title: Evaluation of thioglycosides of Kdo as glycosyl donors.
abstract: The use of Kdo thioglycosides as glycosyl donors using DMTST, IBr/AgOTf and NIS/AgOTf as promoters has been evaluated. Activation at low temperature allowed to escape the formation of 2,3-glycal byproducts to give glycosides in high yield and with good beta-anomeric selectivity. The use of diethyl ether as solvent and (especially) isopropylidene acetals as protecting groups improved the alpha-anomeric selectivity. NIS/AgOTf as promoter surprisingly yielded the 3-iodo-product via the glycal intermediate.
authors.affiliation: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Mannerstedt
authors.forename: Kerstin
authors.initials: K
authors.lastname: Ekelöf
authors.forename: Stefan
authors.initials: S
authors.lastname: Oscarson
mesh_terms: D004220:Disulfides / Q000737:chemistry; D006031:Glycosylation; D008698:Mesylates / Q000737:chemistry; D013400:Sugar Acids / Q000737:chemistry*; D013865:Thioglycosides / Q000737:chemistry*
chemical_list: D004220:Disulfides; D008698:Mesylates; D013400:Sugar Acids; D013865:Thioglycosides; C414104:dimethyl(methylthio)sulfonium; C012077:trifluoromethanesulfonic acid; C120356:3-deoxy-manno-oct-2-ulopyranosonic acid