Sulfenic acid esters ethers

Disaccharides. A mixture of startg. thioglycoside, sulfenic acid ester, and 4A molecular sieves in acetonitrile treated with trimethylsilyl triflate at — 35° under N2, stirred at the same temp, for 40 min, and worked up with NEt3 product. Y 90% (a/ 3 5 95). The stereoselectivity was solvent-dependent, being a-selective in ether and P-selective in acetonitrile. F.e. and substituent effects s. Y. Ito, T. Ogawa, Tetrahedron Letters 28, 4701 (1987). 

The addition of an allyl alcohol to racemic allenyl sulfoxides results in vinyl ethers with the sulfinyl moiety at C-1 that undergo sigmatropic rearrangements upon distillation to produce 2,4-dienones after ehmination of sulfenic acid. In one example, an isomeric vinyl ether was obtained with a sulfinyl methyl substituent at C-2 that gave rise to a sulfinyl enone upon rearrangement [138]. In related work, the addition-elimination of an allyl alkoxide to a functionalized vinyl sulfoxide results in a sulfinyl enol ether that rearranges with loss of sulfenic acid to the unsaturated ester [139-141] (Scheme 21). 

A mercury-free route to allyl vinyl ethers that relies on the Michael addition of allyl alcohols to unsubstituted alkenyl sulfoxides, followed by thermal loss of sulfenic acid and concurrent Claisen rearrangement has been described [145]. This methodology has been applied to the synthesis of isocar-bacyclin [146]. Posner reported an acid-catalyzed protocol that produces conjugated dienoate esters from allylic alcohols and a sulfinyl orthoester [147]. Additionally, the use of propargyl alcoholates and a chloro alkenyl sulfox-... 

The trapping of the penicillin sulfenic acid with dihydropyran has been previously discussed (Cooper and Spry, 1972). Further examples of trapping with vinyl ethers have also been disclosed (Ager et al., 1972 1973). The sulfoxide (106) reacted with isobutyl vinyl ether resulting predominantly in unstable vinyl ether (139). On treatment with a catalytic amount of p-toluenesulfonic acid in benzene, 139 afforded the dihydrothiazine (140). The reaction of 139 with methanolic hydrogen chloride resulted in a smooth transformation to the acetal (141). When 1,1-diethoxyethy-lene was used, the corresponding vinyl ether was not observed. Instead, the preferred course of the reaction was an in situ hydrolysis to the ester (142). 

Types of compounds are arranged according to the following system hydrocarbons and basic heterocycles hydroxy compounds and their ethers mercapto compounds, sulfides, disulfides, sulfoxides and sulfones, sulfenic, sulfinic and sulfonic acids and their derivatives amines, hydroxylamines, hydrazines, hydrazo and azo compounds carbonyl compounds and their functional derivatives carboxylic acids and their functional derivatives and organometallics. In each chapter, halogen, nitroso, nitro, diazo and azido compounds follow the parent compounds as their substitution derivatives. More detail is indicated in the table of contents. In polyfunctional derivatives reduction of a particular function is mentioned in the place of the highest functionality. Reduction of acrylic acid, for example, is described in the chapter on acids rather than functionalized ethylene, and reduction of ethyl acetoacetate is discussed in the chapter on esters rather than in the chapter on ketones. 

Buffer catalysis of the hydrolysis of phenyl (311 R = Ph) and methyl (311 R = Me) benzenesulfinates to give the sulfinic acid (312) and alcohol ROH is strongly accelerated by both carboxylate and amine components of the buffer which give Bronsted /i values of approximately unity on separate lines. The carboxylates are about 44 tunes more effective than amines of similar basicity. A concerted. S n2 mechanism with a hypervalent intermediate (313) is proposed for the nucleophilic reaction of these esters.286 The reaction of the thiosulfinate esters (314) with sulfenyl chlorides RSCI and sulfenate esters (315) to give sulfinyl chlorides and disulfides and sulfinate esters and disulfides, respectively, has been studied.287 Hydrolysis of 2-(3-aminophenyl)sulfonyl-ethanol hydrogensulfate gives under different conditions various products such as the ether (316) and the sulfone (317).288... 

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