Allylic Azide Rearrangement in Tandem with Huisgen Cycloaddition for Stereoselective Annulation: Synthesis of C-Glycosyl Iminosugars

Allylic azide rearrangement is used. in,tandem with. intramolecular azide-alkene cycloaddition to give a triazoline that when subsequently decomposed in the presence of a nucleophile gives piperidines. The tandem reaction gives two stereocenters that are generated With high control. The formation of-the piperidines required the presence of innate conformational constraint. The-applicability of the annulation reaction is demonstrated by the synthesis iminosugars. A proposal is included to account for the observed stereoselectivity, which is influenced by the precursor structure.