title: Organocatalytic glycosylation by using electron-deficient pyridinium salts.
abstract: A new organocatalytic glycosylation method based on electron-deficient pyridinium salts is reported. At ambient temperature and catalyst loadings as low as 1 mol %, 2-deoxyglycosides were formed from benzyl- and silyl-protected glycals and primary or secondary glycosyl acceptors, with excellent yields and anomeric selectivity. Mechanistic investigations point to alcohol-pyridinium conjugates (1,2-addition products) as key intermediates in the catalytic cycle.
authors.affiliation: Cologne University, Department of Chemistry, Organic Chemistry, Greinstrasse 4, 50939 Cologne (Germany) http://www.berkessel.de.
authors.forename: Somnath
authors.initials: S
authors.lastname: Das
authors.affiliation: Cologne University, Department of Chemistry, Organic Chemistry, Greinstrasse 4, 50939 Cologne (Germany) http://www.berkessel.de.
authors.forename: Daniel
authors.initials: D
authors.lastname: Pekel
authors.affiliation: Cologne University, Department of Chemistry, Organic Chemistry, Greinstrasse 4, 50939 Cologne (Germany) http://www.berkessel.de.
authors.forename: Jörg-M
authors.initials: JM
authors.lastname: Neudörfl
authors.affiliation: Cologne University, Department of Chemistry, Organic Chemistry, Greinstrasse 4, 50939 Cologne (Germany) http://www.berkessel.de. berkessel@uni-koeln.de.
authors.forename: Albrecht
authors.initials: A
authors.lastname: Berkessel
keywords: acetals; anion binding; glycosylation; organocatalysis; pyridinium cations