title: "Active-latent" thioglycosyl donors and acceptors in oligosaccharide syntheses.
abstract: The fine tuning of thioglycosides used as glycosyl donors occurs through careful manipulations of the aglycon's nucleofugality, for example, by using "active-latent" principles. In the first section, the control of the relative leaving group abilities will be discussed in terms of electronic factors, including electron-donating/withdrawing substituents. In the second section, the nucleofugality will be adjusted by steric factors. Quantitative reactivity relationships will then be documented followed by presentation of other controlling elements including locked conformations, solvents, and promoters that will be illustrated throughout.
authors.affiliation: Pharmaqam - Groupe de Recherche en Chimie Thérapeutique, Université du Québec à Montréal, 8888, Succ. Centre-ville, Montréal, QC, Canada.
authors.forename: Tze Chieh
authors.initials: TC
authors.lastname: Shiao
authors.forename: René
authors.initials: R
authors.lastname: Roy
mesh_terms: D002236:Carbohydrate Conformation; D006031:Glycosylation; D016256:Lewis X Antigen / Q000031:analogs & derivatives; D019158:N-Acetylneuraminic Acid / Q000737:chemistry; D009844:Oligosaccharides / Q000138:chemical synthesis*; D014312:Trisaccharides / Q000138:chemical synthesis
chemical_list: D016256:Lewis X Antigen; D009844:Oligosaccharides; D014312:Trisaccharides; C110530:galactosyl-(1,4)-fucopyranosyl-(1,3)-N-acetylglucosamine; D019158:N-Acetylneuraminic Acid