Synthesis of 4-thiofuranoid 1,2-glycals and their application to stereoselective synthesis of 4′-thionucleosides

Convenient one-pot procedures using iodine monochloride have been developed for the preparation of two 4-thio-1,2-glycals from readily available starting materials and for their β-anomer selective conversion into 2′-iodo-4′-thionucleosides. Conditions for the reductive de-iodination of these iodonucleosides have been established and hence routes to a range of 2′-deoxy-4′-thionucleosides become feasible.