Studies on the diastereoselective oxidation of 1-thio-β-D-glucopyranosides: synthesis of the usually less favoured RS sulfoxide as a single diastereoisomer

A detailed study on the diastereoselective oxidation of 1-thio-β-D-glucopyranosides is reported. It has been shown that the sense and the degree of stereochemical outcome of the oxidation are highly depen- dent on the substituent of the sulfur and on the protective group of the C2–OH. In the case of thioglyco-sides with a bulky aglycone, the mesylation of C2–OH has a significant effect on the stereochemical outcome of the oxidation, affording the usually less favoured RS sulfoxide as a single diastereoisomer. The absolute configuration of the final sulfinyl glycosides was ascertained by NMR analysis and corroborated by X-ray crystallography.Ministerio de Economía y Competitividad CTQ2010-21755-CO2-01, CTQ2010- 21755-CO2-01, CTQ2013-49066-C2-1-R, CTQ2013-49066-C2-2-RJunta de Andalucía P11-FQM-804