Organocatalysis by hydrogen bonding networks.
In biological systems, hydrogen bonding is used extensively for molecular recognition, substrate binding, orientation and activation. In organocatalysis, multiple hydrogen bonding by man-made catalysts can effect remarkable accelerations and selectivities as well. The lecture presents four examples of non-enzymatic (but in some cases enzyme-like!) catalysis effected by hydrogen bonding networks: epoxidation of olefins and Baeyer-Villiger oxidation of ketones with H2O2 in fluorinated alcohol solvents; peptide-catalyzed asymmetric epoxidation of enones by H2O2; dynamic kinetic resolution of azlactones, affording enantiomerically pure alpha-amino acids; and kinetic resolution of oxazinones, affording enantiomerically pure beta-amino acids. All four types of transformations are of preparative value, and their mechanisms are discussed.
Berkessel
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Department of Chemistry, University of Cologne, Cologne, Germany. berkessel@uni-koeln.de
D000438:Alcohols / Q000737:chemistry; D000596:Amino Acids / Q000737:chemistry; D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods*; D006860:Hydrogen Bonding; D007700:Kinetics; D008024:Ligands; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D010455:Peptides / Q000737:chemistry; D013237:Stereoisomerism
D000438:Alcohols; D000596:Amino Acids; D008024:Ligands; D008670:Metals; D010455:Peptides