Surrmary. Several trifluoromethanesulfonyl(TFMS) derivatives of sugars were prepared and treated with sodium in liquid ammonia or subjected to ultraviolet irradiation. Three 3-Q-TFMS derivatives gave the corresponding 3-deoxy compounds, but a P-c-TFMS derivative gave a branched-chain sugar. Recently we reported') the preparation of 3-deoxy sugars by treatment of 3-O-(N N-dimethyl---*sulfamoyl) derivatives with sodium metal in liquid amnonia (Na-NH3). However, the introduction of N,N-dimethylsulfamoyl group to sugars with N,N-dimethylsulfamoyl chloride generally requires ---a strongly basic condition, which often induces undesirable side reactions or deprotection of sugar derivatives. We, therefore, searched for other sulfonyl groups which can easily be introduced. This paper deals with a new radical-type deoxygenation (by Na-NH3 and photolysis) of sugar trifluoromethanesulfonates; the trifluoromethanesulfonyl(TFMS) group is easily introduced under mild conditions and the deoxygenation is successfully performed. The starting TFMS derivatives prepared are methyl 4,6-;-cyclohexylidene-2-deoxy-2-methoxy-carbony1amino-3-~-TFMS-a-I&glucopyranoside (2), 1,2:5,6-di-g-isopropylidene-3-Cl-TFMS-a-L-glucose*) (5), methyl 2-~-acetyl-6-deoxy-6-(~-toluenesulfonylamido)-3-~-TFMS-a-~-glucopyranoside (8) and methyl 6-deoxy-6-(p-toluenesulfonylamido)-2-O-TFMS-a-~-glucopyranoside (11). They were pre-pared from the corresponding hydroxyl precursors (1, 4, 7 and 10) by treatment with trifluoromethanesulfonic anhydride in pyridine (-10Β°C + room temperature) in high yields.