UNUSUAL TRANSFORMATIONS OF MONO- AND DISACCHARIDE INTERMEDIATES IN THE SYNTHESIS OF OLIGOSACCHARIDES RELATED TO FRAGMENTS OF THE CAPSULAR POLYSACCHARIDE OF <i>HAEMOPHILUS INFLUENZAE</i> TYPE E

Abstract

In the course of the synthesis of oligosaccharides related to fragments of the capsular polysaccharide of Haemophilus influenzae type e, the transformations of various 2-O-trifluoromethanesulfonate derivatives of β-D-glucopyranosides in reactions with an azide anion was studied. It gives the products of both nucleophilic substitution and a rearrangement of the 6-membered pyranose ring with its contraction to the 5-membered one through (О-5–С-2)-cyclization. Their formation was interpreted for the first time using quantum mechanical calculations.