1,3-Dipolar cycloadditions of 5-azido-5-deoxy-1,2-O-isopropylidene-α-d-xylofuranose (1) or methyl 5-azido-5-deoxy-2,3-O-isopropylidene-β-d-ribofuranoside (4) with various acetylenes lead in most cases to mixtures of isomeric triazoles, the C-4 substituted product predominating in each case. The d-xylose derivative (10) and d-ribose derivative (12) were used as precursors to reversed nucleoside analogs (16) and (17).