 and 1856 cm". The sulfonate IR absorptions in 1,2-oxathietane 2,2-dioxides are 1370-1408 and 1176-1235 cm", except for the fluorinated derivatives, the absorption of the tetrafluoro- 3-sultone being reported at 1470cm". Fluorine-19 (nmr) chemical shifts and coupling constants are useful in structural and conformational studies of... 

Oxathietane 2,2-dioxides (e.g., 448) are isolated in good yields from the reaction of sulfur trioxide with fluorinated alkenes, fluorinated dienes, ° and from the reaction of the sulfur trioxide donor 499 with fluorinated alkenes. Zwitterionic intermediates ( C-C-S020 ) are suggested. An explosion has been reported in the addition of sulfur trioxide to tetrafluoro-ethylene. Tetrafluoroethane /3-sultone (498) also is obtained by treatment of fluorosulfonyldifluoroacetic anhydride with antimony trichloride. ... 

The reaction is believed to be a chain process initiated by attack of a nucleophile (e.g., fluoride ion) on the sulfur atom. The fluorosulfonylacetyl fluorides are likely intermediates in the reaction of fluorinated 3-sultones with nucleophiles (water,hydroxide ion,900,908.928 893,898b,sosd,... 

Fluorinated alkenes320-323 and many simple alkenes324-327 give / -sultones (equation 70) in reasonable yields, although these sultones are sometimes too unstable to isolate. In the latter case, a carbyl sulphate may be produced328, as exemplified in equation 71. 

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