3-Deoxy-3,3-difluoro-<scp>d</scp>-arabinofuranose: First Stereoselective Synthesis and Application in Preparation of <i>g</i><i>em</i>-Difluorinated Sugar Nucleosides
The design and synthesis of gem-difluorinated sugar nucleosides were described. The key intermediate, 3-deoxy-3,3-difluoro-d-arabinofuranose 9, was first stereoselectively prepared from the chiral gem-difluorohomoallyl alcohol 12. The kinetic formation of single anti-14 in the benzylation of 12 could be accomplished by controlling the amount of sodium hydride used. The dihydroxylation of 14 (a mixture