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Borden O, Joseph BT, Head MC, Ammons OA, Kim DE, Bonino AC, Keith JM, Chianese AR. Highly Enantiomerically Enriched Secondary Alcohols via Epoxide Hydrogenolysis. Organometallics 2024; 43:1490-1501. [PMID: 38993820 PMCID: PMC11234370 DOI: 10.1021/acs.organomet.4c00214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 06/04/2024] [Accepted: 06/07/2024] [Indexed: 07/13/2024]
Abstract
In this article, we report the development of ruthenium-catalyzed hydrogenolysis of epoxides to selectively give the branched (Markovnikov) alcohol products. In contrast to previously reported catalysts, the use of Milstein's PNN-pincer-ruthenium complex at room temperature allows the conversion of enantiomerically enriched epoxides to secondary alcohols without racemization of the product. The catalyst is effective for a range of aryl epoxides, alkyl epoxides, and glycidyl ethers and is the first homogeneous system to selectively promote hydrogenolysis of glycidol to 1,2-propanediol, without loss of enantiomeric purity. A detailed mechanistic study was conducted, including experimental observations of catalyst speciation under catalytically relevant conditions, comprehensive kinetic characterization of the catalytic reaction, and computational analysis via density functional theory. Heterolytic hydrogen cleavage is mediated by the ruthenium center and exogenous alkoxide base. Epoxide ring opening occurs through an opposite-side attack of the ruthenium hydride on the less-hindered epoxide carbon, giving the branched alcohol product selectively.
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Affiliation(s)
- Olivia
J. Borden
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Benjamin T. Joseph
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Marianna C. Head
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Obsidian A. Ammons
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Diane Eun Kim
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Abigail C. Bonino
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Jason M. Keith
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Anthony R. Chianese
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
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Liu F, Cheng Z, Fang Y, Wang X, Zhao L, Rong ZQ. Metal-Catalyst-Controlled Divergent Synthesis of γ-Butyrolactones via Intramolecular Coupling of Epoxides with Alcohols. Org Lett 2023; 25:3618-3622. [PMID: 37184068 DOI: 10.1021/acs.orglett.3c00898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A metal-controlled divergent protocol for the synthesis of α- and β-substituted γ-butyrolactones was developed through intramolecular coupling of epoxides with alcohols. This method provides an efficient and practicable way to afford γ-butyrolactones with good efficiency, excellent regioselectivity, and broad substrate scope.
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Affiliation(s)
- Feipeng Liu
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) and Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an 710072, China
| | - Zifan Cheng
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) and Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an 710072, China
| | - Yiyun Fang
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) and Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an 710072, China
| | - Xuchao Wang
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) and Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an 710072, China
| | - Lingzi Zhao
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) and Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an 710072, China
| | - Zi-Qiang Rong
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) and Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an 710072, China
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Head M, Joseph BT, Keith JM, Chianese AR. The Mechanism of Markovnikov-Selective Epoxide Hydrogenolysis Catalyzed by Ruthenium PNN and PNP Pincer Complexes. Organometallics 2023; 42:347-356. [PMID: 36937786 PMCID: PMC10015984 DOI: 10.1021/acs.organomet.2c00503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Indexed: 03/02/2023]
Abstract
The homogeneous catalysis of epoxide hydrogenolysis to give alcohols has recently received significant attention. Catalyst systems have been developed for the selective formation of either the Markovnikov (branched) or anti-Markovnikov (linear) alcohol product. Thus far, the reported catalysts exhibiting Markovnikov selectivity all feature the potential for Noyori/Shvo-type bifunctional catalysis, with either a RuH/NH or FeH/OH core structure. The proposed mechanisms of epoxide ring-opening have involved cooperative C-O bond hydrogenolysis involving the metal hydride and the acidic pendant group on the ligand, in analogy to the well-documented mechanism of polar double-bond hydrogenation exhibited by catalysts of this type. In this work, we present a combined computational/experimental study of the mechanism of epoxide hydrogenolysis catalyzed by Noyori-type PNP and PNN complexes of ruthenium. We find that, at least for these ruthenium systems, the previously proposed bifunctional pathway for epoxide ring-opening is energetically inaccessible; instead, the ring-opening proceeds through opposite-side nucleophilic attack of the ruthenium hydride on the epoxide carbon, without the involvement of the ligand N-H group. For both catalyst systems, the rate law and overall barrier predicted by density functional theory (DFT) are consistent with the results from kinetic studies.
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Smith MB. The Backbone of Success of P,N-Hybrid Ligands: Some Recent Developments. Molecules 2022; 27:6293. [PMID: 36234830 PMCID: PMC9614609 DOI: 10.3390/molecules27196293] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 09/21/2022] [Accepted: 09/21/2022] [Indexed: 12/03/2022] Open
Abstract
Organophosphorus ligands are an invaluable family of compounds that continue to underpin important roles in disciplines such as coordination chemistry and catalysis. Their success can routinely be traced back to facile tuneability thus enabling a high degree of control over, for example, electronic and steric properties. Diphosphines, phosphorus compounds bearing two separated PIII donor atoms, are also highly valued and impart their own unique features, for example excellent chelating properties upon metal complexation. In many classical ligands of this type, the backbone connectivity has been based on all carbon spacers only but there is growing interest in embedding other donor atoms such as additional nitrogen (-NH-, -NR-) sites. This review will collate some important examples of ligands in this field, illustrate their role as ligands in coordination chemistry and highlight some of their reactivities and applications. It will be shown that incorporation of a nitrogen-based group can impart unusual reactivities and important catalytic applications.
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Affiliation(s)
- Martin B Smith
- Department of Chemistry, Loughborough University, Loughborough, Leics LE11 3TU, UK
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