Stereoselective Synthesis of the Hexasaccharide Repeating Unit of the Cell Wall Polysaccharide from Kineosporia aurantiaca VKM Ac-720^T Employing the Direct Glycosylation with Anomeric Hydroxy Sugars Involving Glycosyl Phthalate Intermediates

Abstract

Synthesis of a suitably protected form of the hexasaccharide repeating unit of the cell wall polymer from Kineosporia aurantiaca VKM Ac-720 ^T has been achieved by the stereoselective direct glycosylation of a trisaccharide acceptor with a trisaccharide donor having an anomeric hydroxy group involving a glycosyl phthalate intermediate. Both the trisaccharide acceptor and the trisaccharide donor were obtained from a common trisaccharide, of which two β-mannopyranosyl linkages were constructed stereoselectively by employing the direct glycosylation method with the anomeric hydroxy sugar involving a glycosyl phthalate intermediate and the 2′-carboxybenzyl glycoside method, respectively.

Keywords:

• Oligosaccharides
• Glycosylation
• 2′-Carboxybenzyl (CB) glycosides
• Glycosyl phthalates
• β-Mannosylation

ACKNOWLEDGEMENT

This work was supported by a grant from the Korea Science and Engineering Foundation through the Center for Bioactive Molecule Hybrids (CBMH). S.M.P. and D.-H.S. thank the fellowship of the BK 21 program from the Ministry of Education and Human Resources Development.