Two trisaccharides, a-D-Galp-(1->3)-b-D-ManpNAc-(1->4)-b-D-Glcp and a-D-Glcp-(1->3)-b-D-ManpNAc-(1->4)-b-D-Glcp, corresponding to structures from Streptococcus pneumoniae capsular polysaccharides type 9A, L, V and type 9N, resp., have been synthesized as 2-aminoethyl glycosides and as protected TMSE glycosides. Et thioglycosides were used as glycosyl donors and NIS/TfOH (in CH2Cl2 for b-linkages) and DMTST (in Et2O for a-linkages) as promoters in the glycosylations. The b-ManNAc motif was introduced at the disaccharide level by azide displacement of a 2-O-triflate with b-D-gluco configuration. The protecting group patterns allow continued syntheses of larger structures. [on SciFinder (R)]