title: A facile regio- and stereoselective synthesis of mannose octasaccharide of the N-glycan in human CD2 and mannose hexasaccharide antigenic factor 13b.
abstract: A highly concise and effective synthesis of the mannose octasaccharide of the N-linked glycan in the adhesion domain of human CD2 was achieved via TMSOTf-promoted selective 6-glycosylation of a trisaccharide 4,6-diol acceptor with a pentasaccharide donor, followed by deprotection. The pentasaccharide was constructed by selective 3,6-diglycosylation of 1,2-O-ethylidene-beta-D-mannopyranose with 2-O-acetyl-3,4,6-tri-O-benzoyl-alpha-D-mannopyranosyl-(1-->2)-3,4,6-tri-O-benzoyl-alpha-D-mannopyranosyl trichloroacetimidate, while the trisaccharide was obtained by selective 3-O-glycosylation of allyl 4,6-O-benzylidene-alpha-D-mannopyranoside with the same disaccharide trichloroacetimidate, followed by debenzylidenation. The mannose hexasaccharide antigenic factor 13b was synthesized by condensation of a trisaccharide donor, 2-O-acetyl-3,4,6-tri-O-benzoyl-alpha-D-mannopyranosyl-(1-->2)-3,4,6-tri-O-benzoyl-alpha-D-mannopyranosyl-(1-->3)-4,6-di-O-acetyl-2-O-benzoyl-alpha-D-mannopyranosyl trichloroacetimidate, with a trisaccharide acceptor, methyl 3,4,6-tri-O-benzoyl-alpha-D-mannopyranosyl-(1-->2)-3,4,6-tri-O-benzoyl-alpha-D-mannopyranosyl-(1-->2)-3,4,6-tri-O-benzoyl-alpha-D-mannopyranoside, followed by deprotection.
authors.affiliation: Research Center for Eco-Environmental Sciences, Academia Sinica, PO Box 2871, 100085, Beijing, China.
authors.forename: Yuliang
authors.initials: Y
authors.lastname: Zhu
authors.forename: Langqiu
authors.initials: L
authors.lastname: Chen
authors.forename: Fanzuo
authors.initials: F
authors.lastname: Kong
mesh_terms: D018801:CD2 Antigens / Q000737:chemistry*; D006023:Glycoproteins / Q000737:chemistry; D006031:Glycosylation; D006801:Humans; D008362:Mannosides / Q000138:chemical synthesis* / Q000737:chemistry; D008968:Molecular Conformation; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D018801:CD2 Antigens; D006023:Glycoproteins; D008362:Mannosides; D009844:Oligosaccharides