This invention relates to an improved method for stereoselectively
preparing 2 -deoxy-2 ,2 -difluorocytidine of formula (I), which
comprises the steps of reacting a 1-halo ribofuranose compound of formula
(III) with a nucleobase of formula (IV) in a solvent to obtain a
nucleoside of formula (II) with removing the silyl halide of formula (V)
produced during the reaction; and deprotecting the nucleoside of formula
(II) to obtain 2 -deoxy-2 ,2 -difluorocytidine of formula (I).