Sulphinyl Ylides

The substituted sulphoxide (74) could be converted into the carbanion, which then underwent alkylation. Under acidic conditions the sulphinyl group and the methylthio-group could be removed, affording aldehydes in good yield. This reaction serves as a homologation reaction. Sulphinyl ylides also undergo acylation, as illustrated by the reaction of dimsylsodium... 

Sulphinyl ylides react with carbonyl compounds, usually resulting in overall addition to the carbonyl group and formation of hydroxy-sulphoxides. Additional examples have been reported in the past two years. Vig et al. have reported numerous examples of conjugate addition of a sulphinyl ylide (75) to methyl vinyl ketone and other conjugated olefins. These workers were able to remove the sulphinyl group... 

Change of personnel has led to the division of the wide-ranging chapters on thiocarbonyl compounds and on ylides into more manageable parts. In keeping with more recent work, the short sections on sulphines and sulphenes have been confined to the chapter on thiocarbonyl compounds. To avoid possible inconsistencies, the chemistry of sulphonyl, sulphinyl, and sulphenyl carbanions has been largely included in the chapter on ylides. The order of the chapters has been revised so that the chemistry of acyclic sulphur compounds and sulphur-containing functional groups is covered before cyclic systems. 

Sulphinyl ylides, the carbanions obtained from sulphoxides by proton abstraction, continue to be of limited use in organic synthesis but of increasing interest in stereochemical studies. The thioacetal monosulphox-ide (95) could be dialkylated in the presence of n-butyl-lithium, then cleaved with HgCh to afford a ketone. The monoalkylation product could be intercepted readily, thus permitting the effective dialkylation of C=0 and a novel initiated synthesis of ketones. The stereochemistry of the methyla-tion of 4-t-butyl-l-thiacyclohexane oxide depends on the orientation of the sulphoxide oxygen. Using methyl iodide or trideuteriomethyl iodide in the... 

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