Epoxidation and Bis-hydroxylation of C-Phenyl-∆^2,3-glycopyranosides

Abstract: Epoxidation and cis-hydroxylation of C-phenyl-∆^2,3-glycopyranosides have beencarried out with a view to developing C-aryl glycoside synthesis. Epoxidation of (2,3- and (6-O-tert-butyldimethylsilyl-2,3-dideoxy-D-erythro-hex-2-enopyranosyl)benzenedideoxy-D-erythro-hex-2-enopyranosyl)benzene gave predominantly the allo-adductswhatever the configuration at the anomeric center. Epoxidation of (4,6-di-O-tert-butyl-dimethylsilyl-2,3-dideoxy-D-erythro-hex-2-enopyranosyl)benzene gave the manno- andallo-adducts in a 89:11 and 40:60 ratios for the α- and β-anomers, respectively.Hydroxylation of α-C-phenyl-∆^2,3-glycopyranosides using OsO4 afforded the manno-adductonly, whatever the substituents at positions 4 and 6, whereas hydroxylation of (2,3-dideoxy-β-D-erythro-hex-2-enopyranosyl)benzene and (4,6-di-O-tert-butyldimethylsilyl-2,3-dideoxy- β-D-erythro-hex-2-enopyranosyl)benzene gave the manno- and allo-adducts in25:75 and 80:20 ratios, respectively.