title: Stereoselective tris-glycosylation to introduce beta-(1-->3)-branches into gentiotetraose for the concise synthesis of phytoalexin-elicitor heptaglucoside.
abstract: Dodecyl thioglycosides (3, 4, 5) were prepared by conventional transformation of d-glucose and used as new glycosyl donors for a short-step synthesis of phytoalexin elicitor heptaglucoside. A gentio-tetraoside derivative (6) having three hydroxyl groups was synthesized by NIS-TfOH promoted glycosylate in more than 90% yield followed by selective removal of temporary protective groups. Undesired formation of alpha-glycosides at the introduction of beta-(1-->3)-branches into gentio-oligosaccharides was found to be suppressed by use of a thiophilic reagent system, BSP (1-benzenesulfinyl piperidine)-Tf2O, giving the heptaglucoside in only four glycosylation steps.
authors.affiliation: Division of Environment Materials Science, Graduate School of Environmental Science, Hokkaido University, Kita-ku, Sapporo 060-0810, Japan.
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Son
authors.forename: Chiharu
authors.initials: C
authors.lastname: Tano
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Furukawa
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Furuike
authors.forename: Nobuo
authors.initials: N
authors.lastname: Sakairi
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005936:Glucans / Q000138:chemical synthesis* / Q000737:chemistry; D006027:Glycosides / Q000737:chemistry*; D006031:Glycosylation; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry*; D012717:Sesquiterpenes; D013237:Stereoisomerism; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013729:Terpenes / Q000737:chemistry*; D000094162:Phytoalexins
chemical_list: D005936:Glucans; D006027:Glycosides; D009844:Oligosaccharides; D012717:Sesquiterpenes; D013438:Sulfhydryl Compounds; D013729:Terpenes; C073685:heptaglucoside; D000094162:Phytoalexins