D-Glucose, lactose, maltose, and melibiose were benzoylated with Bz2OEt3N reagent to give fully benzoylated b products. Under the same conditions, D-mannose produced a mixture where the b-benzoate predominated. Treatment of the foregoing compounds with EtSH at slightly elevated temperature (5060 C) in the presence of BF3Et2O as a promoter gave the corresponding ethyl 1-thio glycosides in high yields. The a-products predominated in all cases in the anomeric mixtures formed. Individual products of all reactions were isolated by chromatography, they were obtained in analytically pure state, and were fully characterized by 1H and 13C NMR data and physical constants.