Priyanka Gupta, Gabriele Hierlmeier, Carina Baete, Matthew V. Pecoraro, Paolo Tosatti, Kurt Puentener, Paul J. Chirik
{"title":"钼催化剂的萘不对称加氢反应:配体设计提高化学选择性","authors":"Priyanka Gupta, Gabriele Hierlmeier, Carina Baete, Matthew V. Pecoraro, Paolo Tosatti, Kurt Puentener, Paul J. Chirik","doi":"10.1021/acscatal.4c04620","DOIUrl":null,"url":null,"abstract":"The asymmetric hydrogenation of substituted naphthalenes with a series of highly enantioenriched oxazoline imino(pyridine) (OIP) molybdenum cyclooctadiene precatalysts is described. The chemoselectivity of the hydrogenation for the formation of tetralin versus decalin products was systematically explored as a function of the aniline substituents on the molybdenum precatalysts. Examples with 2,6-disubstitution with methyl, ethyl, or iso-propyl substituents were the most active but produced near equimolar mixtures of tetralins and decalins, both with high enantiomeric excesses. Introduction of anilines with either 2-<i>tert</i>-butyl or 2,5-di-<i>tert</i>-butyl substituents increased the selectivity for decalin formation albeit with reduced overall hydrogenation activity. In all cases with 2,6-disubtituted naphthalenes, high enantiomeric excesses are observed. Mechanistic studies demonstrated that [(OIP)Mo] catalysts are inactive for tetralin hydrogenation and analysis of the catalytic reactions by NMR spectroscopy, in combination with independent synthesis, identified (OIP)Mo(η<sup>6</sup>-naphthalene) complexes as the catalyst resting states. Assaying product selectivity as a function of catalyst loading established that increasing the amount of molybdenum precatalyst increased the selectivity for decalin formation. Substrate concentration studies were also conducted and support a pathway whereby tetralin formation arises from displacement of the arene from the coordination sphere of the molybdenum by incoming substrate. These studies establish general design principals for [(OIP)Mo] arene hydrogenation catalysts where larger 2,6-aniline substituents increase activity, likely by promoting η<sup>6</sup> to η<sup>4</sup> haptotropic rearrangement from the arene resting state, while single <i>tert</i>-butyl substitution promotes more selective hydrogenation to decalin products.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":11.3000,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Asymmetric Hydrogenation of Naphthalenes with Molybdenum Catalysts: Ligand Design Improves Chemoselectivity\",\"authors\":\"Priyanka Gupta, Gabriele Hierlmeier, Carina Baete, Matthew V. Pecoraro, Paolo Tosatti, Kurt Puentener, Paul J. Chirik\",\"doi\":\"10.1021/acscatal.4c04620\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The asymmetric hydrogenation of substituted naphthalenes with a series of highly enantioenriched oxazoline imino(pyridine) (OIP) molybdenum cyclooctadiene precatalysts is described. The chemoselectivity of the hydrogenation for the formation of tetralin versus decalin products was systematically explored as a function of the aniline substituents on the molybdenum precatalysts. Examples with 2,6-disubstitution with methyl, ethyl, or iso-propyl substituents were the most active but produced near equimolar mixtures of tetralins and decalins, both with high enantiomeric excesses. Introduction of anilines with either 2-<i>tert</i>-butyl or 2,5-di-<i>tert</i>-butyl substituents increased the selectivity for decalin formation albeit with reduced overall hydrogenation activity. In all cases with 2,6-disubtituted naphthalenes, high enantiomeric excesses are observed. Mechanistic studies demonstrated that [(OIP)Mo] catalysts are inactive for tetralin hydrogenation and analysis of the catalytic reactions by NMR spectroscopy, in combination with independent synthesis, identified (OIP)Mo(η<sup>6</sup>-naphthalene) complexes as the catalyst resting states. Assaying product selectivity as a function of catalyst loading established that increasing the amount of molybdenum precatalyst increased the selectivity for decalin formation. Substrate concentration studies were also conducted and support a pathway whereby tetralin formation arises from displacement of the arene from the coordination sphere of the molybdenum by incoming substrate. 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Asymmetric Hydrogenation of Naphthalenes with Molybdenum Catalysts: Ligand Design Improves Chemoselectivity
The asymmetric hydrogenation of substituted naphthalenes with a series of highly enantioenriched oxazoline imino(pyridine) (OIP) molybdenum cyclooctadiene precatalysts is described. The chemoselectivity of the hydrogenation for the formation of tetralin versus decalin products was systematically explored as a function of the aniline substituents on the molybdenum precatalysts. Examples with 2,6-disubstitution with methyl, ethyl, or iso-propyl substituents were the most active but produced near equimolar mixtures of tetralins and decalins, both with high enantiomeric excesses. Introduction of anilines with either 2-tert-butyl or 2,5-di-tert-butyl substituents increased the selectivity for decalin formation albeit with reduced overall hydrogenation activity. In all cases with 2,6-disubtituted naphthalenes, high enantiomeric excesses are observed. Mechanistic studies demonstrated that [(OIP)Mo] catalysts are inactive for tetralin hydrogenation and analysis of the catalytic reactions by NMR spectroscopy, in combination with independent synthesis, identified (OIP)Mo(η6-naphthalene) complexes as the catalyst resting states. Assaying product selectivity as a function of catalyst loading established that increasing the amount of molybdenum precatalyst increased the selectivity for decalin formation. Substrate concentration studies were also conducted and support a pathway whereby tetralin formation arises from displacement of the arene from the coordination sphere of the molybdenum by incoming substrate. These studies establish general design principals for [(OIP)Mo] arene hydrogenation catalysts where larger 2,6-aniline substituents increase activity, likely by promoting η6 to η4 haptotropic rearrangement from the arene resting state, while single tert-butyl substitution promotes more selective hydrogenation to decalin products.
期刊介绍:
ACS Catalysis is an esteemed journal that publishes original research in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. It offers broad coverage across diverse areas such as life sciences, organometallics and synthesis, photochemistry and electrochemistry, drug discovery and synthesis, materials science, environmental protection, polymer discovery and synthesis, and energy and fuels.
The scope of the journal is to showcase innovative work in various aspects of catalysis. This includes new reactions and novel synthetic approaches utilizing known catalysts, the discovery or modification of new catalysts, elucidation of catalytic mechanisms through cutting-edge investigations, practical enhancements of existing processes, as well as conceptual advances in the field. Contributions to ACS Catalysis can encompass both experimental and theoretical research focused on catalytic molecules, macromolecules, and materials that exhibit catalytic turnover.