Glycosylation with 2 '-carboxybenzyl glycosides as glycosyl donors: Scope and application to the synthesis of a tetrasaccharide

Glycosylation of 2'-carboxybenzyl (CB) 2,3,4,6-tetra-O-benzyl-alpha-D-mannopyranoside (3), CB 2,3,4,6-tetra-O-benzyl-beta-D-glucopyranoside (4), and CB 2,3-di-O-benzyl-4,6-O-benzylidene-beta-D-glucopyranoside (5) as glycosyl donors with various glycosyl acceptors provided corresponding disaccharides in high yields. The present CB glycoside methodology was successfully applied to the efficient construction of the tetrasaccharide 41.