Participation of Sulfur Occurred During the Mitsunobu Reaction: Synthesis of Novel Isodideoxythionucleosides.

Novel isodideoxythionucleosides have been synthesized from our versatile intermediate, L-4-thioarabitol derivative 5 using the Mitsunobu reaction as a key step. It is found that the sulfur atom of the 4-thiofuranose derivative takes part in the Mitsunobu reaction.