L-pentofuranose derivative(4a) and D-pentofuranose derivative(4b) were synthesized via mesylation, removing isopropylidene group and acetylation with L-ribofuranose (3a) and D-ribofuranose((3b) as starting materials, respectively. Subsequent Vorbruggen coupling with 3-oxo-5,6-dihydropyrazine-2-carboxamide, cyclization, demesylation and debenzylation afforded 7-Hydroxy-1-(hydroxymethyl)-3-[4-(3-oxo-3,4-dihydropyrazine-2-carboxamide)-yl]-2,5-dioxabicyclo[2.2.1] heptane with two different configurations (2a, 2b) in yields 24.6% and 31.5% , respectively. The reaction conditions of ring-closing, demesylation and debenzylation were optimized with yields 83.5%, 62.5% and 86.9%. The chemical structures of target compounds were finely identified by IR, 1H NMR, MS and elementary analysis.