Partial Substitution of Thioglycosides by Phase Transfer Catalyzed Benzoylation and Benzylation

Partial substitution by phase transfer catalysis giving monobenzoylated and monobenzylated products from 2,3- and from 4,6-diols in ethyl 1-thio-D-hexopyranosides with the β-gluco-, β-galacto- and α-manno-configurations are described. Two disaccharide thioglucoside diols with either the 2′,3′-hydroxyl groups or the 4′,6′-hydroxyl groups free were included in the study. Good yields of monosubstitution products are obtained after chromatographic separations, making this a useful method for obtaining protected thioglycosides with a single hydroxyl group for further manipulations.