In order to study the structure-activity relationships of L-(~ S,~ S)- and~-(2S, 4R)-dioxolanyl nucleosides as potential anti-HIV agents, various enantiomerically pure L-(~ S,~ S)- and (2S, 4R)-dioxolanylpyrimidine and-purine nucleosides have been synthesized and evaluated against HIV-1 in human peripheral blood mononuclear (PBM) cells. The enantiomerically pure key intermediate 8 has been synthesized in sixsteps from 1, 6-anhydro-8-~-gulose ( ...