title: Synthesis of the Tetrasaccharide Repeating Unit from Acinetobacter baumannii Serogroup O18 Capitalizing on Phosphorus-Containing Leaving Groups.
abstract: The first convergent synthesis of the tetrasaccharide repeating unit of the polymeric O antigen isolated from Acinetobacter baumannii serogroup O18 has been achieved. The ManNAcβ1→4Gal and GalNAcβ1→3Gal units were successfully obtained through β-selective glycosylation with 2-azido-4,6-O-benzylidene-2-deoxymannosyl diphenyl phosphate and Tf2NH-promoted glycosylation with 2-acetamido-2-deoxygalactosyl diethyl phosphite, respectively. The disaccharide units could be coupled with the aid of TMSClO4 as an activator of the diphenyl phosphate leaving group, and global deprotection completed the synthesis of the tetrasaccharide.
authors: Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
authors: Ryoichi
authors: R
authors: Arihara
authors: Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
authors: Kosuke
authors: K
authors: Kakita
authors: Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
authors: Kazuhiro
authors: K
authors: Yamada
authors: Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
authors: Seiichi
authors: S
authors: Nakamura
authors: Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
authors: Shunichi
authors: S
authors: Hashimoto
mesh_terms: D040981:Acinetobacter baumannii / Q000737:chemistry*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry*
chemical_list: D009844:Oligosaccharides; D010758:Phosphorus