title: Metal-Templated Design: Enantioselective Hydrogen-Bond-Driven Catalysis Requiring Only Parts-per-Million Catalyst Loading.
abstract: Based on a metal-templated approach using a rigid and globular structural scaffold in the form of a bis-cyclometalated octahedral iridium complex, an exceptionally active hydrogen-bond-mediated asymmetric catalyst was developed and its mode of action investigated by crystallography, NMR, computation, kinetic experiments, comparison with a rhodium congener, and reactions in the presence of competing H-bond donors and acceptors. Relying exclusively on weak forces, the enantioselective conjugate reduction of nitroalkenes can be executed at catalyst loadings as low as 0.004 mol% (40 ppm), representing turnover numbers of up to 20 250. A rate acceleration by the catalyst of 2.5 × 10(5) was determined. The origin of the catalysis is traced to an effective stabilization of developing charges in the transition state by carefully orchestrated hydrogen-bonding and van der Waals interactions between catalyst and substrates. This study demonstrates that the proficiency of asymmetric catalysis merely driven by hydrogen-bonding and van der Waals interactions can rival traditional activation through direct transition metal coordination of the substrate.
authors.affiliation: College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, People's Republic of China.
authors.forename: Weici
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana 46556, United States.
authors.forename: Marcus
authors.initials: M
authors.lastname: Arieno
authors.affiliation: Fachbereich Chemie, Philipps-Universität Marburg , Hans-Meerwein-Strasse 4, 35043 Marburg, Germany.
authors.forename: Henrik
authors.initials: H
authors.lastname: Löw
authors.affiliation: College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, People's Republic of China.
authors.forename: Kaifang
authors.initials: K
authors.lastname: Huang
authors.affiliation: Fachbereich Chemie, Philipps-Universität Marburg , Hans-Meerwein-Strasse 4, 35043 Marburg, Germany.
authors.forename: Xiulan
authors.initials: X
authors.lastname: Xie
authors.affiliation: Fachbereich Chemie, Philipps-Universität Marburg , Hans-Meerwein-Strasse 4, 35043 Marburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Cruchter
authors.affiliation: College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, People's Republic of China.
authors.forename: Qiao
authors.initials: Q
authors.lastname: Ma
authors.affiliation: College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, People's Republic of China.
authors.forename: Jianwei
authors.initials: J
authors.lastname: Xi
authors.affiliation: College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, People's Republic of China.
authors.forename: Biao
authors.initials: B
authors.lastname: Huang
authors.affiliation: Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana 46556, United States.|Lab of Computational Chemistry and Drug Discovery, Lab of Chemical Genomics, Peking University Shenzhen Graduate School , Shenzhen 518055, People's Republic of China.
authors.forename: Olaf
authors.initials: O
authors.lastname: Wiest
authors.affiliation: College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Gong
authors.affiliation: College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, People's Republic of China.|Fachbereich Chemie, Philipps-Universität Marburg , Hans-Meerwein-Strasse 4, 35043 Marburg, Germany.
authors.forename: Eric
authors.initials: E
authors.lastname: Meggers
mesh_terms: D002384:Catalysis; D006860:Hydrogen Bonding; D007495:Iridium / Q000737:chemistry*; D007700:Kinetics; D008958:Models, Molecular; D008968:Molecular Conformation
chemical_list: D007495:Iridium