olidine 1-oxides with various 2-substituents into the free diols and, by reduction, into the corresponding pyrrolidinediols (iminoglycitols) is described. The pyrrolidine N-oxides were derived fromD-ribose via unsaturated hydroxylamines, with the key steps of nitrone addition and Cope−House cyclization as described earlier. The biological activity of these compounds with respect to glycosidase inhibition