Subject sulfinates

Rearrangements involving sulfones have played an important role in the development of the chemistry of sulfones. It is therefore not surprising that all major literature surveys on sulfones1-9, or their sulfinate precursors10-14, also include a discussion of this subject. 

In acid solution an equilibrium (116) similar to (111) also exists for a disulfide and sulfinic acid. The work of Smallcombe and Caserio (1971) discussed earlier has shown that the dico-ordinate sulfur atom in species of the type SR is subject to very rapid nucleophilic attack by sulfides or disulfides so it is hardly surprising that [28] can be readily attacked by a second molecule of disulfide in the fashion shown in (117) (Kice and Morkved, 1964). The dithiosulfonium ion so produced then reacts rapidly with sulfinic acid to form the thiolsulfonate ArSQ2SR (118), a reaction analogous to... 

Thiosemicarbazones, such as 331, and thiourea (333) give rise to sulfinic acids when subjected to photosensitized oxygenation reaction conditions.62,233 It was suggested that by analogy to olefin oxygenation the primary products may be of hydroperoxidic nature... 

Sulfonic Adds, Sulfonic Add Derivatives, and Sulfinic Acids Author Index—Name Readion Index—Subject Index... 

Thiocarbonyl oxides are a subject of active investigation. The natural occurrence of sulfines and related compounds in plants of the genus Allium (onion, garlic, etc.) is included in a superb and extensive review by Block [91]. Two detailed papers [92, 93] report the isolation of zwiebelanes from onions and their chemical synthesis involving intermediate sulfines produced by oxidation of di-l-propenyl disulfide, subsequent sulfoxide accelerated [3.3] sigmatropic shift and the [2+2] cycloaddition of the C=S and C=S=0 moieties. A further article [94] provides a great deal of information on the mechanism of formation of (Z)-propanethial S-oxide, the lachrymatory factor of the onion, as well as its chemical synthesis and reactions. Techniques of analysis of the volatiles of onions have been further improved [95]. 

Chiral sulfoxides are useful intermediates in asymmetric synthesis. A number of methods for their preparation were developed in the last decade. An interesting displacement of dimethylphosphonylmethyl moiety, a carbon leaving group, from sulfur by Grignard reagents was used to obtain enantiomerically purep-tolyl sulfoxides.3 4 Optically pure methyl 4-bromophenyl sulfinate was subjected to a one-pot sequence yielding unsymmetrical dialkyl sulfoxides in 60-97% yield and >98% ee. A simple one-pot synthesis of chiral sulfoxides from norephedrine-derived... 

The alkyls CpMo(CO)3R (R = Me, Et, and CHaPh) readily insert SOa (57) these reactions were the subject of a kinetic study (71, 76). When R = CHaPh, the 0-sulfinato intermediate was detected spectroscopically (72, 73). Contrasting with the above behavior is the apparent lack of reactivity of CpMo(CO)3CFa (57) and CpMo(CO)3CHaCN (124) toward neat SOa- However, the dicarbonyl CpMo(CO)a(PPh3)Me does afford the corresponding >S -sulfinate, the reaction proceeding much more rapidly than that of its parent tricarbonyl, CpMo(CO)3Me (57). The photochemically induced desulfination of CpMo(CO)3S(0)a-CHaPh furnishes CpMo(CO)3CHaPh (35% yield) in contrast, irradiation of CpMo(CO)3S(0)aMe yields [CpMo(CO)3]a (57). 

Vesicants including sulfin" mustard and lewisite are the subject of the second main part of this contribution. Coherences of invasion and distribution are presented and the major processes of metabolism and elimination caused by binding to proteins and more prominently to DNA are discussed. The part closes with comments on current bioanalytical approaches. 

In order to obtain an insight into the diastereoselectivity in the Diels-Alder reaction of acetylenic sulfinates, chiral (+)-trans-2-phenylcyclohexanol [35] was used in place of cyclohexanol in the synthesis of the dienophile. A 1 1 dia-stereoisomeric mixture of acetylenic sulfinates 69 and 70 was obtained. After separation, each diastereoisomer was subjected to a Diels-Alder reaction with cyclopentadiene. Although the reaction once again occurred readily at room temperature, to our disappointment an inseparable mixture of diastereomeric adducts (3 2 by NMR) was obtained for each sulfinate. Apparently, a more spatially demanding chiral auxiliary needs to be incorporated into the dienophile in order to generate chiral sulfinates which cycloadd with prominent diastereoselectivity. 

Carbanions derived from a-sulfonyl ethers 5 undergo [2.3] sigmatropic rearrangement the resulting a-hydroxy sulfoties are subject to a further fragmentation, yielding an aryl sulfinic acid and an aldehyde which reacts further with excess alkyllithium Lo afford a secondary homoallylic alcohol61 66. 

Other electrophilic heterocumulenes (e.g., CS2, RNCO, RNCS, SO2) are also subject to insertion reactions. Accordingly, the insertion of CS2 into the M-N bond in metal dialkylamides produces dithiocarbamate derivatives and the reaction of SO2 with M-C bonds gives sulfinate complexes resulting from either 1,1-insertion [M-0S(0)R] or 1,2-insertion [M-S(R)02]. Rare examples of insertion of dioxygen into Pt-H bonds to generate remarkably stable hydroperoxide derivatives L Pt-OOH have also been reported. 

To a stirred solution of alkene (1 1 mmol) and sodium aryl sulfinate (2 2 mmol) in acetonitrile (10 mL) was added with Kl (10 mol%), Nal04 (10 mol%) and catalytic amount of acetic acid. The resulting reaction mixture was stirred at room temperature for the appropriate time (2.5-7 h as monitored by TLC). After completion of the reaction, the mixture was quenched by the addition of a saturated aqueous solution of sodium thiosulfate (5 mL) and extracted with ethyl acetate (2 X 10 mL). The organic layer was separated and concentrated, and the residue was subjected to column chromatography (silica gel hexane-EtOAc) to obtain the pure product of vinyl sulfone 3. All compounds were characterized based on detailed spectral studies and elemental analyses. 

Dimethyl sulfoxide has been measured in the atmosphere and laboratory studies indicate that in the atmosphere this compound will be rapidly oxidized by reaction with the OH radical. The oxidation of DMSO remains a subject of continued investigation. In the atmosphere, DMSO may be converted into dimethyl sulfone, SO2, or methane sulfinic acid. 

The cycloadducts derived froma-oxo sulfines can be subjected to enzymatic hydrolysis to give optically active esters . Another useful synthetic method involves the transformation of the [4-1-2] cycloadduct 51 into thiabenzenes 52 . 

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