title: Cooperative catalysis in glycosidation reactions with O-glycosyl trichloroacetimidates as glycosyl donors.
abstract: Thiourea mediates cooperative glycosidation through hydrogen bonding. N,N'-Diarylthiourea as cocatalyst enforces an SN2-type acid-catalyzed glycosidation even at room temperature (see scheme; Bn=benzyl). From O-(α-glycosyl) trichloroacetimidates as glycosyl donors and various acceptors, β-glycosides are preferentially or exclusively obtained.
authors.affiliation: Fachbereich Chemie, Universität Konstanz, Fach 725, 78457 Konstanz (Germany).
authors.forename: Yiqun
authors.initials: Y
authors.lastname: Geng
authors.forename: Amit
authors.initials: A
authors.lastname: Kumar
authors.forename: Hassan M
authors.initials: HM
authors.lastname: Faidallah
authors.forename: Hassan A
authors.initials: HA
authors.lastname: Albar
authors.forename: Ibrahim A
authors.initials: IA
authors.lastname: Mhkalid
authors.forename: Richard R
authors.initials: RR
authors.lastname: Schmidt
mesh_terms: D000081:Acetamides / Q000737:chemistry*; D002384:Catalysis; D062845:Chloroacetates / Q000737:chemistry*; D006031:Glycosylation; D009844:Oligosaccharides / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism; D013890:Thiourea / Q000737:chemistry*
chemical_list: D000081:Acetamides; D062845:Chloroacetates; D009844:Oligosaccharides; D013890:Thiourea; C009528:trichloroacetamide
keywords: acid-base catalysis; cooperativity; glycosylation; organocatalysis; thiourea