Sulfenic acid esters alcohols

Sulfenic acid esters from alcohols and reverse reaction Protection of nucleoside hydroxyl... 

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-... 

In contrast to the free acids, sulfenate esters, amides and halides are more stable. Disulfides (52) can be obtained from thiols by mild oxidation (see p. 57), and sulfenyl chlorides () can in turn be prepared from disulfides (52) by treatment with chlorine (Scheme 30). Sulfenyl chlorides (51) react with alcohols to give esters, e.g. the methyl sulfenate (53) which on alkaline hydrolysis yields the sulfenic acid (45) (Scheme 30). 

The 2-sulfonyloxaziridine (57) is a more selective oxidant than peracids. The reagent has been employed in the oxidation of sulfides to sulfoxides, disulfides to thiolsulfinates, selenides to selenoxides, thiols to sulfenic acids, organometallic reagents to alcohols and phenols, ketone and ester enolates to a-hydroxycarbonyl compounds (equation 31)41. The oxidation of chiral amide enolates gives optically active a-hydroxy carboxylic acids with 93-99% enantiomeric excess42. 

The group name is intended to cover esters derived from sulfenic, sulfinic and sulfonic acids, some of which are thermally unstable. This is especially so for esters of unsaturated alcohols, which are also liable to polymerise, catalysed by the liberated acids. Individually indexed compounds are ... 

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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