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      Metal-Templated Design: Enantioselective Hydrogen-Bond-Driven Catalysis Requiring Only Parts-per-Million Catalyst Loading.

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          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.

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          Author and article information

          Journal
          J. Am. Chem. Soc.
          Journal of the American Chemical Society
          American Chemical Society (ACS)
          1520-5126
          0002-7863
          Jul 20 2016
          : 138
          : 28
          Affiliations
          [1 ] College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, People's Republic of China.
          [2 ] Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana 46556, United States.
          [3 ] Fachbereich Chemie, Philipps-Universität Marburg , Hans-Meerwein-Strasse 4, 35043 Marburg, Germany.
          [4 ] Lab of Computational Chemistry and Drug Discovery, Lab of Chemical Genomics, Peking University Shenzhen Graduate School , Shenzhen 518055, People's Republic of China.
          Article
          10.1021/jacs.6b02769
          27336458
          a8ba4e8a-56da-4d71-bde0-72634ab68ed6
          History

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