(2-Deoxy-2-fluoro-4-thio-β-d-arabinofuranosyl)thymine (S-FMAU) was synthesized very efficiently from corresponding d-arabinofuranose derivative 16a which was available in bulk. Three important transforming methods were mainly described. One was the practical inversional bromination process for secondary alcohol generated by opening furanose ring. Another was the highly efficient thiofuranose synthesis via intramolecular carbonyl assisted SN2 reaction. And the last was the β-selective glycosylation process with thymine derivative. Applications of the thiofuranose synthesis using intramolecular carbonyl assist were also discussed.
