Diphenyl Sulfurane

2-TRIFLUORO-l-PHENYL-l-(TEIFLUOROMETHYL) ETHOXY] DIPHENYL SULFURANE 

2-trifiuoro-l-phenyl-l- trijlucrromethyl[ethoxy] Diphenyl Sulfurane. Carbon tetrachloride is distilled directly from phosphorous pentoxide into a dry, 2-1., three-necked flask fitted with stoppers until 

700 ml. is oolleoted. The flask is quickly fitted with an adapter for use as a nitrogen inlet, a mechanical stirrer, and an adapter for solid addition (Note 5) to which is attached the 500-ml. flask containing the potassium alkoxide from Part A. A positive pressure of dry nitrogen is used to maintain inert atmosphere conditions. A white slurry is obtained when the powdered alkoxide is added to the stirring carbon tetrachloride at room temperature. Since all of the alkoxide does not transfer, the tared 500-ml. flask is reweighed, and the amount added to the reaction vessel is determined by difference (Note 6). The adaptor used for solid addition is quickly exchanged for a septum. 

The submitters report no problems in running the entire procedure on four times the scale described here. 

The use of potassium hydroxide rather than sodium hydroxide is dietated by solubility characteristics which make purification of the sodium alkoxide difficult. 

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Synthetic applications of organosulfur reagents are expanding rapidly. Stable sulfuranes are included for the first time in BIS[2,-2,2-TRIPLUORO-l-PHENYL-l-(TRIFLUOROMETHYL)ETHOXY] diphenyl SULFURANE and DIETHYLAMINOSULFUR TRI-FLUORIDE. The latter is used to transform an alcohol to a fluoride in p-NITROBENZYL FLUORIDE. The direct homologation of a ketone to a nitrile by use of p-TOLYLSULFONYLMETHYL ISOCYANIDE is illustrated in 2-ADAMANTANECARBONITRILE. Reagents with... 

BIS(SALICYCL1DENE)ETHYLENE-DIIM1NO COBALT(Il), 57, 78 BlS[2,2,2-TRIFLUORO-l-PHENYL-l-(TRIFLUOROMETHYL)ETIIOXY ] -DIPHENYL SULFURANE, 57, 22 l,2-BlS(TRIMETHYLSlLYLOXY)CYCLO BUTENE, 57, 1... 

The 2,2 -biphenylylene diphenyl sulfurane [10-S-4(C4)] has already been postulated by Trost et al. [38] and Hori et al. as an intermediate in the reaction of 2,2 -biphenylylene phenyl sulfonium salt with phenyl lithium. However, they could not directly prove the existence of the corresponding sulfurane as an intermediate. Sato and Furukawa tried to obtain the first crucial evidence for formation of 2,2 -biphenylylene diphenyl sulfurane 105 in the reactions of 2,2 -biphenylylene phenyl sulfonium salt 104 with PhLi in a THF solution by low temperature 1H, 13C and CH-COSY NMR experiments [95]. By elevating the temperature of a THF solution to room temperature, each solution became colorless, to give phenyl o-terphenyl sulfide 106 quantitatively, after work up, as shown in Scheme 41. 

Preparation. The sulfurane (I) is prepared most conveniently in nearly quantitative yield by treatment of an ethereal solution of the [>ota sium salt of hexafluoro-2-phenyl-2-propanol (RfOH, prepared by the reaction of the alcohol with potassium metal) and diphenyl sulfide with chlorine at - 78°. Removal of the potassium chloride by filtration and of the ether by evaporation under vacuum leaves the white, crystalline sulfurane (I), which can be crystallized from pentane. Moisture must be avoided... 

Several j3-sultones are claimed to be formed by treatment of alkenes with sulfuric acid or by heating alkenesulfonic acids. Treatment of 2,2-dimethyl-1,1-diphenyl-1-propanol with concentrated sulfuric acid at room temperature is said to give 3-(l,l-diphenylethyl)-3-methyl-l,2-oxathietane 2,2-dioxide (96% yield). Treatment of sodium 3-bromo-2-hydroxybutanesulfonate with phosphorus trichloride is reported to give a low yield of 4-(l-bromoethyl)-l,2-oxathietane 2,2-dioxide.1,2-Oxathietane 2,2-dioxide is suggested as an intermediate in the reaction of /3-hydroxyethanesulfonyl chloride with trimethylamine to give the zwitterion 502. The first four-membered monocycUc sulfurane oxides 502a have been reported. 

Furukawa et al. have reported one of the most convenient methods to prepare various Martin s type sulfuranes as shown in Scheme 25 [61]. Thianthrene S-monoxide (33) was found to react with alkyl Grignard reagents affording the o,o -bis-Grignard reagent of diphenyl sulfide, which was converted initially into the corresponding diols 34 on treatment with aldehydes or ketones, and then to the Martin s sulfuranes 35 by treatment with tert-butyl hypochlorite. 

Tetraphenylsulfurane is the simplest but most unstable among the tetraaryl-sulfurane species. Although only tetraphenyltellurane has been isolated, and its crystal structure has been determined, tetraphenylsulfurane and -selenurane have neither been detected directly nor isolated in the earlier studies. Furukawa and Sato reinvestigated the reactions of triphenyl sulfonium salt 99 and diphenyl sulfoxide 100 with phenyllithium (PhLi) in tetrahydrofuran (THF) in order to attempt detection of tetraphenylsulfurane [10—S—4(C4)] 101 directly by 13C, and CH-COSY NMR experiments at low temperature, as shown in Scheme 40 [91]. As results, the detection of tetraphenyl sulfurane has been achieved by low temperature NMR studies while tetraphenyl tellurane has been isolated [92]. 

These NMR experiments at low temperature and the product analysis indicate that both triphenylsulfonium salt and diphenyl sulfoxide react with PhLi to give an identical tetraphenyl sulfurane 101 as a discrete intermediate at low temperature, which, on warming to room temperature, decomposes to diphenyl sulfide 102 and biphenyl 103. Interestingly, the four phenyl groups in the sulfurane 101 become spectroscopically identical, suggesting that the pseudorotation takes place rapidly even at low temperature such as -105 °C. 

Martin s sulfurane (1) enables quick and efficient elimination of secondary and tertiary alcohols 2 to yield alkenes 3 along with production of diphenyl sulfoxide (4) and alcohol 5.1,2 This highly reactive dehydrating reagent is effective at room temperature and below, and reactions are often complete in less than one hour. Primary alcohols rarely react to yield alkenes and instead are transformed into ethers. The title reagent is available from numerous commercial sources and can be prepared in large quantities according to several published procedures.3... 

Analogous chemistry was observed by Denney and co-workers11 when divalent sulfur nucleophiles were allowed to react with dioxetanes. Thus, diphenyl sulfide gave epoxide and diphenyl sulfoxide, presumably via the sulfurane (63), as shown in Eq. (50). When the ligands on the sulfur nucleophile were alkoxy groups, NMR evidence for the intermediary sulfuranes was provided. Similar results were observed by Wasserman... 

Diphenyl-2,2 -dicarboxylic acid, 35 Diphenyldi( 1,1,1,3,3,3-hexafluoro-2-phenyl-2-propoxy)sulfurane, 239 Diphenyl diselenide, 235 Diphenyl disulfide, 31, 235-236, 313... 

Wittig reported the isolation of biphenyl and diphenyl-sulfide upon treatment of triphenylsulfonium salt with phenyUithium. ) Although the origin of these products may be via the decomposition of a sulfurane, a... 

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