Abstract Efficient synthesis of 3-deoxy-1, 2-O-isopropylidene-β-d-and β-l-threo- pentofuranose (1, 2-O-isopropylidene-β-d-and β-l-cordycepose) was accomplished starting from d-and l-arabinofuranose derivatives, respectively, by the action of LiBH (Et) 3 on corresponding intermediate 3-O-lyxofuranosyl trifluoromethanesulfonates.