3-deoxy-3-fluoro-5-S-acetyl-5-thio-d-xylofuranose (1) and selective acetalation gave the desired isopropylidene 5-thioxylopyranose precursor 3. Acetylation and isopropylidene removal followed by benzoylation led to 3-deoxy-3-fluoro-1,2-di-Ο-benzoyl-4-O-acetyl-5'-thio-d-xylopyranose (6). This was condensed with silylated thymine and selectively deacetylated to afford 1-(2'-Ο-benzoyl-3'-deoxy-3'-fluoro-5'-thio-β-d