Synthesis of α-d-GlcpNAc-(1→2)-[α-d-ManpNAc-(1→3)-]α-l-Rhap-(1→2)-α-l-Rhap-(1→3)-α-l-Rhap, the repeating unit of O10 antigen from Acinetobacter baumannii

Abstract An efficient synthesis of α- d -Glc p NAc-(1 → 2)-[α- d -Man p NAc-(1 → 3)-]α- l -Rha p -(1 → 2)-α- l -Rha p -(1 → 3)-α- l -Rha p ( 1 ), the repeating unit of the O10 antigen from Acinetobacter baumannii was achieved via sequential assembly of the building blocks, p -methoxylphenyl 2,4-di- O -benzoyl-α- l -rhamnopyranoside ( 2 ); 2- O -allyloxycarbonyl-3,4-di- O -benzoyl-α- l -rhamnopyranosyl trichloroacetimidate ( 3 ); 4-methoxylphenyl 3- O -allyloxycarbonyl-4- O -benzoyl-α- l -rhamnopyranoside ( 4 ); 2-azido-3- O -benzoyl-2-deoxy-4,6- O -isopropylidene-α- d -mannopyranosyl trichloroacetimidate ( 5 ); 2-azido-3,4,6-tri- O -benzoyl-2-deoxy-α,β- d -glucopyrano syl trichloroacetimidate ( 6 ). The total yield of 1 from 4 was 4.7%.