Fluorosulfites

The reaction of 1,2-diols with sulfur tetrafluoride leads to fluorosulfites, which on hydrolysis, give monofluoro alcohols [555] (equation 74)... 

Methyl fluorosulfite, 16 306 Methylformamide, metal carbonyl derivatives, 8 27... 

The formation of intermediate fluorosulfites also appears to be characteristic of the reactions of 1,3- and 1.4-diols however, these compounds were not isolated. The reaction of propane-1,3-diol, butane-1,3-diol and butane-1,4-diol with sulfur tetrafluoride gives, respectively, 3-fluoro-propan-l-ol, 3-fluorobutan-l-ol and 4-fluorobutan-l-ol.59... 

Aliphatic a-hydroxy ketones react with sulfur tetrafluoride, generally to provide trifluoroal-kanes. However, under carefully chosen conditions the carbonyl group in hydroxy ketones remains intact while the hydroxy group undergoes selective substitution by fluorine. Thus, 5-hydroxyoctan-4-one reacts with sulfur tetrafluoride (20°C, 3 h) to give a 1 1 mixture of 5-fluorooctan-4-one(l b) and 2-oxo-l-propylpentyl fluorosulfite.63 a-Fluoro ketones 1 are formed in high yield and as the sole product when diethyl ether is used as solvent.64... 

Reaction of esters of hydroxyalkanoic acids with sulfur tetrafluoride, unless forcing conditions arc applied, generally results in selective replacement of the hydroxy group by fluorine to give almost equimolar mixtures of fluoroalkanoates 3 and alkoxycarbonylalkyl fluorosulfites 4 in high total yield.65... 

The type of products formed in reactions of /(-hydroxy acids with sulfur tetrafluoride depends on the substituents on the carbon alom adjacent to the hydroxy group. Acids such as 3-hy-droxypropanoic acid (21) and 3-hydroxybutanoic acid (22) give, in addition to 1,1,1,3-tetra-fluoroalkanes, mainly dimeric products, i.e. fluorinated esters or ethers, together with small amounts of unsaturated acid fluorides. In contrast, n7C -4,4,4-trifluoro-3-hydroxybutanoic acid (23), depending on the reaction conditions, affords 3,3,3-trifluoro-l-(lrifluoromethyl)propyl fluorosulfite or a mixture of 1,1,1.2,4,4,4-hcptafluorobutanc and l,l,1.4.4,4-hcxafluorobut-2-ene.116... 

Hydroxy-1,2-dicarboxylic acids, such as n- and L-a-hydroxysuccinic acid53 and D-tartaric acid.120 on treatment with sulfur tetrafluoride give complex mixtures of fluoroalkanes, fluoro-alkenes, fluoroalkyl fluorosulfites and cyclic five-membered ethers, derivatives of 2.2,5.5-tet-rafluorotetrahydrofuran. In the case of D-tartaric acid the cyclic ethers are predominant components (64%) of the reaction mixture.120 Linear and cyclic mono- and disulfites formed in these reactions give, after hydrolysis, the corresponding linear and cyclic polyfluoro alcohols and diols in high yield.53120... 

Dimethyl sulfoxide reacts exothermically with tungsten(VI) fluoride to give a viscous oil which could be a complex, and from which a low yield of bis(fluoromethyl) ether can be obtained 44 sulfur tctrafluoride gives the same product, but in good yield. Also like sulfur tetrafluoride, tungsten(VI) fluoride will cleave45 sulfites [(RO)2SO] into fluorosulfites (ROSOF) at 0 C. 

Thionyl fluoride can be prepared by the reaction of thio-nyl chloride with metal fluorides such as zinc(II) fluoride1 and arsenic (III) fluoride,2 and with metal fluorosulfites.3 It is also obtained by the action of hydrogen fluoride upon a mixture of tetrasulfur tetranitride and copper(II) oxide4 and by the reaction of hydrogen fluoride with thionyl chloride in the absence of6 or in the presence of6 antimony(V) fluoride as catalyst. Another method and the simplest on a laboratory scale involves the reaction of antimony(III) fluoride with thionyl chloride in the presence of antimony ) chloride as catalyst.7 This last procedure is described below. 

Further examples of reactions of aliphatic and alicyclic polycarboxylic acids with sulfur ictra-fluoride or sulfur tetrafluoride/hydrogen fluoride are known.The reaction of aliphatic hydroxycarboxylic acids with sulfur tetrafluoride can give different products depending on the reaction conditions, the position of the hydroxy group, and the presence of other substituents. The main products from a-hydroxycarboxylic acids are trifluoroalkyl fluorosulfites, e.g. 19, which can be hydrolyzed quantitatively to the corresponding alcohols. ... 

An electron-withdrawing trifluoromethyl substituent at the /8-carbon atom prevents the substitution of the hydroxy group by fluorine. Fluorosulfites, e. g. 22, and, by subsequent hydrolysis, the corresponding secondary alcohols can be obtained." ... 

The stereochemical outcome of the overall reaction is interpreted as the consequence of a stepwise fluorination.4-5 The first fluorine comes in via an SN2-type substitution of the cyclic intermediate 4 with inversion. The second fluorine is introduced with retention from the intermediate 7, which is formed by the action of hydrogen fluoride and sulfur tetrafiuoride on intermediate fluorosulfite 5 via 6. 

Mild treatment of dimethyl (+ )-r.-tartratc with sulfur tetrafiuoride alone gives the isolable intermediate 2-fluoro-l, 2-bis(methoxycarbonyl)ethyl fluorosulfite (5) in 98% yield.4 This can be hydrolyzed to dimethyl (- )-(2.S,3.S)-2-fluoro-3-hydroxysuccinate (6) in 97% yield. Hence, by proper choice of the reaction conditions, one or two hydroxy groups can be selectively substituted by fluorine in dialkyl tartrates.4... 

See Niobium(V) chloride and hexachloroniobates(V), synthesis 23 Potassium fluorosulfite, synthesis 28... 

Previous methods for the preparation of sulfuryl fluoride have involved either the reaction of elemental fluorine with a variety of sulfur-oxygen compounds or the reaction of silver fluoride with sulfur dioxide. A very simple procedure for the preparation of sulfuryl fluoride in good yield involves the reaction of potassium fluorosulfite with chlorine gas. ... 

The reaction of chlorine with an appropriate amount of potassium fluorosulfite (synthesis 28) is carried out in a... 

If the upper half of the reaction tube is heated to 170 to 180° by means of an electric tube furnace, the sulfuryl chloride fluoride (formed in the lower half of the tube) reacts with potassium fluorosulfite in the heated portion of the tube to produce sulfuryl fluoride. The reaction is substantially complete when the narrow warm zone characteristic of the formation of sulfuryl chloride fluoride has reached the externally heated portion of the tube, where the SO2CIF SO2F2 transformation takes place. A mixture of the two liquid products is formed in the flask surrounded with Dry Ice the two products can be separated easily by fractional distillation and may be identified by their infrared or mass spectra. ... 

Potassium fluorosulfite can be prepared by the reaction of potassium fluoride with sulfur dioxide in an autoclave or by grinding potassium fluoride in a ball mill under an atmosphere of sulfur dioxide. The reaction can be carried out by treating potassium fluoride with a solution of sulfur dioxide in dimethyl sulfoxide or in tetramethylene sulfone (tetrahydrothiophene 1,1-dioxide, Sulfolane) without resorting to costly apparatus and with practically quantitative yields. The starting materials must, in every case, be completely anhydrous. 

After centrifugation, about 75% of the original solvent (dimethyl sulfoxide) and a significant amount of dissolved excess sulfur dioxide can be recovered. This dilute solution can be enriched with more sulfur dioxide and used again. If the ether solutions of dimethyl sulfoxide are not worked up, there is a loss of 1 mol of dimethyl sulfoxide per mol of potassium fluorosulfite. 

Potassium fluorosulfite is a colorless crystalline powder which, because of hydrolysis, smells of sulfur dioxide and which must necessarily be stored under protection from moisture. The following relationship applies for the sulfur dioxide vapor pressure over potassium fluorosulfite ... 

Chemically, potassium fluorosulfite behaves as though it were activated potassium fluoride. At only slightly elevated temperatures, potassium fluorosulfite converts carboxylic chlorides and the chlorides of boron, phosphorus, and sulfur to the corresponding fluorides. ... 

The phosphonitrilic fluorides do not result from the interaction of ammonium fluoride with phosphorus pentachloride ammonium hexa-fluorophosphate is formed instead (47). They may be prepared indi-j ectly by the reaction of potassium fluorosulfite with the chlorides at 100°-120° (75),... 

Clinical studies show the following ions competitively inhibit the mammalian thyroid I- transport CIO4 (perchlorate) > ReOJ (perrhenate) > BF4 (fluoroborate) > SeCN- (selenocyanate) > SO3F- (fluorosulfite) > SCN- (thiocyanate) > I > NO (nitrate) > OCN (cyanate) > Br (bromide)2. They are all monovalent anions with a partial molal ionic volume of 25-50 ml/mole. Most of them are spherical or... 

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