1
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Yang WP, Miao HJ, Liu L, Duan XH, Guo LN. Visible Light-Promoted Aromatization-Driven Deconstructive Fluorination of Spiro Carbocycles. Org Lett 2024; 26:7442-7446. [PMID: 39186378 DOI: 10.1021/acs.orglett.4c02793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/28/2024]
Abstract
A visible light-promoted aromatization-driven deconstructive fluorination of spiro carbocycles is presented. A series of spiro dihydroquinazolinones reacted efficiently with NFSI under visible light irradiation to afford the 2-(4-fluoroalkyl)quinazolin-4(3H)-ones in good yields with excellent functional group tolerance. A radical pathway involving C-C bond cleavage and F atom transfer is proposed for the reaction. In addition, the ring-opening chlorination of spiro dihydroquinazolinones with NCS was also applicable.
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Affiliation(s)
- Wen-Peng Yang
- Department of Chemistry, School of Chemistry, Xi'an Key Laboratory of Sustainable Energy Material Chemistry and Engineering Research Center of Energy Storage, Materials and Devices, Ministry of Education, Xi'an Jiaotong University, Xi'an 710049, China
| | - Hong-Jie Miao
- Department of Chemistry, School of Chemistry, Xi'an Key Laboratory of Sustainable Energy Material Chemistry and Engineering Research Center of Energy Storage, Materials and Devices, Ministry of Education, Xi'an Jiaotong University, Xi'an 710049, China
| | - Le Liu
- Department of Chemistry, School of Chemistry, Xi'an Key Laboratory of Sustainable Energy Material Chemistry and Engineering Research Center of Energy Storage, Materials and Devices, Ministry of Education, Xi'an Jiaotong University, Xi'an 710049, China
| | - Xin-Hua Duan
- Department of Chemistry, School of Chemistry, Xi'an Key Laboratory of Sustainable Energy Material Chemistry and Engineering Research Center of Energy Storage, Materials and Devices, Ministry of Education, Xi'an Jiaotong University, Xi'an 710049, China
- State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, China
| | - Li-Na Guo
- Department of Chemistry, School of Chemistry, Xi'an Key Laboratory of Sustainable Energy Material Chemistry and Engineering Research Center of Energy Storage, Materials and Devices, Ministry of Education, Xi'an Jiaotong University, Xi'an 710049, China
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2
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Lai J, Xiao X, Shao S, Wang S, Kan J, Su W. Photoinduced Transition-Metal and External Photosensitizer Free Benzylic Fluorination of Unactivated Alkylarenes. Chemistry 2024; 30:e202401669. [PMID: 38970448 DOI: 10.1002/chem.202401669] [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: 04/28/2024] [Revised: 06/20/2024] [Accepted: 07/05/2024] [Indexed: 07/08/2024]
Abstract
A green and efficient protocol for the direct monofluorination of unactivated alkylarenes under visible-light irradiation has been developed, without any extraneous transition-metal catalysts or photosensitizers. This method is compatible with a broad spectrum of functional groups, including carboxylic and alcoholic scaffolds, under mild reaction conditions. Gram-scale synthesis of a fluorine-containing pharmaceutical analogue was successfully executed, underscoring the strategy's reliability and practicality. Furthermore, mechanistic studies suggest that a single-electron transfer mechanism might be responsible for the generation of the benzylic radicals in initiation step.
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Affiliation(s)
- Jiawen Lai
- College of Chemistry & Materials Science, Fujian Normal University, 350007, Fuzhou Fujian, P. R. China
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002, Fuzhou Fujian, P. R. China
| | - Xuan Xiao
- College of Chemistry & Materials Science, Fujian Normal University, 350007, Fuzhou Fujian, P. R. China
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002, Fuzhou Fujian, P. R. China
| | - Shixing Shao
- College of Chemistry & Materials Science, Fujian Normal University, 350007, Fuzhou Fujian, P. R. China
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002, Fuzhou Fujian, P. R. China
| | - Shuping Wang
- College of Chemistry & Materials Science, Fujian Normal University, 350007, Fuzhou Fujian, P. R. China
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002, Fuzhou Fujian, P. R. China
| | - Jian Kan
- College of Chemistry & Materials Science, Fujian Normal University, 350007, Fuzhou Fujian, P. R. China
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002, Fuzhou Fujian, P. R. China
| | - Weiping Su
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002, Fuzhou Fujian, P. R. China
- Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, 350108, Fuzhou Fujian, P. R. China
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3
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Novaes LFT, Ho JSK, Mao K, Villemure E, Terrett JA, Lin S. α,β-Desaturation and Formal β-C(sp 3)-H Fluorination of N-Substituted Amines: A Late-Stage Functionalization Strategy Enabled by Electrochemistry. J Am Chem Soc 2024; 146:22982-22992. [PMID: 39132893 PMCID: PMC11366977 DOI: 10.1021/jacs.4c02548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
Incorporation of C(sp3)-F bonds in biologically active compounds is a common strategy employed in medicinal and agricultural chemistry to tune pharmacokinetic and pharmacodynamic properties. Due to the limited number of robust strategies for C(sp3)-H fluorination of complex molecules, time-consuming de novo syntheses of such fluorinated analogs are typically required, representing a major bottleneck in the drug discovery process. In this work, we present a general and operationally simple strategy for site-specific β-C(sp3)-H fluorination of amine derivatives including carbamates, amides, and sulfonamides, which is compatible with a wide range of functional groups including N-heteroarenes. In this approach, an improved electrochemical Shono oxidation is used to set the site of functionalization via net α,β-desaturation to access enamine derivatives. We further developed a series of new transformations of these enamine intermediates to synthesize a variety of β-fluoro-α-functionalized structures, allowing efficient access to pertinent targets to accelerate drug discovery campaigns.
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Affiliation(s)
- Luiz F T Novaes
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Justin S K Ho
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Kaining Mao
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Elisia Villemure
- Department of Discovery Chemistry, Genentech, Inc., South San Francisco, California 94080, United States
| | - Jack A Terrett
- Department of Discovery Chemistry, Genentech, Inc., South San Francisco, California 94080, United States
| | - Song Lin
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
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4
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Atkins AP, Dean AC, Lennox AJJ. Benzylic C(sp 3)-H fluorination. Beilstein J Org Chem 2024; 20:1527-1547. [PMID: 39015617 PMCID: PMC11250007 DOI: 10.3762/bjoc.20.137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 06/26/2024] [Indexed: 07/18/2024] Open
Abstract
The selective fluorination of C(sp3)-H bonds is an attractive target, particularly for pharmaceutical and agrochemical applications. Consequently, over recent years much attention has been focused on C(sp3)-H fluorination, and several methods that are selective for benzylic C-H bonds have been reported. These protocols operate via several distinct mechanistic pathways and involve a variety of fluorine sources with distinct reactivity profiles. This review aims to give context to these transformations and strategies, highlighting the different tactics to achieve fluorination of benzylic C-H bonds.
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Affiliation(s)
| | - Alice C Dean
- University of Bristol, School of Chemistry, Bristol, BS8 1TS, U.K.
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5
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Joven-Sancho D, Echeverri A, Saffon-Merceron N, Contreras-García J, Nebra N. An Organocopper(III) Fluoride Triggering C-CF 3 Bond Formation. Angew Chem Int Ed Engl 2024; 63:e202319412. [PMID: 38147576 DOI: 10.1002/anie.202319412] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 12/22/2023] [Accepted: 12/22/2023] [Indexed: 12/28/2023]
Abstract
Copper(III) fluorides are catalytically competent, yet elusive, intermediates in cross-coupling. The synthesis of [PPh4 ][CuIII (CF3 )3 F] (2), the first stable (isolable) CuIII -F, was accomplished via chloride addition to [CuIII (CF3 )3 (py)] (1) yielding [PPh4 ][CuIII (CF3 )3 Cl(py)] (1⋅Cl), followed by treatment with AgF. The CuIII halides 1⋅Cl and 2 were fully characterized using nuclear magnetic resonance (NMR) spectroscopy, single crystal X-ray diffraction (Sc-XRD) and elemental analysis (EA). Complex 2 proved capable of forging C-CF3 bonds from silyl-capped alkynes. In-depth mechanistic studies combining probes, theoretical calculations, trapping of intermediate 4a ([PPh4 ][CuIII (CF3 )3 (C≡CPh)]) and radical tests unveil the key role of the CuIII acetylides that undergo facile 2e- reductive elimination furnishing the trifluoromethylated alkynes (RC≡CCF3 ), which are industrially relevant synthons in drug discovery, pharma and agrochemistry.
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Affiliation(s)
- Daniel Joven-Sancho
- Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA), Université Paul Sabatier, CNRS, 118 Route de Narbonne, 31062, Toulouse, France
| | - Andrea Echeverri
- Laboratoire de Chimie Théorique (LCT), Sorbonne Université, CNRS, 4, Place Jussieu, 75005, Paris, France
| | - Nathalie Saffon-Merceron
- Institut de Chimie de Toulouse ICT-UAR2599, Université Paul Sabatier, CNRS, 31062, Toulouse Cedex, France
| | - Julia Contreras-García
- Laboratoire de Chimie Théorique (LCT), Sorbonne Université, CNRS, 4, Place Jussieu, 75005, Paris, France
| | - Noel Nebra
- Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA), Université Paul Sabatier, CNRS, 118 Route de Narbonne, 31062, Toulouse, France
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6
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Yuan Z, Britton R. Development and application of decatungstate catalyzed C-H 18F- and 19F-fluorination, fluoroalkylation and beyond. Chem Sci 2023; 14:12883-12897. [PMID: 38023504 PMCID: PMC10664588 DOI: 10.1039/d3sc04027e] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/11/2023] [Indexed: 12/01/2023] Open
Abstract
Over the past few decades, photocatalytic C-H functionalization reactions have received increasing attention due to the often mild reaction conditions and complementary selectivities to conventional functionalization processes. Now, photocatalytic C-H functionalization is a widely employed tool, supporting activities ranging from complex molecule synthesis to late-stage structure-activity relationship studies. In this perspective, we will discuss our efforts in developing a photocatalytic decatungstate catalyzed C-H fluorination reaction as well as its practical application realized through collaborations with industry partners at Hoffmann-La Roche and Merck, and extension to radiofluorination with radiopharmaceutical chemists and imaging experts at TRIUMF and the BC Cancer Agency. Importantly, we feel that our efforts address a question of utility posed by Professor Tobias Ritter in "Late-Stage Fluorination: Fancy Novelty or Useful Tool?" (ACIE, 2015, 54, 3216). In addition, we will discuss decatungstate catalyzed C-H fluoroalkylation and the interesting electrostatic effects observed in decatungstate-catalyzed C-H functionalization. We hope this perspective will inspire other researchers to explore the use of decatungstate for the purposes of photocatalytic C-H functionalization and further advance the exploitation of electrostatic effects for both rate acceleration and directing effects in these reactions.
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Affiliation(s)
- Zheliang Yuan
- Department of Chemistry, Simon Fraser University Burnaby British Columbia V5A 1S2 Canada
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University Jinhua Zhejiang 321004 China
| | - Robert Britton
- Department of Chemistry, Simon Fraser University Burnaby British Columbia V5A 1S2 Canada
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7
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Wang M, Rowshanpour R, Guan L, Ruskin J, Nguyen PM, Wang Y, Zhang QA, Liu R, Ling B, Woltornist R, Stephens AM, Prasad A, Dudding T, Lectka T, Pitts CR. Competition between C-C and C-H Bond Fluorination: A Continuum of Electron Transfer and Hydrogen Atom Transfer Mechanisms. J Am Chem Soc 2023; 145:22442-22455. [PMID: 37791901 DOI: 10.1021/jacs.3c06477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
In 2015, we reported a photochemical method for directed C-C bond cleavage/radical fluorination of relatively unstrained cyclic acetals using Selectfluor and catalytic 9-fluorenone. Herein, we provide a detailed mechanistic study of this reaction, during which it was discovered that the key electron transfer step proceeds through substrate oxidation from a Selectfluor-derived N-centered radical intermediate (rather than through initially suspected photoinduced electron transfer). This finding led to proof of concept for two new methodologies, demonstrating that unstrained C-C bond fluorination can also be achieved under chemical and electrochemical conditions. Moreover, as C-C and C-H bond fluorination reactions are both theoretically possible on 2-aryl-cycloalkanone acetals and would involve the same reactive intermediate, we studied the competition between single-electron transfer (SET) and apparent hydrogen-atom transfer (HAT) pathways in acetal fluorination reactions using density functional theory. Finally, these analyses were applied more broadly to other classes of C-H and C-C bond fluorination reactions developed over the past decade, addressing the feasibility of SET processes masquerading as HAT in C-H fluorination literature.
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Affiliation(s)
- Muyuan Wang
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Rozhin Rowshanpour
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way St. Catharines, Ontario L2S 3A1, Canada
| | - Liangyu Guan
- BayRay Innovation Center, Shenzhen Bay Laboratory, Shenzhen 51832, China
| | - Jonah Ruskin
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Phuong Minh Nguyen
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Yuang Wang
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Qinze Arthur Zhang
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Ran Liu
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Bill Ling
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Ryan Woltornist
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Alexander M Stephens
- Department of Chemistry, University of California Davis, 1 Shields Avenue, Davis, California 95616, United States
| | - Aarush Prasad
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Travis Dudding
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way St. Catharines, Ontario L2S 3A1, Canada
| | - Thomas Lectka
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Cody Ross Pitts
- Department of Chemistry, University of California Davis, 1 Shields Avenue, Davis, California 95616, United States
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8
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Romero AH. C-H Bond Functionalization of N-Heteroarenes Mediated by Selectfluor. Top Curr Chem (Cham) 2023; 381:29. [PMID: 37736818 DOI: 10.1007/s41061-023-00437-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 08/21/2023] [Indexed: 09/23/2023]
Abstract
Herein, recent developments for Selectfluor-mediated C-H functionalization of N-heteroarenes are described. This type of C-H bond activation is an attractive and competitive alternative to traditional methodologies, allowing the functionalization of a variety of chemical functions. In addition, Selectfluor is a more sustainable and economically accessible oxidant compared with expensive/toxic metals or hazardous peroxides. For a practical understanding, the current review classified systematically the reported strategies in four subsections as follows: (1) carbon-carbon formation, (2) carbon-nitrogen bond formation, (3) carbon-chalcogen bond, and (4) carbon-halogen bond formation. Mechanistic aspects and reaction conditions are fully discussed to provide an understanding of the aspects that govern C-H functionalization in N-heteroarenes mediated by Selectfluor.
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Affiliation(s)
- Angel H Romero
- Grupo de Química Orgánica Medicinal, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Igua 4225, 11400, Montevideo, Uruguay.
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9
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Panda C, Anny-Nzekwue O, Doyle LM, Gericke R, McDonald AR. Evidence for a High-Valent Iron-Fluoride That Mediates Oxidative C(sp 3)-H Fluorination. JACS AU 2023; 3:919-928. [PMID: 37006763 PMCID: PMC10052241 DOI: 10.1021/jacsau.3c00021] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/14/2023] [Accepted: 02/15/2023] [Indexed: 06/19/2023]
Abstract
[FeII(NCCH3)(NTB)](OTf)2 (NTB = tris(2-benzimidazoylmethyl)amine, OTf = trifluoromethanesulfonate) was reacted with difluoro(phenyl)-λ3-iodane (PhIF2) in the presence of a variety of saturated hydrocarbons, resulting in the oxidative fluorination of the hydrocarbons in moderate-to-good yields. Kinetic and product analysis point towards a hydrogen atom transfer oxidation prior to fluorine radical rebound to form the fluorinated product. The combined evidence supports the formation of a formally FeIV(F)2 oxidant that performs hydrogen atom transfer followed by the formation of a dimeric μ-F-(FeIII)2 product that is a plausible fluorine atom transfer rebound reagent. This approach mimics the heme paradigm for hydrocarbon hydroxylation, opening up avenues for oxidative hydrocarbon halogenation.
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10
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Li Y, Dong Y, Wang X, Li G, Xue H, Xin W, Zhang Q, Guan W, Fu J. Regio-, Site-, and Stereoselective Three-Component Aminofluorination of 1,3-Dienes via Cooperative Silver Salt and Copper Catalysis. ACS Catal 2023. [DOI: 10.1021/acscatal.2c06025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Yang Li
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis and Institute of Functional Material Chemistry, Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Yujiao Dong
- Institute of Functional Material Chemistry, Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Xin Wang
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis and Institute of Functional Material Chemistry, Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Guangfu Li
- Institute of Functional Material Chemistry, Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Huiqing Xue
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis and Institute of Functional Material Chemistry, Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Wanyang Xin
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis and Institute of Functional Material Chemistry, Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Qian Zhang
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis and Institute of Functional Material Chemistry, Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Wei Guan
- Institute of Functional Material Chemistry, Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Junkai Fu
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis and Institute of Functional Material Chemistry, Department of Chemistry, Northeast Normal University, Changchun 130024, China
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11
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Hintz H, Bower J, Tang J, LaLama M, Sevov C, Zhang S. Copper-Catalyzed Electrochemical C-H Fluorination. CHEM CATALYSIS 2023; 3:100491. [PMID: 36743279 PMCID: PMC9894310 DOI: 10.1016/j.checat.2022.100491] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We report the systematic development of an electrooxidative methodology that translates stoichiometric C-H fluorination reactivity of an isolable CuIII fluoride complex into a catalytic process. The critical challenges of electrocatalysis with a highly reactive CuIII species were addressed by the judicious selection of electrolyte, F- source, and sacrificial electron acceptor. Catalyst-controlled C-H fluorination occurs with a preference for hydridic C-H bonds with high bond dissociation energies over weaker but less hydridic C-H bonds. The selectivity is driven by an oxidative asynchronous proton-coupled elelctron transfer (PCET) at an electrophilic CuIII-F complex. We further demonstrate that the asynchronicity factor of hydrogen atom transfer η can be used as a guideline to rationalize the selectivity of C-H fluorination.
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Affiliation(s)
- Heather Hintz
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Jamey Bower
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Jinghua Tang
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Matthew LaLama
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Christo Sevov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Shiyu Zhang
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
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12
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Yakubov S, Stockerl WJ, Tian X, Shahin A, Mandigma MJP, Gschwind RM, Barham JP. Benzoates as photosensitization catalysts and auxiliaries in efficient, practical, light-powered direct C(sp 3)-H fluorinations. Chem Sci 2022; 13:14041-14051. [PMID: 36540818 PMCID: PMC9728569 DOI: 10.1039/d2sc05735b] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 10/28/2022] [Indexed: 12/14/2023] Open
Abstract
Of the methods for direct fluorination of unactivated C(sp3)-H bonds, photosensitization of SelectFluor is a promising approach. Although many substrates can be activated with photosensitizing catalysts, issues remain that hamper fluorination of complex molecules. Alcohol- or amine-containing functional groups are not tolerated, fluorination regioselectivity follows factors endogenous to the substrate and cannot be influenced by the catalyst, and reactions are highly air-sensitive. We report that benzoyl groups serve as highly efficient photosensitizers which, in combination with SelectFluor, enable visible light-powered direct fluorination of unactivated C(sp3)-H bonds. Compared to previous photosensitizer architectures, the benzoyls have versatility to function both (i) as a photosensitizing catalyst for simple substrate fluorinations and (ii) as photosensitizing auxiliaries for complex molecule fluorinations that are easily installed and removed without compromising yield. Our auxiliary approach (i) substantially decreases the reaction's induction period, (ii) enables C(sp3)-H fluorination of many substrates that fail under catalytic conditions, (iii) increases kinetic reproducibility, and (iv) promotes reactions to higher yields, in shorter times, on multigram scales, and even under air. Observations and mechanistic studies suggest an intimate 'assembly' of auxiliary and SelectFluor prior/after photoexcitation. The auxiliary allows other EnT photochemistry under air. Examples show how auxiliary placement proximally directs regioselectivity, where previous methods are substrate-directed.
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Affiliation(s)
- Shahboz Yakubov
- Fakultät für Chemie und Pharmazie, Universität Regensburg 93040 Regensburg Germany
| | - Willibald J Stockerl
- Fakultät für Chemie und Pharmazie, Universität Regensburg 93040 Regensburg Germany
| | - Xianhai Tian
- Fakultät für Chemie und Pharmazie, Universität Regensburg 93040 Regensburg Germany
| | - Ahmed Shahin
- Fakultät für Chemie und Pharmazie, Universität Regensburg 93040 Regensburg Germany
- Chemistry Department, Faculty of Science, Benha University 13518 Benha Egypt
| | - Mark John P Mandigma
- Fakultät für Chemie und Pharmazie, Universität Regensburg 93040 Regensburg Germany
| | - Ruth M Gschwind
- Fakultät für Chemie und Pharmazie, Universität Regensburg 93040 Regensburg Germany
| | - Joshua P Barham
- Fakultät für Chemie und Pharmazie, Universität Regensburg 93040 Regensburg Germany
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13
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Stangier M, Scheremetjew A, Ackermann L. Chemo- and Site-Selective Electro-Oxidative Alkane Fluorination by C(sp 3 )-H Cleavage. Chemistry 2022; 28:e202201654. [PMID: 35844078 PMCID: PMC9804291 DOI: 10.1002/chem.202201654] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Indexed: 01/05/2023]
Abstract
Electrochemical fluorinations of C(sp3 )-H bonds with a nucleophilic fluoride source have been accomplished in a chemo- and site-selective fashion, avoiding the use of electrophilic F+ sources and stoichiometric oxidants. The introduced metal-free strategy exhibits high functional group tolerance, setting the stage for late-stage fluorinations of biorelevant motifs. The synthetic utility of the C(sp3 )-H fluorination was reflected by subsequent one-pot arylation of the generated benzylic fluorides.
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Affiliation(s)
- Maximilian Stangier
- Institut für Organische und Biomolekulare Chemie Wöhler Research Institute for Sustainable Chemistry (WISCh)Georg-August-Universität GöttingenTammannstrasse 237077GöttingenGermany
| | - Alexej Scheremetjew
- Institut für Organische und Biomolekulare Chemie Wöhler Research Institute for Sustainable Chemistry (WISCh)Georg-August-Universität GöttingenTammannstrasse 237077GöttingenGermany
| | - Lutz Ackermann
- Institut für Organische und Biomolekulare Chemie Wöhler Research Institute for Sustainable Chemistry (WISCh)Georg-August-Universität GöttingenTammannstrasse 237077GöttingenGermany
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14
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Harry SA, Xiang MR, Holt E, Zhu A, Ghorbani F, Patel D, Lectka T. Hydroxy-directed fluorination of remote unactivated C(sp 3)-H bonds: a new age of diastereoselective radical fluorination. Chem Sci 2022; 13:7007-7013. [PMID: 35774162 PMCID: PMC9200124 DOI: 10.1039/d2sc01907h] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 05/02/2022] [Indexed: 11/23/2022] Open
Abstract
We report a photochemically induced, hydroxy-directed fluorination that addresses the prevailing challenge of high diastereoselectivity in this burgeoning field. Numerous simple and complex motifs showcase a spectrum of regio- and stereochemical outcomes based on the configuration of the hydroxy group. Notable examples include a long-sought switch in the selectivity of the refractory sclareolide core, an override of benzylic fluorination, and a rare case of 3,3'-difluorination. Furthermore, calculations illuminate a low barrier transition state for fluorination, supporting our notion that alcohols are engaged in coordinated reagent direction. A hydrogen bonding interaction between the innate hydroxy directing group and fluorine is also highlighted for several substrates with 19F-1H HOESY experiments, calculations, and more.
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Affiliation(s)
- Stefan Andrew Harry
- Department of Chemistry, Johns Hopkins University 3400 N. Charles St. Baltimore MD 21218 USA
| | - Michael Richard Xiang
- Department of Chemistry, Johns Hopkins University 3400 N. Charles St. Baltimore MD 21218 USA
| | - Eric Holt
- Department of Chemistry, Johns Hopkins University 3400 N. Charles St. Baltimore MD 21218 USA
| | - Andrea Zhu
- Department of Chemistry, Johns Hopkins University 3400 N. Charles St. Baltimore MD 21218 USA
| | - Fereshte Ghorbani
- Department of Chemistry, Johns Hopkins University 3400 N. Charles St. Baltimore MD 21218 USA
| | - Dhaval Patel
- Department of Chemistry, Johns Hopkins University 3400 N. Charles St. Baltimore MD 21218 USA
| | - Thomas Lectka
- Department of Chemistry, Johns Hopkins University 3400 N. Charles St. Baltimore MD 21218 USA
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15
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Golden DL, Suh SE, Stahl SS. Radical C(sp3)-H functionalization and cross-coupling reactions. Nat Rev Chem 2022; 6:405-427. [PMID: 35965690 PMCID: PMC9364982 DOI: 10.1038/s41570-022-00388-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2022] [Indexed: 11/09/2022]
Abstract
C─H functionalization reactions are playing an increasing role in the preparation and modification of complex organic molecules, including pharmaceuticals, agrochemicals, and polymer precursors. Radical C─H functionalization reactions, initiated by hydrogen-atom transfer (HAT) and proceeding via open-shell radical intermediates, have been expanding rapidly in recent years. These methods introduce strategic opportunities to functionalize C(sp3)─H bonds. Examples include synthetically useful advances in radical-chain reactivity and biomimetic radical-rebound reactions. A growing number of reactions, however, proceed via "radical relay" whereby HAT generates a diffusible radical that is functionalized by a separate reagent or catalyst. The latter methods provide the basis for versatile C─H cross-coupling methods with diverse partners. In the present review, highlights of recent radical-chain and radical-rebound methods provide context for a survey of emerging radical-relay methods, which greatly expand the scope and utility of intermolecular C(sp3)─H functionalization and cross coupling.
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Affiliation(s)
- Dung L. Golden
- Department of Chemistry, University of Wisconsin–Madison, WI, USA
- These authors contributed equally: Dung L. Golden, Sung-Eun Suh
| | - Sung-Eun Suh
- Department of Chemistry, University of Wisconsin–Madison, WI, USA
- These authors contributed equally: Dung L. Golden, Sung-Eun Suh
- Department of Chemistry, Ajou University, Suwon, Republic of Korea
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin–Madison, WI, USA
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16
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Min S, Park B, Nedsaengtip J, Hyeok Hong S. Mechanochemical Direct Fluorination of Unactivated C(
sp
3
)−H Bonds. Adv Synth Catal 2022. [DOI: 10.1002/adsc.202200206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Sehye Min
- Department of Chemistry Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea
| | - Beomsoon Park
- Department of Chemistry Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea
| | - Jantakan Nedsaengtip
- Department of Chemistry Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea
| | - Soon Hyeok Hong
- Department of Chemistry Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea
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17
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Paik A, Paul S, Bhowmik S, Das R, Naveen T, Rana S. Recent Advances in First Row Transition Metal Mediated C‐H Halogenation of (Hetero)arenes and Alkanes. ASIAN J ORG CHEM 2022. [DOI: 10.1002/ajoc.202200060] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Aniruddha Paik
- University of North Bengal Department of Chemistry Raja Rammohunpur, DarjeelingWest Bengal, India - 734013 734013 Siliguri INDIA
| | - Sabarni Paul
- University of North Bengal Department of Chemistry Raja Rammohunpur, DarjeelingWest Bengal, India - 734013 734013 Siliguri INDIA
| | - Sabyasachi Bhowmik
- University of North Bengal Department of Chemistry Raja Rammohunpur, DarjeelingWest Bengal, India - 734013 734013 Siliguri INDIA
| | - Rahul Das
- University of North Bengal Department of Chemistry Raja Rammohunpur, DarjeelingWest Bengal, India - 734013 734013 Siliguri INDIA
| | - Togati Naveen
- Sardar Vallabhbhai National Institute of Technology Department of Chemistry 395007 Surat INDIA
| | - Sujoy Rana
- University of North Bengal Chemistry Raja Rammohunpur, DarjeelingWest Bengal, India, 734013 734013 Siliguri INDIA
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18
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Tetramethylammonium Fluoride: Fundamental Properties and Applications in C-F Bond-Forming Reactions and as a Base. Catalysts 2022. [DOI: 10.3390/catal12020233] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nucleophilic ionic sources of fluoride are essential reagents in the synthetic toolbox to access high added-value fluorinated building blocks unattainable by other means. In this review, we provide a concise description and rationale of the outstanding features of one of these reagents, tetramethylammonium fluoride (TMAF), as well as disclosing the different methods for its preparation, and how its physicochemical properties and solvation effects in different solvents are intimately associated with its reactivity. Furthermore, herein we also comprehensively describe its historic and recent utilization, up to December 2021, in C-F bond-forming reactions with special emphasis on nucleophilic aromatic substitution fluorinations with a potential sustainable application in industrial settings, as well as its use as a base capable of rendering unprecedented transformations.
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19
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Abstract
The fields of C-H functionalization and photoredox catalysis have garnered enormous interest and utility in the past several decades. Many different scientific disciplines have relied on C-H functionalization and photoredox strategies including natural product synthesis, drug discovery, radiolabeling, bioconjugation, materials, and fine chemical synthesis. In this Review, we highlight the use of photoredox catalysis in C-H functionalization reactions. We separate the review into inorganic/organometallic photoredox catalysts and organic-based photoredox catalytic systems. Further subdivision by reaction class─either sp2 or sp3 C-H functionalization─lends perspective and tactical strategies for use of these methods in synthetic applications.
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Affiliation(s)
- Natalie Holmberg-Douglas
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - David A Nicewicz
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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20
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Jiang YM, Yu Y, Wu SF, Yan H, Yuan Y, Ye KY. Electrochemical fluorosulfonylation of styrenes. Chem Commun (Camb) 2021; 57:11481-11484. [PMID: 34667999 DOI: 10.1039/d1cc04813a] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
An environmentally friendly and efficient electrochemical fluorosulfonylation of styrenes has been developed. With the use of sulfonylhydrazides and triethylamine trihydrofluoride, a diverse array of β-fluorosulfones could be readily obtained. This reaction features mild conditions and a broad substrate scope, which could also be conveniently extended to a gram-scale preparation.
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Affiliation(s)
- Yi-Min Jiang
- Key Laboratory of Molecule Synthesis and Function Discovery (Fujian Province University), College of Chemistry, Fuzhou University, Fuzhou 350108, China.
| | - Yi Yu
- Key Laboratory of Molecule Synthesis and Function Discovery (Fujian Province University), College of Chemistry, Fuzhou University, Fuzhou 350108, China.
| | - Shao-Fen Wu
- Key Laboratory of Molecule Synthesis and Function Discovery (Fujian Province University), College of Chemistry, Fuzhou University, Fuzhou 350108, China.
| | - Hong Yan
- Key Laboratory of Molecule Synthesis and Function Discovery (Fujian Province University), College of Chemistry, Fuzhou University, Fuzhou 350108, China.
| | - Yaofeng Yuan
- Key Laboratory of Molecule Synthesis and Function Discovery (Fujian Province University), College of Chemistry, Fuzhou University, Fuzhou 350108, China.
| | - Ke-Yin Ye
- Key Laboratory of Molecule Synthesis and Function Discovery (Fujian Province University), College of Chemistry, Fuzhou University, Fuzhou 350108, China. .,State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
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21
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Dong T, Tsui GC. Construction of Carbon-Fluorine Bonds via Copper-Catalyzed/-Mediated Fluorination Reactions. CHEM REC 2021; 21:4015-4031. [PMID: 34618399 DOI: 10.1002/tcr.202100231] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/20/2021] [Accepted: 09/20/2021] [Indexed: 01/09/2023]
Abstract
The construction of carbon-fluorine bonds is an important yet challenging task in organic synthesis. Transition metal-catalyzed/-mediated C-F bond forming processes have recently emerged as a viable strategy and provided access to value-added monofluorinated compounds. A dramatic increase in fluorination methods using inexpensive and earth-abundant copper can be seen in the past decade surpassing those using palladium and silver. This review discusses the recent development of Cu-catalyzed/-mediated formation of C(sp2 )-F and C(sp3 )-F bonds.
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Affiliation(s)
- Tao Dong
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Gavin Chit Tsui
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
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22
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23
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Transient directing ligands for selective metal-catalysed C–H activation. Nat Rev Chem 2021; 5:646-659. [PMID: 37118417 DOI: 10.1038/s41570-021-00311-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2021] [Indexed: 02/08/2023]
Abstract
C-H activation is a 'simple-to-complex' transformation that nature has perfected over millions of years of evolution. Transition-metal-catalysed C-H activation has emerged as an expeditious means to expand the chemical space by introducing diverse functionalities. Notably, among the strategies to selectively cleave a particular C-H bond, the catalytic use of a small molecule as co-catalyst to generate a transient directing group, which provides a balance between step economy and chemical productivity, has gained immense attention in recent years. This allows one to convert a desired C-H bond irrespective of its geometrical or stereochemical configuration. This Review describes the various transient directing groups used in C-H activation and explains their mechanistic significance.
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24
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Britton R, Gouverneur V, Lin JH, Meanwell M, Ni C, Pupo G, Xiao JC, Hu J. Contemporary synthetic strategies in organofluorine chemistry. ACTA ACUST UNITED AC 2021. [DOI: 10.1038/s43586-021-00042-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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25
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26
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Deng Z, Zhao Z, He G, Chen G. Photoredox-Mediated Mono- and Difluorination of Remote Unactivated Methylene C(sp 3)-H Bonds of N-Alkyl Sulfonamides. Org Lett 2021; 23:3631-3635. [PMID: 33881874 DOI: 10.1021/acs.orglett.1c01020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
A photoredox-mediated δ-C(sp3)-H fluorination of sulfonyl-protected primary alkylamines with Selectfluor is developed. The reaction can proceed in excellent monofluorination selectivity for amine substrates without α substituent. For α-substituted substrates, a slightly modified reaction conditions with two rounds of operation gives the δ,δ-difluorination products in good yield. Mechanistic studies suggest SET oxidation of sulfonamide group directly generates the key sulfonamide N radical intermediate, which triggers a 1,5-HAT process to form the δ alkyl radical.
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Affiliation(s)
- Zhiqiang Deng
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Zhenxiang Zhao
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Gang He
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Gong Chen
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
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27
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Matsumoto A, Wang Z, Maruoka K. Radical-Mediated Activation of Esters with a Copper/Selectfluor System: Synthesis of Bulky Amides and Peptides. J Org Chem 2021; 86:5401-5411. [PMID: 33720721 DOI: 10.1021/acs.joc.1c00188] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein, we describe a new approach for the activation of esters via a radical-mediated process enabled by a copper/Selectfluor system. A variety of para-methoxybenzyl esters derived from bulky carboxylic acids and amino acids can be easily converted into the corresponding acyl fluorides, directly used in the one-pot synthesis of amides and peptides. As a proof of concept, this method was applied to the iterative formation of sterically hindered amide bonds.
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Affiliation(s)
- Akira Matsumoto
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan
| | - Zhe Wang
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan
| | - Keiji Maruoka
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan.,School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China
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28
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Hu CC, Hu WQ, Xu XH, Qing FL. 2-Position-selective C H fluoromethylation of six-membered heteroaryl N-oxides with (fluoromethyl)triphenylphosphonium iodide. J Fluor Chem 2021. [DOI: 10.1016/j.jfluchem.2020.109695] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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29
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Muñoz-Molina JM, Belderrain TR, Pérez PJ. Recent Advances in Copper-Catalyzed Radical C–H Bond Activation Using N–F Reagents. SYNTHESIS-STUTTGART 2021. [DOI: 10.1055/s-0040-1707234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This Short Review is aimed at giving an update in the area of copper-catalyzed C–H functionalization involving nitrogen-centered radicals generated from substrates containing N–F bonds. These processes include intermolecular Csp3–H bond functionalization, remote Csp3–H bond functionalization via intramolecular hydrogen atom transfer (HAT), and Csp2–H bond functionalization, which might be of potential use in industrial applications in the future.1 Introduction2 Intermolecular Csp3–H Functionalization3 Remote Csp3–H Functionalization4 Csp2–H Functionalization5 Conclusion
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Affiliation(s)
| | | | - Pedro J. Pérez
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva
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30
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Feng Z, Zhu B, Dong B, Cheng L, Li Y, Wang Z, Wu J. Visible-Light-Promoted Synthesis of α-CF2H-Substituted Ketones by Radical Difluoromethylation of Enol Acetates. Org Lett 2020; 23:508-513. [DOI: 10.1021/acs.orglett.0c04021] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Zengqiang Feng
- College of Chemistry and Institute of Green Catalysis, Zhengzhou University, Zhengzhou 450001, P.R. China
| | - Baoxiang Zhu
- College of Chemistry and Institute of Green Catalysis, Zhengzhou University, Zhengzhou 450001, P.R. China
| | - Bingbing Dong
- College of Chemistry and Institute of Green Catalysis, Zhengzhou University, Zhengzhou 450001, P.R. China
| | - Li Cheng
- College of Chemistry and Institute of Green Catalysis, Zhengzhou University, Zhengzhou 450001, P.R. China
| | - Yunpu Li
- College of Chemistry and Institute of Green Catalysis, Zhengzhou University, Zhengzhou 450001, P.R. China
| | - Zechao Wang
- Division of Molecular Catalysis & Synthesis, Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450001, P.R. China
| | - Junliang Wu
- College of Chemistry and Institute of Green Catalysis, Zhengzhou University, Zhengzhou 450001, P.R. China
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31
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Shu C, Feng J, Zheng H, Cheng C, Yuan Z, Zhang Z, Xue XS, Zhu G. Internal Alkyne-Directed Fluorination of Unactivated C(sp 3)-H Bonds. Org Lett 2020; 22:9398-9403. [PMID: 33226830 DOI: 10.1021/acs.orglett.0c03730] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A silver-mediated internal alkyne-guided fluorination of unactivated C(sp3)-H bonds is described. The reaction provides a facile access to γ-fluorinated fluoroalkylated (Z)-alkenes from readily available alkynes in promising yields with excellent regioselectivity, stereoselectivity, and site selectivity.
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Affiliation(s)
- Chenyun Shu
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua 321004, P. R. China
| | - Jian Feng
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua 321004, P. R. China
| | - Hanliang Zheng
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Cungui Cheng
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua 321004, P. R. China
| | - Zheliang Yuan
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua 321004, P. R. China
| | - Zuxiao Zhang
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua 321004, P. R. China
| | - Xiao-Song Xue
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Gangguo Zhu
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua 321004, P. R. China
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32
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Barday M, Blieck R, Ruyet L, Besset T. Remote trifluoromethylthiolation of alcohols under visible light. Tetrahedron 2020. [DOI: 10.1016/j.tet.2020.131153] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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33
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Yakubov S, Barham JP. Photosensitized direct C-H fluorination and trifluoromethylation in organic synthesis. Beilstein J Org Chem 2020; 16:2151-2192. [PMID: 32952732 PMCID: PMC7476599 DOI: 10.3762/bjoc.16.183] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/17/2020] [Indexed: 12/11/2022] Open
Abstract
The importance of fluorinated products in pharmaceutical and medicinal chemistry has necessitated the development of synthetic fluorination methods, of which direct C-H fluorination is among the most powerful. Despite the challenges and limitations associated with the direct fluorination of unactivated C-H bonds, appreciable advancements in manipulating the selectivity and reactivity have been made, especially via transition metal catalysis and photochemistry. Where transition metal catalysis provides one strategy for C-H bond activation, transition-metal-free photochemical C-H fluorination can provide a complementary selectivity via a radical mechanism that proceeds under milder conditions than thermal radical activation methods. One exciting development in C-F bond formation is the use of small-molecule photosensitizers, allowing the reactions i) to proceed under mild conditions, ii) to be user-friendly, iii) to be cost-effective and iv) to be more amenable to scalability than typical photoredox-catalyzed methods. In this review, we highlight photosensitized C-H fluorination as a recent strategy for the direct and remote activation of C-H (especially C(sp3)-H) bonds. To guide the readers, we present the developing mechanistic understandings of these reactions and exemplify concepts to assist the future planning of reactions.
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Affiliation(s)
- Shahboz Yakubov
- Fakultät für Chemie und Pharmazie, Universität Regensburg, Universitätsstraße 31, 93040 Regensburg, Germany
| | - Joshua P Barham
- Fakultät für Chemie und Pharmazie, Universität Regensburg, Universitätsstraße 31, 93040 Regensburg, Germany
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34
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Ghorbani F, Harry SA, Capilato JN, Pitts CR, Joram J, Peters GN, Tovar JD, Smajlagic I, Siegler MA, Dudding T, Lectka T. Carbonyl-Directed Aliphatic Fluorination: A Special Type of Hydrogen Atom Transfer Beats Out Norrish II. J Am Chem Soc 2020; 142:14710-14724. [PMID: 32786786 DOI: 10.1021/jacs.0c07004] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Recently, our group reported that enone and ketone functional groups, upon photoexcitation, can direct site-selective sp3 C-H fluorination in terpenoid derivatives. How this transformation actually occurred remained mysterious, as a significant number of mechanistic possibilities came to mind. Herein, we report a comprehensive study describing the reaction mechanism through kinetic studies, isotope-labeling experiments, 19F NMR, electrochemical studies, synthetic probes, and computational experiments. To our surprise, the mechanism suggests intermolecular hydrogen atom transfer (HAT) chemistry is at play, rather than classical Norrish hydrogen atom abstraction as initially conceived. What is more, we discovered a unique role for photopromoters such as benzil and related compounds that necessitates their chemical transformation through fluorination in order to be effective. Our findings provide documentation of an unusual form of directed HAT and are of crucial importance for defining the necessary parameters for the development of future methods.
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Affiliation(s)
- Fereshte Ghorbani
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Stefan Andrew Harry
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Joseph N Capilato
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Cody Ross Pitts
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Jacob Joram
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Garvin N Peters
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - John D Tovar
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Ivor Smajlagic
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Maxime A Siegler
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Travis Dudding
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Thomas Lectka
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
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35
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Bafaluy D, Georgieva Z, Muñiz K. Iodine Catalysis for C(sp 3 )-H Fluorination with a Nucleophilic Fluorine Source. Angew Chem Int Ed Engl 2020; 59:14241-14245. [PMID: 32421217 DOI: 10.1002/anie.202004902] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Indexed: 01/13/2023]
Abstract
Iodine catalysis was developed for aliphatic fluorination through light-promoted homolytic C-H bond cleavage. The intermediary formation of amidyl radicals enables selective C-H functionalization via carbon-centered radicals. For the subsequent C-F bond formation, previous methods have typically been limited by a requirement for electrophilic fluorine reagents. We here demonstrate that the intermediary instalment of a carbon-iodine bond sets the stage for an umpolung, thereby establishing an unprecedented nucleophilic fluorination pathway.
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Affiliation(s)
- Daniel Bafaluy
- Institute of Chemical Research of Catalonia, ICIQ, The Barcelona Institute of Science and Technology, Av. Països Catalans, 16, 43007, Tarragona, Spain
| | - Zoritsa Georgieva
- Institute of Chemical Research of Catalonia, ICIQ, The Barcelona Institute of Science and Technology, Av. Països Catalans, 16, 43007, Tarragona, Spain
| | - Kilian Muñiz
- Institute of Chemical Research of Catalonia, ICIQ, The Barcelona Institute of Science and Technology, Av. Països Catalans, 16, 43007, Tarragona, Spain
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36
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Zhang Y, Ren Z, Liu Y, Wang Z, Li Z. Fluoroalkylation of Allylic Alcohols with Concomitant (Hetero)aryl Migration: Access to Fluoroalkylated Ketones and Evaluation of Antifungal Action against
Magnaporthe grisea. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000782] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Yanhu Zhang
- Department of Applied Chemistry College of Materials and Energy South China Agricultural University 510642 Guangzhou China
| | - Ziyang Ren
- Department of Applied Chemistry College of Materials and Energy South China Agricultural University 510642 Guangzhou China
| | - Yun‐Lin Liu
- School of Chemistry and Chemical Engineering Guangzhou University 230 Wai Huan Xi Road 510006 Guangzhou China
| | - Zhentao Wang
- College of Chemistry and Material Science Shandong Agricultural University 271018 Taian Shandong China
| | - Zhaodong Li
- Department of Applied Chemistry College of Materials and Energy South China Agricultural University 510642 Guangzhou China
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37
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Buss JA, Vasilopoulos A, Golden DL, Stahl SS. Copper-Catalyzed Functionalization of Benzylic C-H Bonds with N-Fluorobenzenesulfonimide: Switch from C-N to C-F Bond Formation Promoted by a Redox Buffer and Brønsted Base. Org Lett 2020; 22:5749-5752. [PMID: 32790419 PMCID: PMC7446155 DOI: 10.1021/acs.orglett.0c02239] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A copper catalyst in combination with N-fluorobenzenesulfonimide (NFSI) has been reported to functionalize benzylic C-H bonds to the corresponding benzylic sulfonimides via C-N coupling. Here, we reported a closely related Cu-catalyzed method with NFSI that instead leads to C-F coupling. This switch in selectivity arises from changes to the reaction conditions (Cu/ligand ratio, temperature, addition of base) and further benefits from inclusion of MeB(OH)2 in the reaction. MeB(OH)2 is shown to serve as a "redox buffer" in the reaction, responsible for rescuing inactive Cu(II) for continued promotion of fluorination reactivity.
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Affiliation(s)
- Joshua A. Buss
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, United States
| | - Aristidis Vasilopoulos
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, United States
| | - Dung L. Golden
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, United States
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, United States
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38
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Bafaluy D, Georgieva Z, Muñiz K. Iodine Catalysis for C(sp
3
)–H Fluorination with a Nucleophilic Fluorine Source. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202004902] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Daniel Bafaluy
- Institute of Chemical Research of Catalonia, ICIQ The Barcelona Institute of Science and Technology Av. Països Catalans, 16 43007 Tarragona Spain
| | - Zoritsa Georgieva
- Institute of Chemical Research of Catalonia, ICIQ The Barcelona Institute of Science and Technology Av. Països Catalans, 16 43007 Tarragona Spain
| | - Kilian Muñiz
- Institute of Chemical Research of Catalonia, ICIQ The Barcelona Institute of Science and Technology Av. Països Catalans, 16 43007 Tarragona Spain
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39
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Artault M, Mokhtari N, Cantin T, Martin-Mingot A, Thibaudeau S. Superelectrophilic Csp 3-H bond fluorination of aliphatic amines in superacid: the striking role of ammonium-carbenium dications. Chem Commun (Camb) 2020; 56:5905-5908. [PMID: 32342071 DOI: 10.1039/d0cc02081h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The superacid-promoted electrophilic Csp3-H bond activation of aliphatic amines generates superelectrophilic species that can be subsequently fluorinated. Demonstrated by low-temperature in situ NMR experiments, the ammonium-carbenium dications, crucial for this reaction, can also react with C-H bonds opening future synthesis perspectives for this mode of activation.
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Affiliation(s)
- M Artault
- Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers, CNRS, Superacid Group in Organic Synthesis Team, F-86073 Poitiers, France.
| | - N Mokhtari
- Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers, CNRS, Superacid Group in Organic Synthesis Team, F-86073 Poitiers, France.
| | - T Cantin
- Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers, CNRS, Superacid Group in Organic Synthesis Team, F-86073 Poitiers, France.
| | - A Martin-Mingot
- Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers, CNRS, Superacid Group in Organic Synthesis Team, F-86073 Poitiers, France.
| | - S Thibaudeau
- Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers, CNRS, Superacid Group in Organic Synthesis Team, F-86073 Poitiers, France.
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40
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Aguilar Troyano FJ, Merkens K, Gómez‐Suárez A. Selectfluor® Radical Dication (TEDA
2+.
) – A Versatile Species in Modern Synthetic Organic Chemistry. ASIAN J ORG CHEM 2020. [DOI: 10.1002/ajoc.202000196] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
| | - Kay Merkens
- Organic ChemistryBergische Universität Wuppertal Gaußstr. 20 42119 Wuppertal Germany
| | - Adrián Gómez‐Suárez
- Organic ChemistryBergische Universität Wuppertal Gaußstr. 20 42119 Wuppertal Germany
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41
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Lv S, Yan X, Li C, Zhou S, Shoberu A, Zou J. Copper‐Catalyzed
sp
3
‐Carbon Radical/Halogen Radical Cross Coupling: Selective Halogenation of 1,3‐Dicarbonyl Compounds. ChemistrySelect 2020. [DOI: 10.1002/slct.202000947] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Shuai‐Shuai Lv
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Material Sciences Soochow University Suzhou, Jiangsu 215123 China
| | - Xu‐Ping Yan
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Material Sciences Soochow University Suzhou, Jiangsu 215123 China
| | - Cheng‐Kun Li
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Material Sciences Soochow University Suzhou, Jiangsu 215123 China
| | - Shao‐Fang Zhou
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Material Sciences Soochow University Suzhou, Jiangsu 215123 China
| | - Adedamola Shoberu
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Material Sciences Soochow University Suzhou, Jiangsu 215123 China
| | - Jian‐Ping Zou
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Material Sciences Soochow University Suzhou, Jiangsu 215123 China
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42
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Bower JK, Cypcar AD, Henriquez B, Stieber SCE, Zhang S. C(sp 3)-H Fluorination with a Copper(II)/(III) Redox Couple. J Am Chem Soc 2020; 142:8514-8521. [PMID: 32275410 DOI: 10.1021/jacs.0c02583] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Despite the growing interest in the synthesis of fluorinated organic compounds, few reactions are able to incorporate fluoride ions directly into alkyl C-H bonds. Here, we report the C(sp3)-H fluorination reactivity of a formally copper(III) fluoride complex. The C-H fluorination intermediate, LCuF, along with its chloride and bromide analogues, LCuCl and LCuBr, were prepared directly from halide sources with a chemical oxidant and fully characterized with single-crystal X-ray diffraction, X-ray absorption spectroscopy, UV-vis spectroscopy, and 1H nuclear magnetic resonance spectroscopy. Quantum chemical calculations reveal significant halide radical character for all complexes, suggesting their ability to initiate and terminate a C(sp3)-H halogenation sequence by sequential hydrogen atom abstraction (HAA) and radical capture. The capability of HAA by the formally copper(III) halide complexes was explored with 9,10-dihydroanthracene, revealing that LCuF exhibits rates 2 orders of magnitude higher than LCuCl and LCuBr. In contrast, all three complexes efficiently capture carbon radicals to afford C(sp3)-halogen bonds. Mechanistic investigation of radical capture with a triphenylmethyl radical revealed that LCuF proceeds through a concerted mechanism, while LCuCl and LCuBr follow a stepwise electron transfer-halide transfer pathway. The capability of LCuF to perform both hydrogen atom abstraction and radical capture was leveraged to enable fluorination of allylic and benzylic C-H bonds and α-C-H bonds of ethers at room temperature.
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Affiliation(s)
- Jamey K Bower
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Andrew D Cypcar
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Brenda Henriquez
- Department of Chemistry & Biochemistry, California State Polytechnic University, Pomona, 3801 West Temple Avenue, Pomona, California 91768, United States
| | - S Chantal E Stieber
- Department of Chemistry & Biochemistry, California State Polytechnic University, Pomona, 3801 West Temple Avenue, Pomona, California 91768, United States
| | - Shiyu Zhang
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
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43
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Guo P, Li Y, Zhang XG, Han JF, Yu Y, Zhu J, Ye KY. Redox Neutral Radical-Relay Cobalt Catalysis toward C-H Fluorination and Amination. Org Lett 2020; 22:3601-3606. [PMID: 32307998 DOI: 10.1021/acs.orglett.0c01072] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A redox neutral radical-relay cobalt-catalyzed intramolecular C-H fluorination of N-fluoroamides featuring the in situ formed cobalt fluorides as the latent radical fluorinating agents is reported. Moreover, the reactivity of such a cobalt catalysis could be diverted from C-H fluorination to amination by engineering substrates' conformational flexibility. Preliminary mechanistic studies (UV-vis spectroscopy, cyclic voltammetry studies and DFT calculations, etc.) support the reaction proceeding a redox neutral radical-relay mechanism.
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Affiliation(s)
- Peng Guo
- Key Laboratory of Molecule Synthesis and Function Discovery (Fujian Province University), College of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Yuanyuan Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiang-Gui Zhang
- Key Laboratory of Molecule Synthesis and Function Discovery (Fujian Province University), College of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Jun-Fa Han
- Key Laboratory of Molecule Synthesis and Function Discovery (Fujian Province University), College of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Yi Yu
- Key Laboratory of Molecule Synthesis and Function Discovery (Fujian Province University), College of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Ke-Yin Ye
- Key Laboratory of Molecule Synthesis and Function Discovery (Fujian Province University), College of Chemistry, Fuzhou University, Fuzhou 350108, China
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44
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Capilato JN, Pitts CR, Rowshanpour R, Dudding T, Lectka T. Site-Selective Photochemical Fluorination of Ketals: Unanticipated Outcomes in Selectivity and Stability. J Org Chem 2020; 85:2855-2864. [PMID: 32031800 DOI: 10.1021/acs.joc.9b03047] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a method for the regioselective photochemical sp3 C-H fluorination of acetonide ketals that presents interesting problems in chemical reactivity. The question of why certain products of the reaction are stable while others are not is addressed, as is the question of why only select α-ethereal hydrogen atoms are targeted in the reaction. We demonstrate that the method can be employed to synthesize unprecedented fluorinated sugars and steroids, and it can also be applied toward the fluorination of carbamates. Though some substrates contain up to eight discrete α-ethereal C-H bonds, we observed site-selectivity in each case, prompting us to investigate potential transition states for the reaction. Finally, a remarkable regiochemical switch upon minor structural modification of a diketal is also analyzed.
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Affiliation(s)
- Joseph N Capilato
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Cody Ross Pitts
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Rozhin Rowshanpour
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
| | - Travis Dudding
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
| | - Thomas Lectka
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
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45
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Kacem S, Emondts M, Bordet A, Leitner W. Selective hydrogenation of fluorinated arenes using rhodium nanoparticles on molecularly modified silica. Catal Sci Technol 2020. [DOI: 10.1039/d0cy01716g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rh nanoparticles prepared on hydrophobic molecularly modified silica act as effective catalysts for the hydrogenation of fluoroarenes to fluorocyclohexane derivatives.
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Affiliation(s)
- Souha Kacem
- Max Planck Institute for Chemical Energy Conversion
- 45470 Mülheim an der Ruhr
- Germany
- Institut für Technische und Makromolekulare Chemie
- RWTH Aachen University
| | - Meike Emondts
- Institut für Technische und Makromolekulare Chemie
- RWTH Aachen University
- 52074 Aachen
- Germany
- DWI-Leibniz Institute for Interactive Materials
| | - Alexis Bordet
- Max Planck Institute for Chemical Energy Conversion
- 45470 Mülheim an der Ruhr
- Germany
| | - Walter Leitner
- Max Planck Institute for Chemical Energy Conversion
- 45470 Mülheim an der Ruhr
- Germany
- Institut für Technische und Makromolekulare Chemie
- RWTH Aachen University
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46
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Pinter EN, Bingham JE, AbuSalim DI, Cook SP. N-Directed fluorination of unactivated Csp 3-H bonds. Chem Sci 2019; 11:1102-1106. [PMID: 34084366 PMCID: PMC8146735 DOI: 10.1039/c9sc04055b] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Site-selective fluorination of aliphatic C-H bonds remains synthetically challenging. While directed C-H fluorination represents the most promising approach, the limited work conducted to date has enabled just a few functional groups as the arbiters of direction. Leveraging insights gained from both computations and experimentation, we enabled the use of the ubiquitous amine functional group as a handle for the directed C-H fluorination of Csp3-H bonds. By converting primary amines to adamantoyl-based fluoroamides, site-selective C-H fluorination proceeds under the influence of a simple iron catalyst in 20 minutes. Computational studies revealed a unique reaction coordinate for the catalytic process and offer an explanation for the high site selectivity.
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Affiliation(s)
- Emily N Pinter
- Department of Chemistry, Indiana University 800 East Kirkwood Avenue Bloomington IN 47405-7102 USA
| | - Jenna E Bingham
- Department of Chemistry, Indiana University 800 East Kirkwood Avenue Bloomington IN 47405-7102 USA
| | - Deyaa I AbuSalim
- Department of Chemistry, Indiana University 800 East Kirkwood Avenue Bloomington IN 47405-7102 USA
| | - Silas P Cook
- Department of Chemistry, Indiana University 800 East Kirkwood Avenue Bloomington IN 47405-7102 USA
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47
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Aguilar Troyano FJ, Ballaschk F, Jaschinski M, Özkaya Y, Gómez‐Suárez A. Light-Mediated Formal Radical Deoxyfluorination of Tertiary Alcohols through Selective Single-Electron Oxidation with TEDA 2+.. Chemistry 2019; 25:14054-14058. [PMID: 31452265 PMCID: PMC6899844 DOI: 10.1002/chem.201903702] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Indexed: 01/28/2023]
Abstract
The synthesis of tertiary alkyl fluorides through a formal radical deoxyfluorination process is described herein. This light-mediated, catalyst-free methodology is fast and broadly applicable allowing for the preparation of C-F bonds from (hetero)benzylic, propargylic, and non-activated tertiary alcohol derivatives. Preliminary mechanistic studies support that the key step of the reaction is the single-electron oxidation of cesium oxalates-which are readily available from the corresponding tertiary alcohols-with in situ generated TEDA2+. (TEDA: N-(chloromethyl)triethylenediamine), a radical cation derived from Selectfluor®.
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Affiliation(s)
| | - Frederic Ballaschk
- Organic ChemistryBergische Universität WuppertalGaußstrasse 2042119WuppertalGermany
| | - Marcel Jaschinski
- Organic ChemistryBergische Universität WuppertalGaußstrasse 2042119WuppertalGermany
| | - Yasemin Özkaya
- Organic ChemistryBergische Universität WuppertalGaußstrasse 2042119WuppertalGermany
| | - Adrián Gómez‐Suárez
- Organic ChemistryBergische Universität WuppertalGaußstrasse 2042119WuppertalGermany
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48
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Li X, Shi X, Li X, Shi D. Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups. Beilstein J Org Chem 2019; 15:2213-2270. [PMID: 31598178 PMCID: PMC6774084 DOI: 10.3762/bjoc.15.218] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 09/03/2019] [Indexed: 01/24/2023] Open
Abstract
Fluorine chemistry plays an increasingly important role in pharmaceutical, agricultural, and materials industries. The incorporation of fluorine-containing groups into organic molecules can improve their chemical and physical properties, which attracts continuous interest in organic synthesis. Among various reported methods, transition-metal-catalyzed fluorination/fluoroalkylation has emerged as a powerful method for the construction of these compounds. This review attempts to describe the major advances in the transition-metal-catalyzed incorporation of fluorine, trifluoromethyl, difluoromethyl, trifluoromethylthio, and trifluoromethoxy groups reported between 2011 and 2019.
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Affiliation(s)
- Xiaowei Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China.,Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao 266000, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaolin Shi
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China.,Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao 266000, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiangqian Li
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, China
| | - Dayong Shi
- State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Qingdao 266237, China
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49
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Szpera R, Moseley DFJ, Smith LB, Sterling AJ, Gouverneur V. Fluorierung von C‐H‐Bindungen: Entwicklungen und Perspektiven. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201814457] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Robert Szpera
- Chemistry Research Laboratory Oxford University 12 Mansfield Road Oxford OX1 3TA Großbritannien
| | - Daniel F. J. Moseley
- Chemistry Research Laboratory Oxford University 12 Mansfield Road Oxford OX1 3TA Großbritannien
| | - Lewis B. Smith
- Chemistry Research Laboratory Oxford University 12 Mansfield Road Oxford OX1 3TA Großbritannien
| | - Alistair J. Sterling
- Chemistry Research Laboratory Oxford University 12 Mansfield Road Oxford OX1 3TA Großbritannien
| | - Véronique Gouverneur
- Chemistry Research Laboratory Oxford University 12 Mansfield Road Oxford OX1 3TA Großbritannien
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50
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Szpera R, Moseley DFJ, Smith LB, Sterling AJ, Gouverneur V. The Fluorination of C-H Bonds: Developments and Perspectives. Angew Chem Int Ed Engl 2019; 58:14824-14848. [PMID: 30759327 DOI: 10.1002/anie.201814457] [Citation(s) in RCA: 246] [Impact Index Per Article: 49.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Indexed: 12/16/2022]
Abstract
This Review summarizes advances in fluorination by C(sp2 )-H and C(sp3 )-H activation. Transition-metal-catalyzed approaches championed by palladium have allowed the installation of a fluorine substituent at C(sp2 ) and C(sp3 ) sites, exploiting the reactivity of high-oxidation-state transition-metal fluoride complexes combined with the use of directing groups (some transient) to control site and stereoselectivity. The large majority of known methods employ electrophilic fluorination reagents, but methods combining a nucleophilic fluoride source with an oxidant have appeared. External ligands have proven to be effective for C(sp3 )-H fluorination directed by weakly coordinating auxiliaries, thereby enabling control over reactivity. Methods relying on the formation of radical intermediates are complementary to transition-metal-catalyzed processes as they allow for undirected C(sp3 )-H fluorination. To date, radical C-H fluorinations mainly employ electrophilic N-F fluorination reagents but a unique MnIII -catalyzed oxidative C-H fluorination using fluoride has been developed. Overall, the field of late-stage nucleophilic C-H fluorination has progressed much more slowly, a state of play explaining why C-H 18 F-fluorination is still in its infancy.
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Affiliation(s)
- Robert Szpera
- Chemistry Research Laboratory, Oxford University, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Daniel F J Moseley
- Chemistry Research Laboratory, Oxford University, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Lewis B Smith
- Chemistry Research Laboratory, Oxford University, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Alistair J Sterling
- Chemistry Research Laboratory, Oxford University, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Véronique Gouverneur
- Chemistry Research Laboratory, Oxford University, 12 Mansfield Road, Oxford, OX1 3TA, UK
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