title: On orthogonal and selective activation of glycosyl thioimidates and thioglycosides: application to oligosaccharide assembly.
abstract: Discrimination among S-thiazolinyl (STaz), S-benzoxazolyl (SBox), and S-ethyl anomeric leaving groups was achieved by fine-tuning activation conditions. Preferential glycosidation of a certain leaving group is determined neither by the strength of the activating reagent nor by the stability of the leaving group itself; instead, the type of activation plays the key role. The activation conditions established herein were applied to a sequential five-step synthesis of a hexasaccharide using six monosaccharide building blocks equipped with six different leaving groups.
authors.affiliation: Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One University Boulevard, St. Louis, Missouri 63121, USA.
authors.forename: Sophon
authors.initials: S
authors.lastname: Kaeothip
authors.forename: Alexei V
authors.initials: AV
authors.lastname: Demchenko
mesh_terms: D002240:Carbohydrate Sequence; D006027:Glycosides / Q000737:chemistry*; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry*
chemical_list: D006027:Glycosides; D009844:Oligosaccharides