Molecular asymmetry in sulphites formed from optically active alcohols

Abstract

Non-equivalence of the proton attached to the same carbon as the sulphite group has been observed in sulphites prepared from a series of optically active alcohols, including natural menthol, 5α-cholestan-2β-ol, –4β-ol, and –4α-ol and 5β-cholestan-3α-ol and the methyl and ethyl esters of (S)-(+)-lactic acid.

Racemic butan-2-ol, pentan-2-ol, 3,3-dimethylbutan-2-ol and lactic acid esters gave mixtures of racemic and two meso-isomers. Stereomutation about the sulphur atom was observed in the sulphites prepared from the methyl and ethyl esters of lactic acid, by an alteration in the ratio of meso-isomers as shown by n.m.r. and g.l.c. analyses, after they had been heated for 2 hr. at 200°.