Sultones, unsaturated

Similar transformations are based upon 1,2-thiazine 2,2-dioxides (5-sultones), easily obtained by treating a,/3- or /3,y-unsaturated ketones with acetic anhydride and sulfuric acid. These compounds can be converted subsequently into furans, thiophenes or pyrroles (Scheme 115). 

Thiophenes can be prepared from the sultones of a,j8-unsaturated ketones. From the 8-sultone of pulegone (89), the thiophene (91) has been obtained through reduction with LiAlHi to (90), followed by dehydration of the latter. ... 

Cava and Schlessinger have reported the synthesis of 1,2,3-triphenyl-isoindole (65) in 78% yield from 1,3-diphenylisobenzofuran (68) hy reaction with thionylaniline (69) and boron trifluoride. The mechanism proposed for this remarkable transformation involves reaiTangement of the adduct (70) derived from thionylaniline and the isobenzofuran, to the tricyclic intermediate (71). This presumably collapses to the S-sultam (72), which yields the isoindole (65) upon extrusion of sulfur dioxide. Loss of sulfur dioxide, both from S-sultones and unsaturated S-sultams, is well documented. ... 

Impurities consist of unreacted material, including alkanes and internal or branched alkenes, and other material which can be detected in the neutral oil fraction of AOS. Examination of this fraction also indicates the amount of unhydrolyzed material (sulfonate esters and sultones) and byproducts (secondary alcohols, unsaturated and 2-chloro-y-sultones) in the sample. Salt calculations are made to determine inorganic sulfates and sodium chloride. Determinations for alkalinity, color, and water are required to meet product... 

The amount of residual sulfonate ester remaining after hydrolysis can be determined by a procedure proposed by Martinsson and Nilsson [129], similar to that used to determine total residual saponifiables in neutral oils. Neutrals, including alkanes, alkenes, secondary alcohols, and sultones, as well as the sulfonate esters in the AOS, are isolated by extraction from an aqueous alcoholic solution with petroleum ether. The sulfonate esters are separated from the sultones by chromatography on a silica gel column. Each eluent fraction is subjected to saponification and measured as active matter by MBAS determination measuring the extinction of the trichloromethane solution at 642 nra. (a) Sultones. Connor et al. [130] first reported, in 1975, a very small amount of skin sensitizer, l-unsaturated-l,3-sultone, and 2-chloroalkane-l,3-sultone in the anionic surfactant produced by the sulfation of ethoxylated fatty alcohol. These compounds can also be found in some AOS products consequently, methods of detection are essential. 

Internal sultones, formed from internal alkenes, may also occur. These react less readily than corresponding terminal sultones. In addition, feedstock materials contain alkenes with multiple points of unsaturation, which may form unsaturated sultones such as the unsaturated y-sultone upon sulfonation. 

MacMillan and Wright [133] identified and measured saturated and unsaturated 1,3- and saturated 1,4-sultones in anionic surfactants by a series of separation maneuvers. Ion exchange treatment separates sultones from the bulk of the ionic surfactant. TLC concentrates the sultones systems for HPLC analysis. They found that pentane-ether is preferable to the usual hexane-ether system and that the addition of a little methanol sharpens the separations. Finally, HPLC using a micro-Porasil column with 90 1 isooctane/ethanol provides quali-... 

Although the chlorosultones can be isolated by the same procedure, the isolation is tedious at concentrations below 5 ppm. The chlorosultones are best determined by performing two analyses, one on the intact surfactant and one in which the sultone-containing concentrates are treated with collidine to de-hydrohalogenate the chlorosultones before measurement of the total quantity of unsaturated sultones. 

Numerous stationary phases were investigated by Callahan et al. [135] but only OV-101 separated C14 5-sultone from the C14 unsaturated-y/2-chloro-y-sultone combination and also separated these from other components present in the sample. Apiezon L separated all three sultones of interest but other components in the neutral oil interfered with the C14 unsaturated y-sultone. Additional stationary phases were found which will separate these sultones, but again, interfering components preclude their use for neutral oil analysis. 

A gas chromatographic method is described in this work for the analysis of tetradecane-l,4-sultone (C14 5-sultone) and the combination of 2-chloro-tetradecane-l,3-sultone (C14 2-chloro-y-sultone) and l-tetradecene-l,3-sultone (C14 unsaturated y-sultone) in neutral oils isolated from alkenesulfonate. Samples of the neutral oil are diluted in hexane and injected directly into the gas chromatograph. Quantitative data are obtained by comparison to known amounts of the respective sultones. Through the use of silica gel column chromatography followed by GC of collected fractions, separation and individual quantitation of the 2-chlorotetradecane-l,3-sultone and l-tetradecene-l,3-sultone can be obtained. 

Two-dimensional thin-layer chromatography. This method is used to verify the presence of terminal 5-sultones, terminal unsaturated y-sultone, and terminal 2-chloro-y-sultone, if they are detected in the gas chromatographic determination. After extraction of the neutral oil from the AOS sample, the neutral oil is made up volumetrically to at least a 10% solution in hexane. Of this solution 3 pi is spotted onto a silica gel TLC plate together with standard sultones. It is twice developed with 2-propyl ether and then after turning the plate 90° twice developed with 60/40 n-butyl chloride/methylene chloride. The... 

Synthesis and Diels-Alder reactions of a,/f-unsaturated y-sultone [151]... 

With Sultones. The sultone ring in the unsaturated sultones (LXXI and LXXII) is readily opened by irradiation in methanol with formation of LXXIIIa and LXXIV, respectively.108 Irradiation of LXXI in ether containing benzylamine gave LXXIIIb. 

In the second group the starting molecule belongs to another class of oxygenated heterocycle, such as a coumarin, flavone, chroman, a,fi-unsaturated y-lactone, or S-sultone. 

An analogous ring cleavage reaction has been reported for unsaturated sultones121 for example, the sultone (132) is photo-chemically converted in methanol solution into the methyl sulfonate... 

Later it was found that the result of reaction of unsaturated compounds with S03 strongly depends on the structure of fluoroolefin. While HFP gives p-sultone in a high yield under the action of pure S03 [173], perfluoroallylbenzene reacts with S03 exothermally to give a mixture of /1-sultone and F-phenyl-propenyl fluorosulfate, but 3,3,3-trifluorotrichloropropene-l or 2,3-dichloro-F-butene-2 reacts with S03, forming allyl fluorosulfates 87 or 88 [175,176] ... 

In the former product, the SO3 has added across the unsaturation in the carbon chain, resulting in a saturated alkyl chain, with an internal hydroxyl and sulphonate and a terminal carboxylate. This mechanism probably proceeds via a sultone intermediate, with the final... 

Unsaturated sultones are obtained in high yield through RCM of unsaturated sulfonates using Grubbs Ru catalysts (Scheme 10) <02SL2019>. 

Further results on the highly stereoselective nucleophilic ring-opening of chiral y-sul tones 112 have appeared <07S1837> and the reactions of p-halo-a,p-unsaturated y-sultones 113 with nucleophiles have also been reported <07JOC6824>. 

Further examples of RCM in heteronine synthesis include a variety of 1,2,7-thiadiazonines 261, which can be incorporated into a peptide sequence <2004JOC3662>, and unsaturated nine-membered sultone 262 <2004S1696, 2002SL2019>. 

The unsaturated sultones 82 were also formed from 81 (prepared in turn by esterification of the alcohol 80 with the sulfonyl chloride 79) using Grubbs imidazolidine — based ruthenium catalyst <03SL667>. 

Another example is the conversion of cyclohexene (164) to the bicyclic sultone (165) (Scheme 67). This allows the synthesis of sultones with partially determined stereochemistry. Both reactions depend on the high leaving group properties of the methanesulfoxy anion. Unsaturated 8-sultones like (166) can be obtained by 1,4-cydoaddition of sulfenes (generated in situ) to a,(3-unsaturated carbonyl compounds (Scheme 68). 

Epoxysulfonyl chlorides. Obtained by epoxidation of the unsaturated sulfonyl chlorides the reactive reagents are transformed into cyclic sultones. The hydrolytic instability of the sulfonyl chlorides limits the epoxidizing agent. 

Very recently, a similar bifunctional catalyst system (metal triflates and cinchona alkaloid) was successfully applied by Peters and coworkers for the synthesis of (3-sultones (Scheme 4.17) [40] and chiral a,P-unsaturated 8-lactones [41]. 

Helferich and Klebert58 obtained the 5,6,7,8-tetrahydro-2//-l,2-benzo-thiazine 1,1-dioxide 84 by treating the bicyclic sultone derivative 83 with aniline (Eq. 18). The sultone 83 was readily prepared by reacting the a,/ -unsaturated ketone 82 with sulfuric acid/acetic anhydride. 

Sulfoxide, sulfinate and sulfonate are used as activators of acetylenic or vinyl units. Several a, P unsaturated synthons, namely acetylenic sulfoxide (1), vinyl sulfoxide (2), acetylenic sulfinate (3), acetylenic sulfonate (4), and l-propene-l,3-sultone (5) are developed. Their applications in Diels-Alder reactions, heterocycle and alkaloid syntheses are also investigated. For the chiral acetylenic sulfoxide, the sulfoxide moiety not only enables chemical activation of the acetylene unit, it can also induce stereochemical control at the adjacent carbon centers to achieve enantioselective synthesis. 

Although the chemistry of the saturated propane sultone was investigated in some detail [39], there were only limited reports on the preparation and reaction of the corresponding a, / -unsaturated propane sultone. 

Our approach to the synthesis of the unsaturated y-sultone 5 is depicted in Scheme 16. Sodium 2-propenesulfonate (73) was prepared from allyl bromide and sodium sulfite. Bromination of 73 in water resulted in dibromide 74. Distil-lative cyclization of the dibromide under acidic conditions afforded /3-bromo-sultone 75 which could be eliminated to 5 upon treatment with triethylamine. 

Table 9. Diels-Alder reactions of a, (5 unsaturated propane sultone 75...

Lee AWM, Chan WH, Jiang LS (1996) Chemistry of a, /) unsaturated y-sultone Diels-Alder reactions and synthesis of an optically pure sultam. Presented at the 212th American Chemical Society National Meeting, Orlando... 

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