Asymmetric 1,3-dipolar cycloadditions of chiral azomethine ylides to 3-benzyloxy-substituted alkenoylcamphorsultams are described. trans-3,4-Disubstituted pyrrolidines containing a protected hydroxyl group at C(4) of the pyrrolidine ring are obtained in high diastereomeric ratios. Such compounds can serve as chiral building blocks for the syntheses of enantiopure bioactive pyrrolidines. This is exemplified by a short synthetic route to a known glycosidase inhibitor, (3R,4R)-4-(hydroxymethyl)pyrrolidin-3-ol and its enantiomer.