title: Regioselective polymethylation of α-(1 → 4)-linked mannopyranose oligosaccharides.
abstract: An approach has been developed of the regioselective methylation of α-(1 → 4)-linked mannopyranose oligosaccharides via a four-step methodology. The key reaction involved n-Bu2SnCl2-mediated activation of cis-diols. By tuning protecting groups on the substrates, multiple cis-diols in the substrates were functionalized in a consistent and regioselective manner. Using optimized substrates and reaction conditions, regioselective methylation of di-, tri-, and tetrasaccharide substrates proceeded in isolated yields per cis-diol of 95, 88 and 79%, respectively. The methodology was also applied to functionalize trans-diols in α-cyclodextrin.
authors.affiliation: Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Gunning-Lemieux Chemistry Centre, Edmonton, AB T6G 2G2, Canada.
authors.forename: Li
authors.initials: L
authors.lastname: Xia
authors.forename: Todd L
authors.initials: TL
authors.lastname: Lowary
mesh_terms: D002236:Carbohydrate Conformation; D008358:Mannose / Q000737:chemistry*; D008745:Methylation; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D009844:Oligosaccharides; D008358:Mannose