Stereoselective synthesis by double reductive amination ring closure of novel aza-heteroannulated sugars

We present here the stereoselective synthesis of a series of 2/3-N-pyrrolidine derivatives of glycosides produced by diastereoselective double reductive amination ring closure of 1,4-dicarbonyl compounds. These precursors were produced by tandem ozonolysis–reduction or Wacker oxidation of known alkenes. The potential of these new compounds as glycosidase inhibitors is illustrated for compound 16, showing selective inhibition of β-d-galactosidase.