Synthesis and conformational analysis of bicyclic mimics of α- and β-D-glucopyranosides adopting the biologically relevant ²,⁵B conformation.

The synthesis of three conformationally locked d-glucopyranoside analogs displaying the hydroxyl pattern of the parent sugar is described. A two carbon bridge connecting the C-2 and C-5 atoms of the pyranose ring allows a torsion of the sugar ring toward a (2,5)B conformation as confirmed by conformational analysis. This conformation is strongly believed to be adopted by the oxacarbenium ion-like transition state of several inverting glucosidases.
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