Sulphonyl Ylides

Sulphonyl carbanions react with a variety of carbonyl systems. With isocyanates, methylsulphonyl carbanion underwent a diacylation to afford a diamido-derivative (79), whereas the corresponding sulphinyl carbanion 

Becker and Gosselck have reported the addition of sulphonyl carbanions to dimethylvinylsulphonium ion to give cyclopropanes. Interestingly, the sulphinate ion was not displaced in these reactions. Instead, the initial adduct (83) underwent a proton transfer, converting a sulphonium ylide into a sulphonyl ylide, and the latter apparently 

The chemistry of sulphenes has been reviewed by Field and by Truce and Liu. Fischer has reviewed the preparation of episulphones and olefins by the sulphene route. 

King and Beatson have demonstrated that reverse elimination , the removal of HCl from an a-chlorosulphinic acid, also could be used to 

The phenyl analogue likewise gave a high yield of benzoylethylene. Along the same line, King and Harding have reported a sulpho-Cope rearrangement which appears to involve sulphene formation. Vinyl allyl sulphone, when heated to 170 °C in the liquid phase or to 800 °C in the gas phase, probably was converted into the sulphene (87). In the gas phase, pent-4-enal was isolated, whereas in the liquid phase addition of phenol led to a phenyl sulphonate. 

Sulphonyl ylides usually are obtained by proton removal from a sulphone. Jarvis and Saukaitis have found that the reaction of an a-bromo- or o-chloro-sulphone with triphenylphosphine resulted in abstraction of the halc en and formation of the sulphonyl ylide as an intermediate, which was trapped by protons from the water present. Benzyl phenyl sulphone was converted into the aa-dilithio-carbanion by treatment with n-butyl-lithium in THF-heptane, and Bosworth and M nus have reported that a bicyclic phenylsulphone, upon treatment with n-butyl-lithium and then D2O, was converted into the ao-dideuteriosulphone, and that it was not possible to obtain the mono-deuteriosulphone by that method. Kaiser et al. have found that using sodium, lithium, or potassium amide with dimethyl sulphone or with dibenzyl sulphone resulted in formation of the aa -dicar-banion, as detected by deuteriation or by reaction with benzophenone. Amel and Marek determined the pK. s of a series of phenylphenacyl sulphones and concluded that the sulphone group provided less stabilization for the phenacylide than did a sulphonium group. The p value for substituents on the phenacyl portion was similar to that obtained for sulphonium, phosphonium, arsonium, and pyridinium phenacylides. 

The sulphonyl carbanion (98) could be acylated with acyl chlorides. Similar to an earlier report, phenylsulphonylcyclopropylide was arylated by both acridine and anthracene to afford the 9-cyclopropyl derivatives. The acetylenic carbanion (99) was dialkylated by methyl acrylate, and a Dieckmann condensation occurred in the course of the reaction. Apparently the initial carbanionic intermediate resulting from the Michael-type addition underwent a proton transfer to re-form a sulphonyl ylide, which carried out a second addition. 

Sulphonyl carbanions usually effect a simple addition to carbonyl compounds to afford carbinols, as exemplified by the reaction of (98) with benzaldehyde. The aa -dicarbanions of dimethyl sulphone and dibenzyl sulphone reacted with two moles of benzophenone in a similar manner. 

Jarvis and J. C. Saukaitis, Abstracts of the 163rd meeting, American Chemical Society, 

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The bismuthonium acyl- and sulphonyl-ylides have a completely different appearance and electronic spectra, all of them being yellowish in colour. This is because in their cases, as in those of similar arsonium and stibonium ylides, interaction between an oxygen atom and the bismuth atom is possible, leading to structures such as 48 in accord with this... 

YUdes of Sulphur Selenium, and Tellurium, and Related Structures 315 5 Sulphonyl Ylides... 

The ylide PhI=C(S02CF3)2 was exceptionally stable, melting at 140°C without decomposition. On irradiation in methanol, it gave the ether Me0CH(S02CF3)2 [10] however, this as well as some other photolytic reactions of such ylides with polyfluoroalkyl sulphonyl groups were not confirmed [2],... 

As carbenes react with arsine to give ylides, so nitrenes react to give arsinimines . The nitrenes were generated in situ by copper-catalysed decomposition either of azidesor 3-aryl-l,4,2-dioxazolidin-5-ones N-Ethoxycarbonyl- and iV-p-tolyl-sulphonyl-triphenylarsinimines have been prepared by nitrene capture reactions in which the nitrenes were generated by the action of base on, respectively, a sulphonyloxyurethane and a sulphonamide e.g. equation 44. 

The difference between the ylides (39) and the tetraphenylcyclopentadienylide is that the former, but not the latter, have substituent groups, carbonyl or sulphonyl, which can interact intramolecularly with the antimony or arsenic atom. This interaction has been clearly shown by X-ray crystal structures ... 

Triphenylbismuthonium tetraphenylcyclopentadienylide is stable for some time as a solid but decomposes rapidly in solution it decomposed rapidly when treated with acid or with base. Acyl and sulphonyl bismuthonium ylides are moderately stable, but less so than their arsonium and stibonium analogues some, while stable in solution in inert solvents, decompose when isolation is attempted ... 

Monocyclic Selenophens.—Selenophen has been prepared from butadiene and selenium dioxide. Selenophen-3-malonic esters have been prepared by condensation of l,4-dichlorobut-3-en-2-one with malonic esters followed by reaction with sodium selenide and cyclization. 2-(2-Selenienyl)-3,4-dicarbeth-oxyfuran has been prepared analogously to the thiophen derivative.The transient absorption spectra in the flash photolysis of selenophen have been studied. "" Butyl-lithium and phenyl-lithium attack 2,5-dimethoxyselenophen at the selenium atom, giving dibutyl selenide and diphenyl selenide, respectively, together with some dienes. " Quantitative studies of the acid- and base-catalysed hydrolyses of ethyl selenophen-2-carboxylate, of the reactions of selenophen-2-sulphonyl chloride and of 2-(chloromethyI)selenophen with aniline, and of selenophen-2-carboxaldehyde with aniline and with a phosphorus ylide have been carried out. The results were rationalized by correlation analyses with polar or electrophilic constants of heterocycles, depending on the electron demand of the side-chain. ""... 

There have been several analyses of second-row ylides in which X = S, and Y = N or C. The compounds (96a) and (96b) are both sulphonyl-stabilized sulphur-nitrogen ylides in which there is the possibility of (d )ir bonding between the N and S+ atoms, and also between the N atom and the sulphonyl groups. The dimensions of the two molecules are virtually identical [S+-N 1.636(8) and 1.628(5) A N -S(sulphonyl) 1.591(8) and 1.598(5) A], and both conformations are characterized by non-syn-planar relationships of the onium and anionic-sulphonyl residues. The carbonyl-stabilized sulphur-carbon ylides (97) [S+-C 1.707(5) A C -C(0)... 

Unfortunately, the refinement of the structure of (104) was terminated at a relatively early stage, and it is not possible to use the quoted dimensions for valid comparisons. As with the sulphur ylides, the conclusion which derives from the above analyses is that there is probably Id-pyn bonding both in the P+-N and P+-C- bonds, and also in the N -S(sulphonyl) bond of (102). 

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. 

There have been a number of reports on the photochemical reaction between diazo-compounds and sulphides to form either stable or transient ylides. lllger et al. reported the isolation of a series of ylides from the reaction of dimethyl sulphide with substituted diazomethanes, such substituents being carbonyl, sulphonyl, or phosphoryl groups. Ando et of. described the reaction of diazo dimethyhnalonate with a series of sulphides but found that the yields of ylides varied considerably, much more so than for the thermal reaction, with the nucleophilicity of the sulphide. For example, dimethyl sulphide afforded an 88% yield of ylide (6a) while diphenyl sulphide afforded a 12% yield of ylide (6b). Repetition of the reaction with dimethyl sulphide but in the presence of cyclohexene indicated that the sulphide was about six times as reactive as the olefin toward the photochemically generated carbene. These reactions aU were assumed to occur by conversion of the diazo-compound into a singlet carbene, which attacked sulphur. However, it was found that (6a) also could... 

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