Toluenesulflnic Acid

The best way to prepare large quantities of optically active sulfoxides makes use of optically active menthyl sulfinate. By esterification of p-toluenesulflnic acid with 1-menthol, a mixture of dia-stereoisomeric menthyl sulfinates is obtained. This esterification reaction shows no particular stereoselectivity and therefore a mixture of the two diastereoisomeric esters was obtained. However, it is possible to equilibrate these diastereoisomers in acidic media and to shift the equilibrium towards the... 

The problem of imine hydrolysis can be avoided by cyclising at a lower oxidation level, with tosyl on nitrogen for subsequent elimination as toluenesulflnic acid. The ring closure substrates can be obtained by reduction and tosylation of imine condensation products, "" by benzylating the sodium salt of an... 

It has been proposed that this reaction involves the initial reduction of tosylhydrazone to tosylhydrazine, followed by the elimination of / -toluenesulflnic acid and the decomposition... 

By condensation of the dianion of f-butyl acetoacetate and (—)-menthyl (5)-p-toluenesulflnate, the corresponding 8-keto sulfoxide was obtained in high yield (eq 15) and shown to be an efficient precursor of both enantiomers of 8-hydroxybutyric acid via se-... 

Chiral 7V-benzylidene />toluenesulfinamides were prepared by reaction of benzonitrile with an aUcyllithium followed by addition of (—)-menthyl (5)-p-toluenesulflnate and converted into optically active amines and amino acids (eq 19). ... 

---