Conversion of glycals into vicinal-1,2-diazides and 1,2-(or 2,1)-azidoacetates using hypervalent iodine reagents and Me3SiN3. Application in the synthesis of N-glycopeptides, pseudo-trisaccharides and an iminosugar

Glycals were found to react with a reagent system comprising of phenyliodine bis(trifluoroacetate) (PIFA) and Me3SiN3 in the presence of TMSOTf as a catalyst to form the corresponding vicinal 1,2-diazides. On the other hand, they reacted with another reagent system phenyliodine diacetate (PIDA) and Me3SiN3, also in the presence of TMSOTf as a catalyst, to lead to the corresponding vicinal 1,2-azidoacetates. These azido derivatives were converted into a number of 2-azido-N-glycopeptides, pseudotrisaccharides, and a piperidine triol derivative, an iminosugar.