stereoselective synthesis of the novel 4-(β-D-ribofuranosyl)imidazole 5 was accomplished in 4 steps and 85% overall yield from protected D-ribose 1. Cyclization of the diol (RS)-3 having an intact imidazole by modifiedMitsunobu reaction exclusively afforded benzylated β-ribofuranosylimidazole β-4a, accompanied by α-4a, in a ratio of 26:1. Reductive debenzylation completed the synthesis. 2′-Deoxy derivative