Sulphinate anions

These methods involve the polarity reversal of the formerly electrophilic thio reagents, giving the thiolate and sulphinate anions through an electron transfer from the... 

A competition between two strongly activating groups of 1-butyl-sulphonyl-l-chloro-2-p-tolylsulphonylethylene results in the replacement of the p-tolylsulphonyl group by piperidine, sodium sulphide or sodium bisulphite (Backer et al., 1953). It is probable that the extra stabilization of a-chlorine coupled with the differences in basicity of the two sulphinate anions controls the direction of the reaction. 

The effect of a base is to convert the tosylhydrazone (8) into a diazo-alkane (9) and toluene- -sulphinate anion, in an a-elimination process represented by ... 

The formation of the dialkyl (2-oxoalkyl)phosphonates (539) illustrates the regioselec-tive nucleophilic attack by phosphite anion, with rearrangement and displacement of sulphinate anion, applicable when R = C1-C5 alkyl and R = H, Me or Ph in the single case when Ar = Ph, R = H and R = Ph, the product was diethyl (2-phenylethenyl)phospho-... 

In addition to the displacement of sulphinate anions from aryl 2-oxiranyl sulphones recorded earlier, the displacement of nitrite from 2-nitroepoxides by hydrogenphosphonate anions has now been reported . ... 

A new route to sulphenes has been described recently by King and Beatson, who on warming 1-chloroethanesulphinic acid with a base obtained products derived from methylsulphene (129). The latter was considered to be generated by release of chloride ion from the initially formed sulphinate anion. Hence, the authors concluded that the transition state for the reverse process is, by microscopic reversibility, not of impossibly high energy, and they further pointed out that such an abnormal attack on a sulphene must be seriously considered in accounting for the products derived from a sulphene. 

There is little effect of micelles upon the rate of an intramolecular nucleophilic reaction. Micelles of hexadecyltrimethylammonium bromide catalyse, by factors of 10 —10, the arenesulphinate anion-induced hydrolysis of 4-tolylsulphonyl-methyl perchlorate. There is no relationship between the rate acceleration and hydro-phobicity of the sulphinate anion and catalysis is attributed to the concentration of the reactants in the micellar phase.The rate constants for the reaction of nucleophiles with carbonium ions and those for the addition of cyanide ion to the A -alkylpyridinium ions are similar in the micellar and aqueous phases, and the rate enhancement is due to the concentration of reactants in the micellar pseudophase. Similarly, although micellar catalysed dephosphorylation by nucleophiles may show rate enhancements of up to 4 x 10 -fold, the second-order rate constants may be slightly smaller in the micellar pseudophase lowing to its lower polarity. However, the reaction of fluoride ion with 4-nitrophenyldiphenyl phosphate is very rapid in micelles of cetyltrimethylammonium fluoride, but the rate constant continues to increase when the substrate is fully bound with increasing cetyltrimethylammonium fluoride or sodium fluoride. The failure of the micellar pseudophase model is also apparent in the reaction of hydroxide ion with 2,4-dinitrochlorobenzene. It is suggested that reaction occurs between reactants in the aqueous and micellar pseudophases and also between hydroxide ion in water and substrate in the micelle. ... 

The reaction of halogenomethylvinylsulphones with sulphinate anions, termed the Michael-induced Ramberg-Backlund olefin synthesis, represents an interes-... 

Michael addition of sulphonyl carbanions followed by 1,3-elimination of sulphinate anion provides a route to cyclopropanes utilized in the total synthesis of presqualene alcohol, prephytoene alcohol, and the preparation of the simple ketone (74). The palladium complex of an a-sulphonyl carbanion has been reported to add to isolated double bonds. 

Toluene-p-sulphinate anion reacts with chloro-/ -tolylsulphine to give p-methylbenzyl p-tolyl sulphone instead of the expected substitution product, j7-tolyl(toluene-p-sulphonyl)sulphine ... 

As an extension of the reaction of sulphinates with organometallic compounds, the Claisen-type condensation between ketone enolate anions 101 and arenesulphinates may be considered. It was found161,162 that this reaction provides an interesting synthetic approach to a-ketosulphoxides 102 (equation 54 Table 9). 

The neutral sulphur compounds include sulphides or thioethers, disulphides, sulphoxides and sulphones, sulphate and sulphonate esters, and isothiocyanates. Acidic sulphur compounds, i.e. sulphonic and sulphinic acids, thiols and thio-phenols, and the primary sulphonamides have already been discussed. The sulphates of amines are converted by aqueous sodium hydroxide into the free bases the sulphate anion can be detected in the resulting aqueous solution as barium sulphate in the usual manner. 

Excited j -naphtholate has also been used in an anionic photodeprotection of tosylamides. This very mild photodetosylation gives amine and sulphinic acid in the presence of sodium borohydride as a coreductant [178]. This process is even more effective than the photodechlorination described previously since a limiting quantum yield of 0.6 was measured together with a quantitative amine recovery and an almost unchanged naphtholate sensitizer. 

Alternatively, the allyl sulphinyl anion (8) gave the threo adduct (9), which underwent sulphoxide - sulphinate ester rearrangement, leading to the hex-2-enitol derivative (10)(Scheme 4) the threo isomer predominated by non-chelation control, which has previously been difficult to achieve. ... 

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