1
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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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2
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Iwasaki T, Kambe N. Cross- and Multi-Coupling Reactions Using Monofluoroalkanes. CHEM REC 2023; 23:e202300033. [PMID: 37070641 DOI: 10.1002/tcr.202300033] [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: 01/30/2023] [Revised: 04/03/2023] [Indexed: 04/19/2023]
Abstract
Carbon-fluorine bonds are stable and have demonstrated sluggishness against various chemical manipulations. However, selective transformations of C-F bonds can be achieved by developing appropriate conditions as useful synthetic methods in organic chemistry. This review focuses on C-C bond formation at monofluorinated sp3 -hybridized carbons via C-F bond cleavage, including cross-coupling and multi-component coupling reactions. The C-F bond cleavage mechanisms on the sp3 -hybridized carbon centers can be primarily categorized into three types: Lewis acids promoted F atom elimination to generate carbocation intermediates; nucleophilic substitution with metal or carbon nucleophiles supported by the activation of C-F bonds by coordination of Lewis acids; and the cleavage of C-F bonds via a single electron transfer. The characteristic features of alkyl fluorides, in comparison with other (pseudo)halides as promising electrophilic coupling counterparts, are also discussed.
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Affiliation(s)
- Takanori Iwasaki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Nobuaki Kambe
- Research Center for Environmental Preservation, Osaka University, 2-4 Yamadaoka, Suita, Osaka, 565-0871, Japan
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3
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Sheldon DJ, Parr JM, Crimmin MR. Room Temperature Defluorination of Poly(tetrafluoroethylene) by a Magnesium Reagent. J Am Chem Soc 2023; 145:10486-10490. [PMID: 37154713 DOI: 10.1021/jacs.3c02526] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Perfluoroalkyl substances (PFAS) are pervasive in the environment. The largest single use material within the PFAS compound class is poly(tetrafluoroethylene) (PTFE), a robust and chemically resistant polymer. Despite their widespread use and serious concerns about their role as pollutants, methods for repurposing PFAS are rare. Here we show that a nucleophilic magnesium reagent reacts with PTFE at room temperature, generating a molecular magnesium fluoride which is easily separated from the surface-modified polymer. The fluoride in turn can be used to transfer the fluorine atoms to a small array of compounds. This proof-of-concept study demonstrates that the atomic fluorine content of PTFE can be harvested and reused in chemical synthesis.
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Affiliation(s)
- Daniel J Sheldon
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, Shepherds Bush, London, W12 0BZ, U.K
| | - Joseph M Parr
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, Shepherds Bush, London, W12 0BZ, U.K
| | - Mark R Crimmin
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, Shepherds Bush, London, W12 0BZ, U.K
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4
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Jin X, Wang G, Zhou M. Mg(I)-Fe(-II) and Mg(0)-Mg(I) covalent bonding in the Mg nFe(CO) 4- ( n = 1, 2) anion complexes: an infrared photodissociation spectroscopic and theoretical study. Phys Chem Chem Phys 2023; 25:7697-7703. [PMID: 36866694 DOI: 10.1039/d2cp05719k] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Heteronuclear magnesium-iron carbonyl anion complexes MgFe(CO)4- and Mg2Fe(CO)4- are produced in the gas phase and are detected by mass-selected infrared photodissociation spectroscopy in the carbonyl stretching frequency region. The geometric structures and the metal-metal bonding are discussed with the aid of quantum chemical calculations. Both complexes are characterized to have a doublet electronic ground state with C3v symmetry containing a Mg-Fe bond or a Mg-Mg-Fe bonding unit. Bonding analyses indicate that each complex involves an electron-sharing Mg(I)-Fe(-II) σ bond. The Mg2Fe(CO)4- complex involves a relatively weak covalent Mg(0)-Mg(I) σ bond.
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Affiliation(s)
- Xiaoyang Jin
- Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University Shanghai, Shanghai 200438, China.
| | - Guanjun Wang
- Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University Shanghai, Shanghai 200438, China.
| | - Mingfei Zhou
- Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University Shanghai, Shanghai 200438, China.
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5
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Poole EW, Bustos I, Hood TM, Smart JE, Chaplin AB. Iridium complexes of an ortho-trifluoromethylphenyl substituted PONOP pincer ligand. Dalton Trans 2023; 52:1096-1104. [PMID: 36602231 PMCID: PMC9872493 DOI: 10.1039/d2dt03608h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The synthesis and iridium coordination chemistry of a new pyridine-based phosphinito pincer ligand 2,6-(ArF2PO)2C5H3N (PONOP-ArF; ArF = 2-(CF3)C6H4) are described, where the P-donors have ortho-trifluoromethylphenyl substituents. The iridium(III) 2,2'-biphenyl (biph) derivative [Ir(PONOP-ArF)(biph)Cl] was obtained by reaction with [Ir(biph)(COD)Cl]2 (COD = 1,5-cyclooctadiene) and subsequent halide ion abstraction enabled isolation of [Ir(PONOP-ArF)(biph)]+ which features an Ir ← F-C bonding interaction in the solid state. Hydrogenolysis of the biphenyl ligand and formation of [Ir(PONOP-ArF)(H)2]+ was achieved by prolonged reaction of [Ir(PONOP-ArF)(biph)]+ with dihydrogen. This transformation paved the way for isolation and crystallographic characterisation of low valent iridium derivatives through treatment of the dihydride with tert-butylethylene (TBE). The iridium(I) π-complex [Ir(PONOP-ArF)(TBE)]+ is thermally stable but substitution of TBE can be achieved by reaction with carbon monoxide. The solid-state structure of the mono-carbonyl product [Ir(PONOP-ArF)(CO)]+ is notable for an intermolecular anagostic interaction between the metal centre and a pentane molecule which co-crystallises within a cleft defined by two aryl phosphine substituents.
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Affiliation(s)
- Ethan W. Poole
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventry CV4 7ALUK
| | - Itxaso Bustos
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventry CV4 7ALUK,Facultad de Química de San Sebastián, Universidad del País Vasco (UPV/EHU)Apdo. 107220080 San SebastiánSpain
| | - Thomas M. Hood
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventry CV4 7ALUK
| | - Jennifer E. Smart
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventry CV4 7ALUK
| | - Adrian B. Chaplin
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventry CV4 7ALUK
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6
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Burnett S, de Vere-Tucker M, Davitt M, Cordes DB, Slawin AMZ, Ferns R, van Mourik T, Stasch A. Magnesium Complexes with Isomeric Pyrazol‐4‐ylidene and Imidazol‐2‐ylidene Ligands. Z Anorg Allg Chem 2022. [DOI: 10.1002/zaac.202200207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
| | | | | | | | | | | | | | - Andreas Stasch
- University of St Andrews School of Chemistry North Haugh KY169ST St Andrews UNITED KINGDOM
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7
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Sheldon DJ, Crimmin MR. Repurposing of F-gases: challenges and opportunities in fluorine chemistry. Chem Soc Rev 2022; 51:4977-4995. [PMID: 35616085 PMCID: PMC9207706 DOI: 10.1039/d1cs01072g] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Indexed: 11/24/2022]
Abstract
Fluorinated gases (F-gases) are routinely employed as refrigerants, blowing agents, and electrical insulators. These volatile compounds are potent greenhouse gases and consequently their release to the environment creates a significant contribution to global warming. This review article seeks to summarise: (i) the current applications of F-gases, (ii) the environmental issues caused by F-gases, (iii) current methods of destruction of F-gases and (iv) recent work in the field towards the chemical repurposing of F-gases. There is a great opportunity to tackle the environmental and sustainability issues created by F-gases by developing reactions that repurpose these molecules.
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Affiliation(s)
- Daniel J Sheldon
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, Shepherds Bush, London, W12 0BZ, UK.
| | - Mark R Crimmin
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, Shepherds Bush, London, W12 0BZ, UK.
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8
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Balaraman K, Wolf C. Chemodivergent Csp 3─F bond functionalization and cross-electrophile alkyl-alkyl coupling with alkyl fluorides. SCIENCE ADVANCES 2022; 8:eabn7819. [PMID: 35622926 PMCID: PMC9140971 DOI: 10.1126/sciadv.abn7819] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The widespread use of fluorinated organic compounds in the health, agrochemical, and materials sciences is sustained by a steadily growing pool of commercially available fine chemicals. The synthetic utility of the increasingly ubiquitous Csp3─F bond, however, remains to be fully exploited, which is often a difficult task because of its paramount stability and chemical inertness. Here, we demonstrate chemodivergent activation of monofluoroalkyl compounds toward either nucleophilic or electrophilic intermediates. This is accomplished under conditions that are compatible with several reaction types and many functional groups, which drastically widens the current scope of organofluorine chemistry and sets the stage for carbon-carbon and carbon-heteroatom bond formations, stereoselective construction of bisoxindole alkaloid scaffolds via in situ Umpolung, and cross-electrophilic coupling methodology. The selective generation of either nucleophilic or electrophilic species and the possibility of doing so simultaneously or, alternatively, switching molecular polarity enable previously unidentified synthetic opportunities that recognize alkyl fluorides as chemodivergent building blocks.
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9
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Pietrasiak E, Lee E. Grignard reagent formation via C-F bond activation: a centenary perspective. Chem Commun (Camb) 2022; 58:2799-2813. [PMID: 35044387 DOI: 10.1039/d1cc06753b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Examples of Grignard reagents obtained by C-F bond activation with magnesium have kept appearing in the literature over the last century. Due to the high bond dissociation energy of the C-F bond, a lot of effort has been invested in the preparation of highly active forms of magnesium for this purpose. Originally, magnesium activation was achieved by the application of additives, notably iodine. Later work focused on the generation of highly active magnesium powder by reduction of magnesium salts with alkali metals ("Rieke magnesium"). Modern approaches to the problem involve the application of Mg(I)-Mg(I) dimers and C-F bond activation performed by a transition metal catalyst followed by transmetallation with a magnesium salt. The purpose of this article is to provide an overview of fluoro-Grignard reagent preparation approaches reported to date.
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Affiliation(s)
- Ewa Pietrasiak
- Department of Chemistry, Pohang University of Science and Technology, Pohang, 37673, South Korea.
| | - Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology, Pohang, 37673, South Korea. .,Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang 37673, South Korea
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10
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Rösch B, Harder S. New horizons in low oxidation state group 2 metal chemistry. Chem Commun (Camb) 2021; 57:9354-9365. [PMID: 34528959 DOI: 10.1039/d1cc04147a] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Since the seminal report on Mg in the +I oxidation state in 2007, low-valent complexes featuring a MgI-MgI bond developed from trophy molecules to state-of-the-art reducing agents. Despite increasing interest in low-valency of the other group 2 metals, this area was restricted for a long time to a rare example of a CaI(arene)CaI inverse sandwich. This feature article focuses on the most recent developments in the field, highlighting recent breakthroughs for Be, Mg and Ca. The more exotic metal Be was the first to be isolated as a zero-valent complex which could be oxidized to a BeI species. There also has been interest in breaking the MgI-MgI bond with superbulky β-diketiminate ligands (BDI) that suppress (BDI)Mg-Mg(BDI) bond formation. This led to Mg-Mg bond elongation or Mg-N bond cleavage. Several reports on attempts to isolate (BDI)Mg˙ radicals by combinations of ligand bulk, addition of neutral ligands or UV(vis) irradiation led to reduction of the aromatic solvents, underscoring the high reactivity of these open shell species. Only recently, zero-valent complexes of Mg were introduced. Double reduction of a (BDI)MgI complex with Na gave [(BDI)Mg-]Na+. This Mg0 complex crystallized as a dimer in which the Na+ cations bridge the two (BDI)Mg- anions which react as Mg nucleophiles. Thermal decomposition led to spontaneous formation of Na0 and a trinuclear (BDI)MgMgMg(BDI) complex. This mixed-valence Mg3-complex is a prime example of the fleeting multinuclear Mgn intermediates discussed on the way from Mg metal to Grignard reagent. Attempts to prepare low-valent CaI compounds by reduction of (BDI)CaI led to dearomatization of the arene solvents: (BDI)Ca(arene)Ca(BDI). Reduction in alkanes prevented this decomposition pathway but led to N2 reduction and isolation of (BDI)Ca(N2)Ca(BDI), representing the first example of molecular nitrogen fixation with an early main group metal. As the N22- anion reacts in most cases as a very strong two-electron reductant, LCa(N2)CaL could be seen as a synthon for hitherto elusive CaI-CaI complexes. Theoretical calculations suggest that participation of Ca d-orbitals is relevant for N2 activation. These most recent developments in low-valent group 2 metal chemistry will revive this area and undoubtly lead to new reactivities and applications.
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Affiliation(s)
- Bastian Rösch
- Inorganic and Organometallic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany.
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry, Universität Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany.
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11
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Wiesinger M, Rösch B, Knüpfer C, Mai J, Langer J, Harder S. Carbon‐Halogen Bond Activation with Powerful Heavy Alkaline Earth Metal Hydrides. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100529] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Michael Wiesinger
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Bastian Rösch
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Christian Knüpfer
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Jonathan Mai
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Jens Langer
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Sjoerd Harder
- Inorganic and Organometallic Chemistry Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
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12
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Sheldon DJ, Crimmin MR. Complete deconstruction of SF 6 by an aluminium(I) compound. Chem Commun (Camb) 2021; 57:7096-7099. [PMID: 34159971 PMCID: PMC8291285 DOI: 10.1039/d1cc02838c] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The room-temperature activation of SF6, a potent greenhouse gas, is reported using a monovalent aluminium(i) reagent to form well-defined aluminium(iii) fluoride and aluminium(iii) sulfide products. New reactions have been developed to utilise the aluminium(iii) fluoride and aluminium(iii) sulfide as a nucleophilic source of F− and S2− for a range of electrophiles. The overall reaction sequence results in the net transfer of fluorine or sulfur atoms from an environmentally detrimental gas to useful organic products. The room-temperature activation of SF6, a potent greenhouse gas, is reported using a monovalent aluminium(i) reagent to form well-defined aluminium(iii) fluoride and aluminium(iii) sulfide products.![]()
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Affiliation(s)
- Daniel J Sheldon
- Molecular Sciences Research Hub, Department of Chemistry, Imperial College London, London, W12 0BZ, UK.
| | - Mark R Crimmin
- Molecular Sciences Research Hub, Department of Chemistry, Imperial College London, London, W12 0BZ, UK.
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13
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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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14
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Willcox DR, Nichol GS, Thomas SP. Borane-Catalyzed C(sp3)–F Bond Arylation and Esterification Enabled by Transborylation. ACS Catal 2021. [DOI: 10.1021/acscatal.1c00282] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Dominic R. Willcox
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh, EH9 3FJ, U.K
| | - Gary S. Nichol
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh, EH9 3FJ, U.K
| | - Stephen P. Thomas
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh, EH9 3FJ, U.K
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15
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Kysliak O, Görls H, Kretschmer R. Cooperative Bond Activation by a Bimetallic Main-Group Complex. J Am Chem Soc 2021; 143:142-148. [PMID: 33356229 DOI: 10.1021/jacs.0c12166] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Inspired by natural metalloenzymes that efficiently catalyze a variety of transformations, chemists have developed large numbers of dinuclear transition-metal complexes with extraordinary properties and reactivity patterns. For main-group element compounds, however, metal-metal cooperativity is much less explored. Here we present the synthesis and characterization of a room-temperature-stable compound with two separated two-coordinated gallium(I) centers possessing both a lone pair of electrons and a vacant orbital, reminiscent of singlet carbenes. This species displays enhanced reactivity compared to its mononuclear counterpart due to bimetallic cooperativity that allows for the facile activation of strong C-F bonds across the gallium-gallium bond. Two mechanistic scenarios of the cooperative bond activation have been identified by DFT and DLPNO-CCSD(T) calculations.
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Affiliation(s)
- Oleksandr Kysliak
- Institute of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743 Jena, Germany
| | - Helmar Görls
- Institute of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743 Jena, Germany
| | - Robert Kretschmer
- Institute of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743 Jena, Germany.,Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743 Jena, Germany
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16
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Sheldon DJ, Coates G, Crimmin MR. Defluorosilylation of trifluoromethane: upgrading an environmentally damaging fluorocarbon. Chem Commun (Camb) 2020; 56:12929-12932. [PMID: 32975261 DOI: 10.1039/d0cc04592f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The rapid, room-temperature defluorosilylation of trifluoromethane, a highly potent greenhouse gas, has been achieved using a simple silyl lithium reagent. An extensive computational mechanistic analysis provides a viable reaction pathway and demonstrates the unexpected electrophilic nature of LiCF3. The reaction generates a bench stable fluorinated building block that shows promise as an easy-to-use difluoromethylating agent. The difluoromethyl group is an increasingly important bioisostere in active pharmaceutical ingredients, and therefore our methodology creates value from waste. The potential scalability of the process has been demonstrated by achieving the reaction on a gram-scale.
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Affiliation(s)
- Daniel J Sheldon
- Molecular Sciences Research Hub, Department of Chemistry, Imperial College London, London W12 0BZ, UK.
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17
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Maekawa Y, Nambo M, Yokogawa D, Crudden CM. Alkyltriflones in the Ramberg-Bäcklund Reaction: An Efficient and Modular Synthesis of gem-Difluoroalkenes. J Am Chem Soc 2020; 142:15667-15672. [PMID: 32799441 DOI: 10.1021/jacs.0c07924] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The unprecedented synthesis of gem-difluoroalkenes through the Ramberg-Bäcklund reaction of alkyl triflones is described herein. Structurally diverse, fully substituted gem-difluoroalkenes that are difficult to prepare by other methods can be easily prepared from readily available triflones by treatment with specific Grignard reagents. Experimental and computational studies provide insight into the unique and critical role of the Grignard reagent, which serves both as a base to remove the α-proton and as a Lewis acid to assist C-F bond activation.
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Affiliation(s)
- Yuuki Maekawa
- Department of Chemistry, Queen's University, Chernoff Hall, Kingston, Ontario, Canada.,Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya, Japan
| | - Masakazu Nambo
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya, Japan
| | - Daisuke Yokogawa
- Graduate School of Arts and Science, The University of Tokyo, Komaba, Meguro-ku, Tokyo, Japan
| | - Cathleen M Crudden
- Department of Chemistry, Queen's University, Chernoff Hall, Kingston, Ontario, Canada.,Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya, Japan
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18
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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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19
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Kysliak O, Görls H, Kretschmer R. C–F bond activation by pentamethylcyclopentadienyl-aluminium(i): a combined experimental/computational exercise. Chem Commun (Camb) 2020; 56:7865-7868. [DOI: 10.1039/d0cc00003e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Although (AlCp*)4 is one of the longest known stable aluminium(i) compounds, it still has surprising reactivities in store as illustrated by the ability to break strong C–F bonds.
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Affiliation(s)
- Oleksandr Kysliak
- Institute of Inorganic and Analytical Chemistry (IAAC)
- Friedrich Schiller University Jena
- 07743 Jena
- Germany
| | - Helmar Görls
- Institute of Inorganic and Analytical Chemistry (IAAC)
- Friedrich Schiller University Jena
- 07743 Jena
- Germany
| | - Robert Kretschmer
- Institute of Inorganic and Analytical Chemistry (IAAC)
- Friedrich Schiller University Jena
- 07743 Jena
- Germany
- Jena Center for Soft Matter (JCSM)
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20
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Coates G, Tan HY, Kalff C, White AJP, Crimmin MR. Defluorosilylation of Industrially Relevant Fluoroolefins Using Nucleophilic Silicon Reagents. Angew Chem Int Ed Engl 2019; 58:12514-12518. [DOI: 10.1002/anie.201906825] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Greg Coates
- Molecular Sciences Research HubImperial College London 80 Wood Lane, Shepherds Bush London W12 0BZ UK
| | - Hui Yee Tan
- Molecular Sciences Research HubImperial College London 80 Wood Lane, Shepherds Bush London W12 0BZ UK
| | - Carolin Kalff
- Molecular Sciences Research HubImperial College London 80 Wood Lane, Shepherds Bush London W12 0BZ UK
| | - Andrew J. P. White
- Molecular Sciences Research HubImperial College London 80 Wood Lane, Shepherds Bush London W12 0BZ UK
| | - Mark R. Crimmin
- Molecular Sciences Research HubImperial College London 80 Wood Lane, Shepherds Bush London W12 0BZ UK
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21
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Coates G, Tan HY, Kalff C, White AJP, Crimmin MR. Defluorosilylation of Industrially Relevant Fluoroolefins Using Nucleophilic Silicon Reagents. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201906825] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Greg Coates
- Molecular Sciences Research HubImperial College London 80 Wood Lane, Shepherds Bush London W12 0BZ UK
| | - Hui Yee Tan
- Molecular Sciences Research HubImperial College London 80 Wood Lane, Shepherds Bush London W12 0BZ UK
| | - Carolin Kalff
- Molecular Sciences Research HubImperial College London 80 Wood Lane, Shepherds Bush London W12 0BZ UK
| | - Andrew J. P. White
- Molecular Sciences Research HubImperial College London 80 Wood Lane, Shepherds Bush London W12 0BZ UK
| | - Mark R. Crimmin
- Molecular Sciences Research HubImperial College London 80 Wood Lane, Shepherds Bush London W12 0BZ UK
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22
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Ma M, Wang H, Wang J, Shen L, Zhao Y, Xu WH, Wu B, Yang XJ. Mg–Mg-bonded compounds with N,N′-dipp-substituted phenanthrene-diamido and o-phenylene-diamino ligands. Dalton Trans 2019; 48:2295-2299. [DOI: 10.1039/c9dt00028c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two Mg–Mg-bonded compounds were synthesized by using phenanthrene-diimine and o-phenylenediamine ligands; their UV-Vis and fluorescence spectra and reactivity were studied.
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Affiliation(s)
- Meimei Ma
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710069
- China
| | - Huanhuan Wang
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710069
- China
| | - Juju Wang
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710069
- China
| | - Lingyi Shen
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710069
- China
| | - Yanxia Zhao
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710069
- China
| | - Wen-Hua Xu
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710069
- China
| | - Biao Wu
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710069
- China
| | - Xiao-Juan Yang
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education
- College of Chemistry and Materials Science
- Northwest University
- Xi'an 710069
- China
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23
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Bole LJ, Davin L, Kennedy AR, McLellan R, Hevia E. Magnesium-mediated arylation of amines via C–F bond activation of fluoroarenes. Chem Commun (Camb) 2019; 55:4339-4342. [DOI: 10.1039/c9cc01670h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Exploiting the high nucleophilic power of structurally defined β-diketiminate stabilised magnesium amides, a new method for amine arylation via rapid C–F bond activation of fluoroarenes is introduced.
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Affiliation(s)
- Leonie J. Bole
- WestCHEM
- Department of Pure and Applied Chemistry University of Strathclyde Glasgow
- UK
| | - Laia Davin
- WestCHEM
- Department of Pure and Applied Chemistry University of Strathclyde Glasgow
- UK
| | - Alan R. Kennedy
- WestCHEM
- Department of Pure and Applied Chemistry University of Strathclyde Glasgow
- UK
| | - Ross McLellan
- WestCHEM
- Department of Pure and Applied Chemistry University of Strathclyde Glasgow
- UK
| | - Eva Hevia
- WestCHEM
- Department of Pure and Applied Chemistry University of Strathclyde Glasgow
- UK
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24
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Deacy AC, Durr CB, Garden JA, White AJP, Williams CK. Groups 1, 2 and Zn(II) Heterodinuclear Catalysts for Epoxide/CO2 Ring-Opening Copolymerization. Inorg Chem 2018; 57:15575-15583. [DOI: 10.1021/acs.inorgchem.8b02923] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Arron C. Deacy
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Christopher B. Durr
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Jennifer A. Garden
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Andrew J. P. White
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom
| | - Charlotte K. Williams
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
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25
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Coates G, Ward BJ, Bakewell C, White AJP, Crimmin MR. Reactions of Fluoroalkanes with Mg-Mg Bonds: Scope, sp 3 C-F/sp 2 C-F Coupling and Mechanism. Chemistry 2018; 24:16282-16286. [PMID: 30207410 PMCID: PMC6471154 DOI: 10.1002/chem.201804580] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Indexed: 01/19/2023]
Abstract
sp3C−F Bonds of fluoroalkanes (7 examples; 1°, 2° and 3°) undergo addition to a low‐valent Mg−Mg species generating reactive organomagnesium reagents. Further reactions with a series of electrophiles results in a net C−F to C−B, C−Si, C−Sn or C−C bond transformation (11 examples, diversity). The new reactivity has been exploited in an unprecedented one‐pot magnesium‐mediated coupling of sp3C−F and sp2C−F bonds. Calculations suggest that the sp3C−F bond activation step occurs by frontside nucleophilic attack of the Mg−Mg reagent on the fluoroalkane.
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Affiliation(s)
- Greg Coates
- Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - Bryan J Ward
- Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - Clare Bakewell
- Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - Andrew J P White
- Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - Mark R Crimmin
- Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, UK
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