Versatile synthesis of rare nucleotide furanoses.

Direct activation of unprotected thioimidoyl furanosides yielded in only one step and few minutes a panel of rare uridine 5'-diphospho-furanoses. Diastereoselectivity of the reaction was tightly connected with reaction time, temperature, and nature of the furanosyl donor. This approach was totally selective since no ring expansion from the initial five-membered ring to the more stable pyranose form was observed.