Synthesis of Novel Enantiopure Amino- and Azidopyran Building Blocks and Their Click Reactions to Multivalent Carbohydrate Mimetics

Abstract

AbstractThe synthesis of three enantiopure 1,2-oxazine-derived azides was optimized and the reductions of these compounds to amino alcohols were studied. As a primary aim of this study, the copper-catalyzed (3+2)-cycloadditions of the azides were investigated, employing a series of alkynes, dialkynes, and trialkynes, which afforded the corresponding mono-, di-, and trivalent triazole derivatives with different rigid and flexible core elements. The expected click products were generally obtained in good to excellent yields when copper iodide was employed in presence of tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]amine (TBTA) as ligand in acetonitrile at room temperature. Several of the products were subjected to exhaustive hydrogenolysis reactions, leading to enantiopure compounds with aminopyran substructures, which can be regarded as carbohydrate mimetics.