title: Enantiotopos-selective C-H oxygenation catalyzed by a supramolecular ruthenium complex.
abstract: Spirocyclic oxindoles undergo an enantioselective oxygenation reaction (nine examples; e.r. up to 97:3) upon catalysis by a chiral ruthenium porphyrin complex (1 mol %). The catalyst exhibits a lactam ring, which is responsible for substrate association through hydrogen bonds, and an active ruthenium center, which is in a defined spatial relationship to the oxygenation substrate. DFT calculations illustrate the perfect alignment of the active site with the reactive C-H bond and suggest--in line with the kinetic isotope effect--an oxygen rebound mechanism for the reaction.
authors.affiliation: Lehrstuhl für Organische Chemie I and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstr. 4, 85747 Garching (Germany) http://www.oc1.ch.tum.de/home_en.html.
authors.forename: James R
authors.initials: JR
authors.lastname: Frost
authors.forename: Stefan M
authors.initials: SM
authors.lastname: Huber
authors.forename: Stefan
authors.initials: S
authors.lastname: Breitenlechner
authors.forename: Christoph
authors.initials: C
authors.lastname: Bannwarth
authors.forename: Thorsten
authors.initials: T
authors.lastname: Bach
mesh_terms: D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D006859:Hydrogen / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D002244:Carbon; D012428:Ruthenium; D006859:Hydrogen; D010100:Oxygen
keywords: asymmetric catalysis; enantioselectivity; hydrogen bond; oxygenation; ruthenium