Rearrangement of sulphenates

The spontaneous rearrangement of allyl p-toluenesulphenates to allyl sulphoxides was independently recorded by Mislow and coworkers and Braverman and Stabinsky. Mislow and colleagues201 have demonstrated that simple allyl alcohols such as 149, on conversion to the corresponding lithium alkoxides followed by treatment with arenesulphenyl chlorides, may be smoothly transformed at room temperature via the sulphenate esters into allylic sulphoxides 150 (equation 83). Braverman and Stabinsky202 have found that when the more reactive trichloromethanesulphenyl chloride is treated with allyl alcohol and pyridine in ether at — 70°, it affords trichloromethyl allyl sulphoxide and not allyl trichloromethanesulphenate as reported by Sosnovski203 (equation 84). 

Reaction of alkynols 156 with benzenesulphenyl chloride afforded either the vinylacety-lene sulphoxides 157 or the allene sulphoxides 158 depending upon the substitution pattern of alkynols 156. Vinylacetylene sulphoxides 157 result from a [2,3]-allylic rearrangement of the sulphenate ester 159 (equation 88). In the case of the cyclic... 

Allyl sulphenates, rearrangement of 720-736 Allylsulphenic acids 747 Allyl sulphinates, rearrangement of 670-676 Allylsulphinyipyrazolenines, photolysis of 749... 

Polychloromethylsulphonylbiphenyls, mass spectra of 154, 155 Polyenes, synthesis of 771 Polymerization, of sulphoxides 846 Polymer-supported reagents 928 Polymorphonuclear leukocytes 854 Poly(olefin sulphonejs, radiolysis of 916-922 Polysulphones, radiolysis of 913 Population analysis 14, 15, 21, 22 Propargylic sulphenates, rearrangement of 736-739... 

Rearrangement of acetylenic sulphenates to the allenic sulphoxides 151 was discovered when the synthesis of propargylic ester of trichloromethanesulphenic acid 152 was attempted (equation 86). This reaction is of general scope and gives very good yields of allenic sulphoxides (Table 14) from structurally diverse cohols and various sulphenyl chlorides Reaction of alkynols 153 with benzenesulphenyl chloride in the presence... 

Reaction of the carbanion of chloromethyl phenyl sulphoxide 409 with carbonyl compounds yields the corresponding 0-hydroxy adducts 410 in 68-79% yield. Each of these compounds appears to be a single isomer (equation 242). Treatment of adducts 410 with dilute potassium hydroxide in methanol at room temperature gives the epoxy sulphoxides 411 (equation 243). The ease of this intramolecular displacement of chloride ion contrasts with a great difficulty in displacing chloride ion from chloromethyl phenyl sulphoxide by external nucleophiles . When chloromethyl methyl sulphoxide 412 is reacted with unsymmetrical ketones in the presence of potassium tcrt-butoxide in tert-butanol oxiranes are directly formed as a mixture of diastereoisomers (equation 244). a-Sulphinyl epoxides 413 rearrange to a-sulphinyl aldehydes 414 or ketones, which can be transformed by elimination of sulphenic acid into a, 8-unsaturated aldehydes or ketones (equation 245). The lithium salts (410a) of a-chloro-/ -hydroxyalkyl... 

Where X is S or Se and Y is oxygen or a carbanionic site. The rearrangement of allyl sulphoxides to allyl sulphenates is an example. 

The addition of sulphene to 7V-benzylidene-2-hydroxyanilines, e.g. (211), gives an unstable adduct (212), which rearranges to give the 1,2,5-benzoxa-thiazepine (213). ... 

It has also been shown that reagents of type (45) in which the double bond is cis afford higher yields and greater stereoselectivity than the corresponding irons compounds [57], The cis (150) product prepared in this way could be isomerised to the required irons 15a product via a [2,3]sigmatropic rearrangement of a sulphenate ester to a 13-sulphoxide-14,15-m/ns-compound, and then treatment with trimethyl phosphite. 

Allylic sulphenic acids are transient intermediates in the rearrangement of episulphoxides carrying a suitably located H atom /ru/i5-but-2-ene episulphoxide gives diallyl thiolsulphinate via HaC=CH CHMeSOH, the product (145) existing in equilibrium with the butenyl thio-sulphoxylate (146). 

Brown s book on organic synthesis via boranes, ° and reviews on sulphene chemistry, the use of activated metals in organic and organometallic chemistry, the Wolff rearrangement of a-diazocarbonyl compounds, and ring contractions and expansions of vicinally disubstituted cyclobutanes and cyclopropylmethyl compoundsare also of appreciable relevance to bridged carbocyclic chemistry. Other pertinent, but more specialized, reviews are recorded in the various sections of this chapter. 

Sultenes, Sultines, and Sultones.—Further reports have appeared on the formation of sultones from SO3 and dienes and from the cycloaddition of c-amino-methylene-ketones and sulphene. Unusual sultone formations occurred during the reaction of a ketose derivative with mesyl chloride and during the rearrangements of bicyclic ketones that were induced by sulphuric acid, respectively. The kinetics of reactions of sultones (181) with nucleophiles and the enthalpy changes accompanying their alkaline hydrolysis," which allow an estimation of differences in ring strain between the five- and six-membered sultones, have been studied. 

A new method has been reported for the preparation of 1,2,3-benzoxathiazine-2,2-dioxides (314), Finally, 1,2,5-benzoxathiazepines (315) have been prepared through a novel rearrangement of the unstable adducts of sulphene with A -benzylidene-2-hydroxyanilides. The compound obtained was identical with that produced unambiguously by an alternative route. 

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