Synthesis of tetrasaccharide building block of the O-specific polysaccharide of Shigella dysenteriae type 1

Article abstract of DOI:10.1016/S0040-4020(01)88331-9

A glycosyl trichloroacetimidate derivative (1) of the tetrasaccharide α-D-Galp-(1→3)-α-D-GlcpNAc-(1→3)-α-L-Rhap-(1→3)-α-L-Rhap was synthesized in a highly stereoselective, stepwise manner, using methyl 1-thioglycosides of L-rhamnose, 2-azido-2-deoxy-D-glucose and D-galactose, as major intermediates. The protecting group scenario in compound 1 permits regioselective deblocking at its 'non-reducing end' unit. Therefore 1 is a suitable intermediate for the preparation of extended fragments of the title polysaccharide.