Stereocontrolled Oligosaccharide Synthesis

The diastereoselective synthesis of β-mannopyranosides has long been recognized as one of the most challenging problems in carbohydrate chemistry. The method developed in our laboratory offers a facile, direct synthesis by means of displacement of the α-mannosyl triflates generated in situ from simple thioglycosides activated by the combination of 1-(benzenesulfinyl) piperidine (BSP) and trifluoromethanesulfonic anhydride in presence of a hindered, non-nucleophilic base 2,4,6-tri-tert-butylpyrimidine (TTBP). Over the years the methodology has achieved a tremendous success as we have synthesized several complex carbohydrate molecules.