Highly stereoselective synthesis of imino-C-di- and trisaccharides as hydrolytically stable glycomimetics

A new straightforward route to glycomimetics containing a piperidine unit is reported. The key step of the methodology is the intramolecular 1,3-dipolar cycloaddition of easily accessible glycosyl alkenyl nitrones. The reaction takes place in most cases with a complete selectivity in favor of the exo–exo adduct, which facilitates the synthesis of all-cis piperidines bearing the glycosyl units. The direct transformation of adducts into the final imino-C-di and trisaccharide analogues is achieved in one step using simple reagents. Inhibition properties against two glycosidases have been tested but no positive results have been found.This study was supported by the Ministerio de Ciencia e Innovación (MICINN) and FEDER Program (Madrid, Spain, project CTQ2010-19606) and the Gobierno de Aragón (Zaragoza, Spain, Bioorganic Chemistry Group. E-10). E.M. thanks MEC for a FPU predoctoral grant.Peer reviewe