title: Exploring Cooperative Effects in Oxidative NHC Catalysis: Regioselective Acylation of Carbohydrates.
abstract: The utility of oxidative NHC catalysis for both the regioselective and chemoselective functionalization of carbohydrates is explored. Chiral NHCs allow for the highly regioselective oxidative esterification of various carbohydrates using aldehydes as acylation precursors. The transformation was also shown to be amenable to both cis/trans diol isomers, free amino groups, and selective for specific sugar epimers in competition experiments. Efficiency and regioselectivity of the acylation can be improved upon using two different NHC catalysts that act cooperatively. The potential of the method is documented by the regioselective acylation of an amino-linked neodisaccharide.
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstraße 40, 48149, Münster, Germany.
authors.forename: David L
authors.initials: DL
authors.lastname: Cramer
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstraße 40, 48149, Münster, Germany.
authors.forename: Srikrishna
authors.initials: S
authors.lastname: Bera
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstraße 40, 48149, Münster, Germany. studer@uni-muenster.de.
authors.forename: Armido
authors.initials: A
authors.lastname: Studer
mesh_terms: D000215:Acylation; D002241:Carbohydrates / Q000138:chemical synthesis / Q000737:chemistry*; D002384:Catalysis; D004187:Disaccharides / Q000138:chemical synthesis / Q000737:chemistry; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D015394:Molecular Structure; D010084:Oxidation-Reduction
chemical_list: D002241:Carbohydrates; D004187:Disaccharides; C030011:carbene; D008697:Methane
keywords: N-heterocyclic carbene; carbohydrates; cooperative catalysis; organocatalysis; synthetic methods