Sulphur tetrafluoride

The tetrafluorides of the elements can be prepared. They are all less stable than the corresponding hexafluorides and are hydrolysed readily by water. They can all be used as fluorinating agents and sulphur tetrafluoride is extensively used for this purpose, for example the fluorination of organic carbonyl groups ... 

The structure of sulphur tetrafluoride, and probably also SeF and TeF4, is trigonal bipyramidal with one position occupied by a lone pair of electrons ... 

Sulphur dioxide Sulphur hexafluoride Sulphuric acid Sulphur monochloride Sulphur pentafluoride Sulphur tetrafluoride Sulphuryl fluoride Sulprofos... 

Sulphur tetrafluoride C T Stainless steel or Hastelloy Class for moist gas... 

The reactions of triphenylphosphazenyl derivatives with many other electrophilic species have been described. With sulphur tetrafluoride, sulphur imines are formed, possibly via the four-centred intermediate (24) ... 

Air Products, USA., has developed bis-(2-methoxy ethyl) aminosulphur trifluoride as a cost effective, safe, stable fluorinating agent, made by reaction of di-2-methylethylamine with sulphur tetrafluoride and trade named Deoxo-Fluor, which replaces the more temperamental diethylaminesulphur trifluoride. Thus, p-phenylethyl alcohol was converted to P-phenylethyl fluoride in 85% yield (Stinson, 1999). 

Sulphur tetrafluoride C T Stainless steel or Hastelloy C lined containers. Glass suitable for short exposures if dry. Tygon for low-pressure connections Glass for moist gas... 

The conventional conversion of carbonyl systems by sulphur tetrafluoride into difluoroalkyl compounds has been modified in the reaction of dithioacetals with tetra-n-butylammonium dihydrogentrifluoride and A -bromo- or AModosuccinimide. Yields of the difluoroalkanes are generally in excess of 70% [35]. 

Sulphur Tetrafluoride, SF4, has been prepared3 by heating at 120° C. a mixture of cobalt trifluoride, fluorspar and sulphur. It is a colourless gas, which may be condensed to a liquid in a vessel surrounded by liquid air. 

DAST was first used as an alternative fluorinating agent to sulphur tetrafluoride, by Middleton [159]. Although DAST, prepared by the reaction of SF4 with diethylamino-trimethylsilane [160] (Figure 3.26), can be used in normal laboratory glassware at... 

Generally, sulphur tetrafluoride can only be used for fluorodehydroxylations of acidic alcohols, otherwise extensive decomposition to side-products predominates. However, (3-fluoroamino acids can be prepared by such a process [7]. 

Sulphur tetrafluoride, a colourless gas (b.p. 38° C) with toxicity of the same order as... 

Essentially the same route as that of Ruff has been followed by us, except that two new reducing agents whose chemistry is under study in these laboratories, namely sulphur and selenium tetrafluorides, have been used. Attention has already been drawn to the usefulness of selenium tetrafiuoride as a mild reducing agent in fluorine chemistry while sulphur tetrafiuoride also gives evidence of possessing similar properties. In the first series of experiments, palladium trifluoride, formed by the reaction between palladous iodide and elementary fluorine at room temperature, was treated with a stream of sulphur tetrafluoride at 250-300°. The violet-coloured powder which resulted was proved, by Af-ray examination, to contain palladium difluoride in admixture with about 10% of palladium metal. 

Chemical properties. Water hydrolysed the solid platinum tetrafluoride slowly, some platinum being precipitated as dioxide and some remaining in solution as hexafluoroplatinate(iv) ion. Material from which all the bromine trifluoride had not been removed reacted much more vigorously. Hydrogen reduced the fluoride to platinum at 100° below that temperature there was no reaction. Sulphur tetrafluoride was passed over platinum tetrafluoride heated to 300° in a closed glass apparatus. Chemical and X-ray analysis showed that the compound remained unchanged. 

Special reagents. With the exception of sulphur tetrafluoride, obtained from E. I. duPont de Nemours and Co., Wilmington, Delaware, and anhydrous hydrogen fluoride, from Mattheson Co., Inc., Newark, the chemicals and reagents used have been the same as in Part II. 

Sulphur tetrafluoride converts keto-steroids such as (70) into their difluoro-analogues, e.g. Reaction of anhydrous neutral alumina with the di-... 

Adamantyltetrafluorophosphorane (23) cannot be prepared from the phos-phonyl difluoride (77) by treatment with sulphur tetrafluoride. Instead, it has been prepared in good yield by Lewis-acid-induced cleavage of 1-fluoroadamantane the first time this has been achieved with an alkyl fluoride. ... 

The tetrafluorophosphorane (60) has been prepared by an unusual fluorination reaction, using sulphur tetrafluoride. In (60), the axial fluorines are non-equivalent, as shown by F n.m.r. spectroscopy at low temperatures. Above 0 °C the phosphor-ane decomposes, forming the expected phosphetidine (88). ... 

The reactions of phosphazenes (prepared in situ from aminophosphonium salts and triethylamine) with sulphur tetrafluoride have been further explored. An example is shown in reaction (3), where X is a bridging alkyl or aryl group. However, when X... 

A mixture of 2-t-butylfuran and 2,5-di-t-butylfuran is obtained by the action of t-butyl chloride on furan in the presence of mesitylene nolybdenum tricarbonyl." The intermediate in the nitration of furan-2-aldehyde in acetic anhydride has been identified as compound (26). Treatment of 5-bromo-2-furoic acid with sulphur tetrafluoride in hydrogen fluoride yields the dihydrofuran (27). Bromo-furans are converted into aryl-furans by crosscoupling with aryl Grignard reagents in the presence of nickel(II)-phosphine complexes. 2-Furoic acid is lithiated at position 5, 3-furoic acid at C-2. 2-Methylfuran yields the 5-methylthio-derivative by lithiation and subsequent treatment with dimethyl disulphide. The corresponding phenylthio-compound (28) has been converted into a series of 4-substituted 2-methyl-furans (29 R = alkyl, MeaSi, CO2H, or RCHOH) by the sequence bromi-nation, lithiation, treatment with the appropriate electrophile, and, finally, desulphurization with Raney nickel. 2-Lithiofuran reacts with copper(II)... 

Fluoiination of dichloromaleic anhydride with sulphur tetrafluoride at 300 C in the presence of boron trifluoride as catalyst was used to prepare the perfluoro-... 

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