Trimethylsilylnitrate−Trimethylsilyl Azide:  A Novel Reagent System for the Synthesis of 2-Deoxyglycosyl Azides from Glycals. Application in the Synthesis of 2-Deoxy-β-N-glycopeptides

A novel reagent system comprising Me3SiN3 and 20 mol % of Me3SiONO2 permits conversion of glycals to 1-azido 2-deoxy sugars in one step in fair to good yields. Galactals offer higher stereoselectivities than do the glucals. Reduction of the azide group with Ph3P−H2O to amino functionality followed by coupling with amino acids leads to the synthesis of novel 2-deoxy-β-N-glycopeptides irrespective of the geometry of initial azido sugars. Using this protocol, a new γ-sugar amino acid derivative is also procured.