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R Judge N, Logallo A, Hevia E. Main group metal-mediated strategies for C-H and C-F bond activation and functionalisation of fluoroarenes. Chem Sci 2023; 14:11617-11628. [PMID: 37920337 PMCID: PMC10619642 DOI: 10.1039/d3sc03548d] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 09/11/2023] [Indexed: 11/04/2023] Open
Abstract
With fluoroaromatic compounds increasingly employed as scaffolds in agrochemicals and active pharmaceutical ingredients, the development of methods which facilitate regioselective functionalisation of their C-H and C-F bonds is a frontier of modern synthesis. Along with classical lithiation and nucleophilic aromatic substitution protocols, the vast majority of research efforts have focused on transition metal-mediated transformations enabled by the redox versatilities of these systems. Breaking new ground in this area, recent advances in main group metal chemistry have delineated unique ways in which s-block, Al, Ga and Zn metal complexes can activate this important type of fluorinated molecule. Underpinned by chemical cooperativity, these advances include either the use of heterobimetallic complexes where the combined effect of two metals within a single ligand set enables regioselective low polarity C-H metalation; or the use of novel low valent main group metal complexes supported by special stabilising ligands to induce C-F bond activations. Merging these two different approaches, this Perspective provides an overview of the emerging concept of main-group metal mediated C-H/C-F functionalisation of fluoroarenes. Showcasing the untapped potential that these systems can offer in these processes; focus is placed on how special chemical cooperation is established and how the trapping of key reaction intermediates can inform mechanistic understanding.
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Affiliation(s)
- Neil R Judge
- Departement für Chemie, Biochemie und Pharmazie, Universität Bern Switzerland
| | - Alessandra Logallo
- Departement für Chemie, Biochemie und Pharmazie, Universität Bern Switzerland
| | - Eva Hevia
- Departement für Chemie, Biochemie und Pharmazie, Universität Bern Switzerland
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Brouillet EV, Brown SA, Kennedy AR, Rae A, Walton HP, Robertson SD. Atom-economic access to cationic magnesium complexes. Dalton Trans 2023; 52:13332-13338. [PMID: 37671570 DOI: 10.1039/d3dt02669h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
Cationic alkaline-earth complexes attract interest for their enhanced Lewis acidity and reactivity compared with their neutral counterparts. Synthetic protocols to these complexes generally utilize expensive specialized reagents in reactions generating multiple by-products. We have studied a simple ligand transfer approach to these complexes using (NacNac)MgR and ER3 (NacNac = β-diketiminate anion; E = group 13 element; R = aryl/amido anion) which demonstrates high atom economy, opening up the ability to target these species in a more sustainable manner. The success of this methodology is dependent on the identity of the group 13 element with the heavier elements facilitating faster ligand exchange. Furthermore, while this reaction is successful with aromatic ligands such as phenyl and pyrrolyl, the secondary amide piperidide (pip) fails to transfer, which we attribute to the stronger 3-centre-4-electron dimerization interaction of Al2(pip)6.
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Affiliation(s)
- Etienne V Brouillet
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Scott A Brown
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Alan R Kennedy
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Annabel Rae
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Heather P Walton
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Stuart D Robertson
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
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Ju G, Li Y, Zhao Y. Organic photoredox-catalyzed oxidative azolation of unactivated fluoroarenes. Org Biomol Chem 2023; 21:6503-6508. [PMID: 37540014 DOI: 10.1039/d3ob01041d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
Inexpensive and commercially available 2,4,6-triphenylpyrrolium tetrafluoroborate (TPT) is used as an organic photocatalyst for the nucleophilic aromatic substitution of unactivated fluoroarenes with pyrazole derivatives (SNAr) to form azole arenes. The use of organic photoredox catalysis enables the easy operation of this method under mild conditions. Various fluorinated aromatic compounds are suitable electrophiles for this transformation.
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Affiliation(s)
- Guodong Ju
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science Soochow University, Suzhou 215123, PR China.
| | - Yalong Li
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science Soochow University, Suzhou 215123, PR China.
| | - Yingsheng Zhao
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science Soochow University, Suzhou 215123, PR China.
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453000, P. R. China
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Chulsky K, Malahov I, Bawari D, Dobrovetsky R. Metallomimetic Chemistry of a Cationic, Geometrically Constrained Phosphine in the Catalytic Hydrodefluorination and Amination of Ar-F Bonds. J Am Chem Soc 2023; 145:3786-3794. [PMID: 36738474 PMCID: PMC9936586 DOI: 10.1021/jacs.2c13318] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The synthesis, isolation, and reactivity of a cationic, geometrically constrained σ3-P compound in the hexaphenyl-carbodiphosphoranyl-based pincer-type ligand (1+) are reported. 1+ reacts with electron-poor fluoroarenes via an oxidative addition-type reaction of the C-F bond to the PIII-center, yielding new fluorophosphorane-type species (PV). This reactivity of 1+ was used in the catalytic hydrodefluorination of Ar-F bonds with PhSiH3, and in a catalytic C-N bond-forming cross-coupling reactions between fluoroarenes and aminosilanes. Importantly, 1+ in these catalytic reactions closely mimics the mode of action of the transition metal-based catalysts.
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Zeng H, Li H, Li C, Jiang H, Zhu C. Bond Energy Enabled Amines Distinguishing: Chemo-, Regioselective 1,3-Diamination of (Trifluoromethyl)alkenes with Different Amines by Two C(sp3)-F Bonds Cleavage. Org Chem Front 2022. [DOI: 10.1039/d1qo01849c] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The methods to distinguish different amines are rarely investigated. In this manuscript, a bond energy enabled amines distinguishing strategy is reported. With (trifluoromethyl)alkenes as linchpins, a chemo-, regioselective three-component defluorinative...
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Abstract
AbstractThe unique properties of fluorine-containing organic compounds make fluorine substitution attractive for the development of pharmaceuticals and various specialty materials, which have inspired the evolution of diverse C-F bond activation techniques. Although many advances have been made in functionalizations of activated C-F bonds utilizing transition metal complexes, there are fewer approaches available for nonactivated C-F bonds due to the difficulty in oxidative addition of transition metals to the inert C-F bonds. In this regard, using Lewis acid to abstract the fluoride and light/radical initiator to generate the radical intermediate have emerged as powerful tools for activating those inert C-F bonds. Meanwhile, these transition-metal-free processes are greener, economical, and for the pharmaceutical industry, without heavy metal residues. This review provides an overview of recent C-F bond activations and functionalizations under transition-metal-free conditions. The key mechanisms involved are demonstrated and discussed in detail. Finally, a brief discussion on the existing limitations of this field and our perspective are presented.
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Huang D, Wu X. t-BuOK-promoted methylthiolation of aryl fluorides with dimethyldisulfide under transition-metal-free and mild conditions. J Fluor Chem 2021. [DOI: 10.1016/j.jfluchem.2021.109778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Tran VH, La MT, Kang S, Kim HK. Practical direct synthesis of N-aryl-substituted azacycles from N-alkyl protected arylamines using TiCl 4 and DBU. Org Biomol Chem 2021; 18:5008-5016. [PMID: 32573603 DOI: 10.1039/d0ob00880j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A novel transformation of N-alkyl protected arylamines and cyclic ethers into N-aryl substituted azacycles is described. Alkyl groups have been used for the protection of amines in organic syntheses. In this synthesis, N-alkyl protected arylamines were reacted with cyclic ethers in the presence of TiCl4 and DBU, crucial reagents affording five- and six-membered azacycles. In particular, utilization of the novel TiCl4/DBU-mediated reaction allows various N-alkyl protected arylamines such as N-methyl-, N-ethyl-, N-isopropyl, and N-tert-butyl arylamines to be readily converted into N-aryl substituted azacycles in high yields. This practical approach using various N-alkyl arylamines leads to the efficient preparation of azacycles.
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Affiliation(s)
- Van Hieu Tran
- Department of Nuclear Medicine, Molecular Imaging & Therapeutic Medicine Research Center, Jeonbuk National University Medical School and Hospital, Jeonju, 54907, Republic of Korea. and Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, 54907, Republic of Korea
| | - Minh Thanh La
- Department of Nuclear Medicine, Molecular Imaging & Therapeutic Medicine Research Center, Jeonbuk National University Medical School and Hospital, Jeonju, 54907, Republic of Korea. and Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, 54907, Republic of Korea
| | - Soosung Kang
- College of Pharmacy and Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Hee-Kwon Kim
- Department of Nuclear Medicine, Molecular Imaging & Therapeutic Medicine Research Center, Jeonbuk National University Medical School and Hospital, Jeonju, 54907, Republic of Korea. and Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, 54907, Republic of Korea
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Shi W, Zhang J, Zhao F, Wei W, Liang F, Zhang Y, Zhou S. Nucleophilic Aromatic Substitution of Unactivated Aryl Fluorides with Primary Aliphatic Amines by Organic Photoredox Catalysis. Chemistry 2020; 26:14823-14827. [DOI: 10.1002/chem.202002315] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 06/12/2020] [Indexed: 12/13/2022]
Affiliation(s)
- Weimin Shi
- Key Laboratory of Pesticide & Chemical Biology Ministry of Education College of Chemistry CCNU-uOttawa Joint Research Centre Hubei International Scientific and Technological Cooperation Base of, Pesticide and Green Synthesis Central China Normal University 152 Luoyu Road Wuhan Hubei 430079 China
| | - Jingjie Zhang
- Key Laboratory of Pesticide & Chemical Biology Ministry of Education College of Chemistry CCNU-uOttawa Joint Research Centre Hubei International Scientific and Technological Cooperation Base of, Pesticide and Green Synthesis Central China Normal University 152 Luoyu Road Wuhan Hubei 430079 China
| | - Fengqian Zhao
- Key Laboratory of Pesticide & Chemical Biology Ministry of Education College of Chemistry CCNU-uOttawa Joint Research Centre Hubei International Scientific and Technological Cooperation Base of, Pesticide and Green Synthesis Central China Normal University 152 Luoyu Road Wuhan Hubei 430079 China
| | - Wei Wei
- Key Laboratory of Pesticide & Chemical Biology Ministry of Education College of Chemistry CCNU-uOttawa Joint Research Centre Hubei International Scientific and Technological Cooperation Base of, Pesticide and Green Synthesis Central China Normal University 152 Luoyu Road Wuhan Hubei 430079 China
| | - Fang Liang
- Key Laboratory of Pesticide & Chemical Biology Ministry of Education College of Chemistry CCNU-uOttawa Joint Research Centre Hubei International Scientific and Technological Cooperation Base of, Pesticide and Green Synthesis Central China Normal University 152 Luoyu Road Wuhan Hubei 430079 China
| | - Yin Zhang
- Key Laboratory of Pesticide & Chemical Biology Ministry of Education College of Chemistry CCNU-uOttawa Joint Research Centre Hubei International Scientific and Technological Cooperation Base of, Pesticide and Green Synthesis Central China Normal University 152 Luoyu Road Wuhan Hubei 430079 China
| | - Shaolin Zhou
- Key Laboratory of Pesticide & Chemical Biology Ministry of Education College of Chemistry CCNU-uOttawa Joint Research Centre Hubei International Scientific and Technological Cooperation Base of, Pesticide and Green Synthesis Central China Normal University 152 Luoyu Road Wuhan Hubei 430079 China
- College of Materials and Chemical Engineering Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials China Three Gorges University Yichang Hubei 443002 China
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Lim S, Cho H, Jeong J, Jang M, Kim H, Cho SH, Lee E. Cobalt-Catalyzed Defluorosilylation of Aryl Fluorides via Grignard Reagent Formation. Org Lett 2020; 22:7387-7392. [PMID: 32903016 DOI: 10.1021/acs.orglett.0c02752] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Transition-metal-catalyzed transformations of the carbon-fluorine bond not only tackle an interesting problem of challenging bond activation but also offer new synthetic strategies where the relatively inert C-F bond is converted to versatile functional groups. Herein we report a practical cobalt-catalyzed silylation of aryl fluorides that uses a cheap electrophilic silicon source with magnesium. This method is compatible with various silicon sources and can be operated under aerobic conditions. Mechanistic studies support the in situ formation of a Grignard reagent, which is captured by the electrophilic silicon source.
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Affiliation(s)
- Soobin Lim
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Hyungdo Cho
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Jongheon Jeong
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Minjae Jang
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Hyunseok Kim
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Seung Hwan Cho
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
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