title: Efficient Synthesis of the Lewis A Tandem Repeat.
abstract: The convergent synthesis of the Lewis A (Le(a)) tandem repeat is described. The Le(a) tandem repeat is a carbohydrate ligand for a mannose binding protein that shows potent inhibitory activity against carcinoma growth. The Le(a) unit, {β-d-Gal-(1→3)-[α-l-Fuc-(1→4)]-β-d-GlcNAc}, was synthesized by stereoselective nitrile-assisted β-galactosylation with the phenyl 3-O-allyl-2,4,6-tri-O-benzyl-1-thio-β-galactoside, and ether-assisted α-fucosylation with fucosyl (N-phenyl)trifluoroacetimidate. This common Le(a) unit was easily converted to an acceptor and donor in high yields, and the stereoselective assembly of the hexasaccharide and dodecasaccharide as the Le(a) tandem repeat framework was achieved by 2-trichloroacetamido-assisted β-glycosylation and the (N-phenyl)trifluoroacetimidate method.
authors.affiliation: Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan. moon_side_blow@yahoo.co.jp.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kobayashi
authors.affiliation: Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan. aueki@aomori-u.ac.jp.|Institute for Integrated Cell-Material Sciences (WPI Program), Kyoto University, Yoshida-ushinomiya-cho, Sakyo-ku, Kyoto-shi, Kyoto 606-8302, Japan. aueki@aomori-u.ac.jp.|Faculty of Pharmaceutical Sciences, Aomori University, 2-3-1 Kobata, Aomori-shi, Aomori 030-0943, Japan. aueki@aomori-u.ac.jp.
authors.forename: Akiharu
authors.initials: A
authors.lastname: Ueki
authors.affiliation: Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan. gcchann.0213@gmail.com.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Yamaji
authors.affiliation: Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan. namemnayo_nameneko@yahoo.co.jp.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Nagao
authors.affiliation: Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan. aimamura@gifu-u.ac.jp.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Imamura
authors.affiliation: Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan. hando@gifu-u.ac.jp.|Institute for Integrated Cell-Material Sciences (WPI Program), Kyoto University, Yoshida-ushinomiya-cho, Sakyo-ku, Kyoto-shi, Kyoto 606-8302, Japan. hando@gifu-u.ac.jp.
authors.forename: Hiromune
authors.initials: H
authors.lastname: Ando
authors.affiliation: Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan. kiso@gifu-u.ac.jp.|Institute for Integrated Cell-Material Sciences (WPI Program), Kyoto University, Yoshida-ushinomiya-cho, Sakyo-ku, Kyoto-shi, Kyoto 606-8302, Japan. kiso@gifu-u.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Kiso
authors.affiliation: Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan. ishida@gifu-u.ac.jp.
authors.forename: Hideharu
authors.initials: H
authors.lastname: Ishida
mesh_terms: D002240:Carbohydrate Sequence; D066241:Carbon-13 Magnetic Resonance Spectroscopy; D005690:Galactose / Q000737:chemistry; D007983:Lewis Blood Group Antigens; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D066244:Proton Magnetic Resonance Spectroscopy; D021241:Spectrometry, Mass, Electrospray Ionization; D020080:Tandem Repeat Sequences
chemical_list: D007983:Lewis Blood Group Antigens; C494219:Lewis a oligosaccharide; D009844:Oligosaccharides; D005690:Galactose
keywords: Lewis A tandem repeat; convergent synthesis; sugar-binding protein