A divergent synthesis of D- and L-carbocyclic 4 '-fluoro-2 ',3 '-dideoxynucleosides as potential antiviral agents

D- and L-Carbocyclic 4'-fluoro-2',3'-dideoxynucleosides have been synthesiz ed from 2, which can be conveniently prepared from 1.2:5.6-di-O-isopropylid ene-D-mannitol 1 in eight steps. Ruthenium-catalyzed ring-closing metathesi s has been employed in the synthesis of D-nucleosides, whereas the L-series have been obtained through an intramolecular nucleophilic substitution rea ction. The Mitsunobu condensation was used as a general tool for the synthe sis of both purine and pyrimidine nucleosides. (C) 2001 Elsevier Science Lt d. All rights reserved.