title: An unusual glycosylation product from a partially protected fucosyl donor under silver triflate activation conditions.
abstract: Partially protected glycosyl donors are extremely useful reagents for oligosaccharide synthesis allowing more facile deprotection and enhanced activity due to lower steric restraints. A partially protected fucosyl donor containing tert-butyldimethylsilyl (TBDMS) protecting groups was activated under bromine-silver triflate conditions in the presence of primary alcohols and found to give difucoside products exclusively, in good yield with excellent diastereoselectivity. The dimerisation reaction appears to require a conformational relaxation of steric crowding, induced upon activation of the glycosyl donor. The scope and limitations of this unusual glycosylation methodology are reported.
authors.affiliation: School of Chemistry, Trinity Biomedical Sciences Institute, 152-160 Pearse Street, Trinity College, Dublin 2, Ireland. eoin.scanlan@tcd.ie.
authors.forename: Robin
authors.initials: R
authors.lastname: Daly
authors.forename: Eoin M
authors.initials: EM
authors.lastname: Scanlan
mesh_terms: D000438:Alcohols / Q000737:chemistry; D006027:Glycosides / Q000138:chemical synthesis / Q000737:chemistry*; D006031:Glycosylation; D008698:Mesylates / Q000737:chemistry*; D017646:Organosilicon Compounds / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000438:Alcohols; D006027:Glycosides; D008698:Mesylates; D017646:Organosilicon Compounds; C009660:t-butyldimethylsilyl compounds; C012077:trifluoromethanesulfonic acid