Using stannic chloride, O-glycosidation, especially O-glucuronidation of p-nitrophenol, estradiol 17-acetate, estriol 16,17-diacetate p-nitrobenzyl alcohol, trichloroethanol was carried out. This method is useful for the preparation of some alkyl .alpha.- and .beta.-glucuronosides and aryl .beta.-glucuronosides, especially estrogen derivatives which are obtained in comparatively low yield by the Koenigs-Knorr method. Spectral differences of .alpha.- and .beta.-anomers obtained were examined.