title: 2,3-Di-O-picolinyl building blocks as glycosyl donors with switchable stereoselectivity.
abstract: 2-O-Picolinyl protected glycosyl donors lead to the formation of 1,2-trans glycosides with complete stereoselectivity. This is due to the participatory effect of the picolinyl nitrogen that is able to block the bottom face of the ring via a six-membered cyclic intermediate. Herein we demonstrate that if the nitrogen atom of the O-picolinyl moiety is temporarily blocked by coordination to the metal center (Pd), it becomes unavailable to participate in glycosylation and hence the stereoselectivity of 2-O-picolinyl-assisted glycosylations can be "switched".
authors.affiliation: Department of Chemistry and Biochemistry, University of Missouri - St. Louis, One University Boulevard, St. Louis, Missouri 63121, USA. demchenkoa@umsl.edu.
authors.forename: Jagodige P
authors.initials: JP
authors.lastname: Yasomanee
authors.forename: Archana R
authors.initials: AR
authors.lastname: Parameswar
authors.forename: Papapida
authors.initials: P
authors.lastname: Pornsuriyasak
authors.forename: Nigam P
authors.initials: NP
authors.lastname: Rath
authors.forename: Alexei V
authors.initials: AV
authors.lastname: Demchenko
mesh_terms: D018360:Crystallography, X-Ray; D006027:Glycosides / Q000138:chemical synthesis / Q000737:chemistry*; D006031:Glycosylation; D008958:Models, Molecular; D010847:Picolines / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D006027:Glycosides; D010847:Picolines