1
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Pompeo MM, Kelly SM, St-Jean F, Bass TM, Dalton DM, Zell D, Han C, Sirois LE, Gosselin F. Umpolung Flow Chemistry for the Synthesis of a 3-Oxo-3 H-spiro[benzofuran-2,4'-piperidine] Building Block. J Org Chem 2024. [PMID: 38767619 DOI: 10.1021/acs.joc.4c00337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
An efficient and scalable route to tert-butyl 3-oxo-3H-spiro[benzofuran-2,4'-piperidine]-1'-carboxylate, a central prochiral intermediate in the synthesis of SHP2 inhibitor GDC-1971 (migoprotafib), was achieved. Preparation of the title compound from readily available 2-fluorobenzaldehyde included formation of a modified Katritzky benzotriazole hemiaminal, which, upon deprotonation by n-butyllithium, participated in umpolung reactivity via 1,2-addition to tert-butyl 4-oxopiperidine-1-carboxylate (N-Boc-4-piperidone). Most notably, this reaction was developed as a robust plug-flow process that could be executed on multiple kilograms without the need for pilot-scale reaction vessels operating at low cryogenic temperatures. Treatment of the resulting tetrahedral intermediate with oxalic acid resulted in collapse to the corresponding 4-(2-fluorobenzoyl)-4-hydroxypiperidine, which was isolated as a solid via crystallization. The synthesis concluded with an optimized intramolecular SNAr reaction and final crystallization to generate tert-butyl 3-oxo-3H-spiro[benzofuran-2,4'-piperidine]-1'-carboxylate as a stable, high-quality intermediate suitable for further functionalization toward GDC-1971.
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Affiliation(s)
- Matthew M Pompeo
- Department of Synthetic Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Sean M Kelly
- Department of Synthetic Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Frédéric St-Jean
- Department of Synthetic Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Thomas M Bass
- Department of Synthetic Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Derek M Dalton
- Department of Synthetic Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Daniel Zell
- Department of Synthetic Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Chong Han
- Department of Synthetic Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Lauren E Sirois
- Department of Synthetic Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Francis Gosselin
- Department of Synthetic Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
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2
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Lei J, Xu ZG. Reaction strategies for the meta-selective functionalization of pyridine through dearomatization. Mol Divers 2024:10.1007/s11030-024-10861-5. [PMID: 38647989 DOI: 10.1007/s11030-024-10861-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 03/25/2024] [Indexed: 04/25/2024]
Abstract
The pyridine moiety is a crucial structural component in various pharmaceuticals. While the direct ortho- and para-functionalization of pyridines is relatively straightforward, the meta-selective C-H functionalization remains a significant challenge. This review highlights dearomatization strategies as a key area of interest in expanding the application of meta-C-H functionalization of pyridines. Dearomatization enables the meta-functionalization through various catalytic methods that directly generate dearomatization products, and some products can be rearomatized back to pyridine derivatives. Furthermore, this article also covers the dearomatization of multiple positions of pyridine in the synthesis of polycyclic compounds. It offers a comprehensive overview of the latest advancements in dearomatization at different positions of pyridine, aiming to provide a valuable resource for researchers in this field. It also highlights the advantages and limitations of existing technologies, aiming to inform a broader audience about this important field and foster its future development.
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Affiliation(s)
- Jie Lei
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, IATTI, Chongqing University of Arts and Sciences, Chongqing, 402160, China
| | - Zhi-Gang Xu
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, IATTI, Chongqing University of Arts and Sciences, Chongqing, 402160, China.
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3
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Escolano M, Gaviña D, Alzuet-Piña G, Díaz-Oltra S, Sánchez-Roselló M, Pozo CD. Recent Strategies in the Nucleophilic Dearomatization of Pyridines, Quinolines, and Isoquinolines. Chem Rev 2024; 124:1122-1246. [PMID: 38166390 PMCID: PMC10902862 DOI: 10.1021/acs.chemrev.3c00625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
Dearomatization reactions have become fundamental chemical transformations in organic synthesis since they allow for the generation of three-dimensional complexity from two-dimensional precursors, bridging arene feedstocks with alicyclic structures. When those processes are applied to pyridines, quinolines, and isoquinolines, partially or fully saturated nitrogen heterocycles are formed, which are among the most significant structural components of pharmaceuticals and natural products. The inherent challenge of those transformations lies in the low reactivity of heteroaromatic substrates, which makes the dearomatization process thermodynamically unfavorable. Usually, connecting the dearomatization event to the irreversible formation of a strong C-C, C-H, or C-heteroatom bond compensates the energy required to disrupt the aromaticity. This aromaticity breakup normally results in a 1,2- or 1,4-functionalization of the heterocycle. Moreover, the combination of these dearomatization processes with subsequent transformations in tandem or stepwise protocols allows for multiple heterocycle functionalizations, giving access to complex molecular skeletons. The aim of this review, which covers the period from 2016 to 2022, is to update the state of the art of nucleophilic dearomatizations of pyridines, quinolines, and isoquinolines, showing the extraordinary ability of the dearomative methodology in organic synthesis and indicating their limitations and future trends.
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Affiliation(s)
- Marcos Escolano
- Department of Organic Chemistry, Faculty of Pharmacy, University of Valencia, 46100 Burjassot, Valencia, Spain
| | - Daniel Gaviña
- Department of Organic Chemistry, Faculty of Pharmacy, University of Valencia, 46100 Burjassot, Valencia, Spain
| | - Gloria Alzuet-Piña
- Department of Inorganic Chemistry, Faculty of Pharmacy, University of Valencia, 46100 Burjassot, Valencia, Spain
| | - Santiago Díaz-Oltra
- Department of Organic Chemistry, Faculty of Pharmacy, University of Valencia, 46100 Burjassot, Valencia, Spain
| | - María Sánchez-Roselló
- Department of Organic Chemistry, Faculty of Pharmacy, University of Valencia, 46100 Burjassot, Valencia, Spain
| | - Carlos Del Pozo
- Department of Organic Chemistry, Faculty of Pharmacy, University of Valencia, 46100 Burjassot, Valencia, Spain
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4
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Fataj X, Achazi AJ, Rohland P, Schröter E, Muench S, Burges R, Pohl KLH, Mollenhauer D, Hager MD, Schubert US. Development of Novel Redox-Active Organic Materials Based on Benzimidazole, Benzoxazole, and Benzothiazole: A Combined Theoretical and Experimental Screening Approach. Chemistry 2024; 30:e202302979. [PMID: 37950854 DOI: 10.1002/chem.202302979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 10/28/2023] [Accepted: 11/06/2023] [Indexed: 11/13/2023]
Abstract
Sustainability is one of the hot topics of today's research, in particular when it comes to energy-storage systems such as batteries. Redox-active molecules implemented in organic batteries represent a promising alternative to lithium-ion batteries, which partially rely on non-sustainable heavy metal salts. As an alternative, we propose benzothiazole, -oxazole and -imidazole derivatives as redox-active moieties for polymers in organic (radical) batteries. The target molecules were identified by a combination of theoretical and experimental approaches for the investigation of new organic active materials. Herein, we present the synthesis, electrochemical characterization and theoretical investigation of the proposed molecules, which can later be introduced into a polymer backbone and used in organic polymer batteries.
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Affiliation(s)
- Xhesilda Fataj
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstraße 10, 07743, Jena, Germany
- Center for Energy and Environmental Chemistry Jena (CEEC Jena), Friedrich Schiller University Jena, Philosophenweg 7a, 07743, Jena, Germany
| | - Andreas J Achazi
- Institute of Physical Chemistry, Justus-Liebig University Giessen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
- Center for Materials Research, Justus-Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
| | - Philip Rohland
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstraße 10, 07743, Jena, Germany
- Center for Energy and Environmental Chemistry Jena (CEEC Jena), Friedrich Schiller University Jena, Philosophenweg 7a, 07743, Jena, Germany
| | - Erik Schröter
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstraße 10, 07743, Jena, Germany
- Center for Energy and Environmental Chemistry Jena (CEEC Jena), Friedrich Schiller University Jena, Philosophenweg 7a, 07743, Jena, Germany
| | - Simon Muench
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstraße 10, 07743, Jena, Germany
- Center for Energy and Environmental Chemistry Jena (CEEC Jena), Friedrich Schiller University Jena, Philosophenweg 7a, 07743, Jena, Germany
| | - René Burges
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstraße 10, 07743, Jena, Germany
- Center for Energy and Environmental Chemistry Jena (CEEC Jena), Friedrich Schiller University Jena, Philosophenweg 7a, 07743, Jena, Germany
| | - K Linus H Pohl
- Institute of Physical Chemistry, Justus-Liebig University Giessen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
- Center for Materials Research, Justus-Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
| | - Doreen Mollenhauer
- Institute of Physical Chemistry, Justus-Liebig University Giessen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
- Center for Materials Research, Justus-Liebig University Giessen, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
| | - Martin D Hager
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstraße 10, 07743, Jena, Germany
- Center for Energy and Environmental Chemistry Jena (CEEC Jena), Friedrich Schiller University Jena, Philosophenweg 7a, 07743, Jena, Germany
| | - Ulrich S Schubert
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstraße 10, 07743, Jena, Germany
- Center for Energy and Environmental Chemistry Jena (CEEC Jena), Friedrich Schiller University Jena, Philosophenweg 7a, 07743, Jena, Germany
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5
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Kratena N, Marinic B, Donohoe TJ. Recent advances in the dearomative functionalisation of heteroarenes. Chem Sci 2022; 13:14213-14225. [PMID: 36545133 PMCID: PMC9749106 DOI: 10.1039/d2sc04638e] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 11/04/2022] [Indexed: 11/18/2022] Open
Abstract
Dearomatisation reactions of (hetero)arenes have been widely employed as efficient methods to obtain highly substituted saturated cyclic compounds for over a century. In recent years, research in this area has shifted towards effecting additional C-C bond formation during the overall dearomative process. Moving away from classical hydrogenation-based strategies a wide range of reagents were found to be capable of initiating dearomatisation through nucleophilic addition (typically a reduction) or photochemically induced radical addition. The dearomatisation process gives rise to reactive intermediates which can be intercepted in an intra- or intermolecular fashion to deliver products with significantly increased molecular complexity when compared to simple dearomatisation. In this Perspective recent examples and strategies for the dearomative functionalisation of heteroaromatic systems will be discussed.
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Affiliation(s)
- Nicolas Kratena
- Chemistry Research Laboratory, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | - Bruno Marinic
- Chemistry Research Laboratory, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | - Timothy J Donohoe
- Chemistry Research Laboratory, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
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6
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Kischkewitz M, Marinic B, Kratena N, Lai Y, Hepburn HB, Dow M, Christensen KE, Donohoe TJ. Evolution of the Dearomative Functionalization of Activated Quinolines and Isoquinolines: Expansion of the Electrophile Scope. Angew Chem Int Ed Engl 2022; 61:e202204682. [PMID: 35560761 PMCID: PMC9321684 DOI: 10.1002/anie.202204682] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Indexed: 11/09/2022]
Abstract
Herein we disclose a mild protocol for the reductive functionalisation of quinolinium and isoquinolinium salts. The reaction proceeds under transition-metal-free conditions as well as under rhodium catalysis with very low catalyst loadings (0.01 mol %) and uses inexpensive formic acid as the terminal reductant. A wide range of electrophiles, including enones, imides, unsaturated esters and sulfones, β-nitro styrenes and aldehydes are intercepted by the in situ formed enamine species forming a large variety of substituted tetrahydro(iso)quinolines. Electrophiles are incorporated at the C-3 and C-4 position for quinolines and isoquinolines respectively, providing access to substitution patterns which are not favoured in electrophilic or nucleophilic aromatic substitution. Finally, this reactivity was exploited to facilitate three types of annulation reactions, giving rise to complex polycyclic products of a formal [3+3] or [4+2] cycloaddition.
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Affiliation(s)
- Marvin Kischkewitz
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Bruno Marinic
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Nicolas Kratena
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Yonglin Lai
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Hamish B. Hepburn
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Mark Dow
- Chemical Development, Pharmaceutical Technology & DevelopmentOperations, AstraZenecaMacclesfieldSK10 2NAUK
| | - Kirsten E. Christensen
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Timothy J. Donohoe
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
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7
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Kischkewitz M, Marinic B, Kratena N, Lai Y, Hepburn HB, Dow M, Christensen KE, Donohoe TJ. Evolution of the Dearomative Functionalization of Activated Quinolines and Isoquinolines: Expansion of the Electrophile Scope. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 134:e202204682. [PMID: 38505668 PMCID: PMC10946825 DOI: 10.1002/ange.202204682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Indexed: 11/07/2022]
Abstract
Herein we disclose a mild protocol for the reductive functionalisation of quinolinium and isoquinolinium salts. The reaction proceeds under transition-metal-free conditions as well as under rhodium catalysis with very low catalyst loadings (0.01 mol %) and uses inexpensive formic acid as the terminal reductant. A wide range of electrophiles, including enones, imides, unsaturated esters and sulfones, β-nitro styrenes and aldehydes are intercepted by the in situ formed enamine species forming a large variety of substituted tetrahydro(iso)quinolines. Electrophiles are incorporated at the C-3 and C-4 position for quinolines and isoquinolines respectively, providing access to substitution patterns which are not favoured in electrophilic or nucleophilic aromatic substitution. Finally, this reactivity was exploited to facilitate three types of annulation reactions, giving rise to complex polycyclic products of a formal [3+3] or [4+2] cycloaddition.
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Affiliation(s)
- Marvin Kischkewitz
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Bruno Marinic
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Nicolas Kratena
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Yonglin Lai
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Hamish B. Hepburn
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Mark Dow
- Chemical Development, Pharmaceutical Technology & DevelopmentOperations, AstraZenecaMacclesfieldSK10 2NAUK
| | - Kirsten E. Christensen
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Timothy J. Donohoe
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
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8
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Gong L, Zhao H, Yang J, Jiang H, Zhang M. Selective construction of fused heterocycles by an iridium-catalyzed reductive three-component annulation reaction. Chem Commun (Camb) 2021; 57:8292-8295. [PMID: 34318819 DOI: 10.1039/d1cc03332h] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Catalytic conversion of ubiquitously distributed but less reactive N-heteroarenes into functional products remains to date a challenge. Here, through an initial pretreatment of N-heteroarenes with alkyl bromide, we describe a syn-selective construction of functional fused heterocycles via iridium catalyzed reductive annulation of N-heteroarenium salts with formaldehyde and cyclic 1,3-diketones or 4-hydroxycoumarins, proceeding with broad substrate scope, good functional group compatibility, readily available feedstocks, and high step and atom efficiency.
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Affiliation(s)
- Lingzhen Gong
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China.
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9
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Abstract
Interrupted reactions reroute established processes to new and often unanticipated end points. Of particular interest are the cases in which a known reactive intermediate takes on a new reaction pathway, either because this pathway is lower in energy or because the conventional pathway is no longer available. Through analysis of documented cases, we aim to dissect the known interrupted reactions and trace their mechanistic origins. As new chemical processes are being discovered at a seemingly ever-increasing pace, it is likely that new interrupted reactions will continue to emerge. Our hope is that the cases considered in this Review will help identify new classes of these fascinating transformations.
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10
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Marinic B, Hepburn HB, Grozavu A, Dow M, Donohoe TJ. Single point activation of pyridines enables reductive hydroxymethylation. Chem Sci 2020; 12:742-746. [PMID: 34163807 PMCID: PMC8178984 DOI: 10.1039/d0sc05656a] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The single point activation of pyridines, using an electron-deficient benzyl group, facilitates the ruthenium-catalysed dearomative functionalisation of a range of electronically diverse pyridine derivatives. This transformation delivers hydroxymethylated piperidines in good yields, allowing rapid access to medicinally relevant small heterocycles. A noteworthy feature of this work is that paraformaldehyde acts as both a hydride donor and an electrophile in the reaction, enabling the use of cheap and readily available feedstock chemicals. Removal of the activating group can be achieved readily, furnishing the free NH compound in only 2 steps. The synthetic utility of the method was illustrated with a synthesis of (±)-Paroxetine. Pyridines can be activated at a single point with a new benzyl group, followed by dearomative functionalisation at C3 using formaldehyde.![]()
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Affiliation(s)
- Bruno Marinic
- Chemistry Research Laboratory, University of Oxford Mansfield Road Oxford OX1 3TA UK
| | - Hamish B Hepburn
- Chemistry Research Laboratory, University of Oxford Mansfield Road Oxford OX1 3TA UK
| | - Alexandru Grozavu
- Chemistry Research Laboratory, University of Oxford Mansfield Road Oxford OX1 3TA UK
| | - Mark Dow
- AstraZeneca Silk Road Macclesfield SK10 2NA UK
| | - Timothy J Donohoe
- Chemistry Research Laboratory, University of Oxford Mansfield Road Oxford OX1 3TA UK
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11
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Grozavu A, Hepburn HB, Bailey EP, Lindsay-Scott PJ, Donohoe TJ. Rhodium catalysed C-3/5 methylation of pyridines using temporary dearomatisation. Chem Sci 2020; 11:8595-8599. [PMID: 34123119 PMCID: PMC8163342 DOI: 10.1039/d0sc02759f] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Pyridines are ubiquitous aromatic rings used in organic chemistry and are crucial elements of the drug discovery process. Herein we describe a new catalytic method that directly introduces a methyl group onto the aromatic ring; this new reaction is related to hydrogen borrowing, and is notable for its use of the feedstock chemicals methanol and formaldehyde as the key reagents. Conceptually, the C-3/5 methylation of pyridines was accomplished by exploiting the interface between aromatic and non-aromatic compounds, and this allows an oscillating reactivity pattern to emerge whereby normally electrophilic aromatic compounds become nucleophilic in the reaction after activation by reduction. Thus, a set of C-4 functionalised pyridines can be mono or doubly methylated at the C-3/5 positions. Electron poor pyridines can be activated by reduction and then methylated at C3/5 using formaldehyde.![]()
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Affiliation(s)
- Alexandru Grozavu
- Chemistry Research Laboratory, University of Oxford Oxford OX1 3TA UK
| | - Hamish B Hepburn
- Chemistry Research Laboratory, University of Oxford Oxford OX1 3TA UK
| | - Elliot P Bailey
- Chemistry Research Laboratory, University of Oxford Oxford OX1 3TA UK
| | | | - Timothy J Donohoe
- Chemistry Research Laboratory, University of Oxford Oxford OX1 3TA UK
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12
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Abstract
The activation of pyridinium salts with electron-withdrawing heterocycles enables an iridium-catalyzed reductive hydroxymethylation reaction to proceed smoothly, facilitating the preparation of useful 3D heteroaryl-substituted functionalized piperidines. The methodology is used to prepare 3-hydroxymethylated analogues of pharmaceutical agents. Mechanistically, formaldehyde acts as both a hydride donor and the electrophile, leading to the formation of two new carbon-hydrogen bonds and one new carbon-carbon bond under relatively mild conditions.
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Affiliation(s)
- Hamish B Hepburn
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK
| | - Timothy J Donohoe
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK
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