Sulphenates Trichloromethanesulphenates

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). 

Braverman and Grendi206 have shown that, depending on the type of substitution, allylic trichloromethanesulphenates undergo rearrangement to allylic trichloromethyl sulphoxides by one of two different pathways (equation 85). Rearrangement according to route a has been observed with allyl, crotyl and a, a-dimethylallyl sulphenates. It occurs... 

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... 

Dichlorosulphine is formed in good yield by the thermal decomposition of p-anisyl trichloromethanesulphenate in acetonitrile or chloroform. The reaction is very sensitive to solvent polarity, and, in non-polar solvents, rearrangement of the sulphenate to the sulphoxide occurs by a polar mechanism. Since the trichloromethanesulphenate anion is known to give dichlorosulphine, an intermediate ion-pair is postulated, i.e. 

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