Stereocontrolled glycosidations using a heterogeneous solid acid, sulfated zirconia, for the direct syntheses of α- and β-manno- and 2-deoxyglucopyranosides

Novel α- and β-stereocontrolled glycosidations using a heterogeneous solid acid, sulfated zirconia (SO4/ZrO2), as an activator have been developed. The glycosidations of manno- and 2-deoxyglucopyranosyl α-fluorides with several alcohols using SO4/ZrO2 in MeCN proceeded α-stereoselectively, while those with the same activator in the presence of MS 5A in Et2O occurred with β-stereoselectivity. Thus, both the α- and β-manno- and 2-deoxyglucopyranosides were effectively obtained by the present glycosidations.