Synthesis of Trisaccharides Related to the Branching Region of the O‐Antigen Polysaccharides from
<i>Escherichia coli</i>
O35 and
<i>Salmonella arizona</i>
O62
The synthesis of three trisaccharidesrelated to the branching region in the O-antigen polysaccharides from E. coli O35 and S. arizona O62 is reported. A regioselective β-glycosylation was performed at O-3 of a methyl α-L-rhamnopyranoside derivative. cis-Glycosylation of an α-D-galactosamine derivative at O-2 of the methyl α-L-rhamnopyranoside took place in excellent yield (90%) to produce, after deprotection