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Sarkar N, Kumar Sahoo R, Ganesh Patro A, Nembenna S. Aluminum-Catalyzed Selective Hydroboration of Carbonyls and Dehydrocoupling of Alcohols, Phenols, Amines, Thiol, Selenol, Silanols with HBpin. Polyhedron 2022. [DOI: 10.1016/j.poly.2022.115902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
AbstractThe unique properties of fluorine-containing organic compounds make fluorine substitution attractive for the development of pharmaceuticals and various specialty materials, which have inspired the evolution of diverse C-F bond activation techniques. Although many advances have been made in functionalizations of activated C-F bonds utilizing transition metal complexes, there are fewer approaches available for nonactivated C-F bonds due to the difficulty in oxidative addition of transition metals to the inert C-F bonds. In this regard, using Lewis acid to abstract the fluoride and light/radical initiator to generate the radical intermediate have emerged as powerful tools for activating those inert C-F bonds. Meanwhile, these transition-metal-free processes are greener, economical, and for the pharmaceutical industry, without heavy metal residues. This review provides an overview of recent C-F bond activations and functionalizations under transition-metal-free conditions. The key mechanisms involved are demonstrated and discussed in detail. Finally, a brief discussion on the existing limitations of this field and our perspective are presented.
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3
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Joshi A, Collins S, Linnolahti M, Zijlstra HS, Liles E, McIndoe JS. Spectroscopic Studies of Synthetic Methylaluminoxane: Structure of Methylaluminoxane Activators. Chemistry 2021; 27:8753-8763. [PMID: 33780574 DOI: 10.1002/chem.202100271] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Indexed: 11/06/2022]
Abstract
Hydrolysis of trimethylaluminum (Me3 Al) in polar solvents can be monitored by electrospray ionization mass spectrometry (ESI-MS) using the donor additive octamethyltrisiloxane [(Me3 SiO)2 SiMe2 , OMTS]. Using hydrated salts, hydrolytic methylaluminoxane (h-MAO) features different anion distributions, depending on the conditions of synthesis, and different activator contents as measured by NMR spectroscopy. Non-hydrolytic MAO was prepared using trimethylboroxine. The properties of this material, which contains incorporated boron, differ significantly from h-MAO. In the case of MAO prepared by direct hydrolysis, oligomeric anions are observed to rapidly form, and then more slowly evolve into a mixture dominated by an anion with m/z 1375 with formula [(MeAlO)16 (Me3 Al)6 Me]- . Theoretical calculations predict that sheet structures with composition (MeAlO)n (Me3 Al)m are favoured over other motifs for MAO in the size range suggested by the ESI-MS experiments. A possible precursor to the m/z 1375 anion is a local minimum based on the free energy released upon hydrolysis of Me3 Al.
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Affiliation(s)
- Anuj Joshi
- Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
| | - Scott Collins
- C/o Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
| | - Mikko Linnolahti
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, Yliopistokatu 7, 80100, Joensuu, Finland
| | - Harmen S Zijlstra
- Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
| | - Elena Liles
- Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
| | - J Scott McIndoe
- Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
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Zaccaria F, Zuccaccia C, Cipullo R, Budzelaar PHM, Vittoria A, Macchioni A, Busico V, Ehm C. Methylaluminoxane’s Molecular Cousin: A Well-defined and “Complete” Al-Activator for Molecular Olefin Polymerization Catalysts. ACS Catal 2021. [DOI: 10.1021/acscatal.0c05696] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Francesco Zaccaria
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
- Dipartimento di Chimica, Biologia e Biotecnologie and CIRCC, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Cristiano Zuccaccia
- Dipartimento di Chimica, Biologia e Biotecnologie and CIRCC, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Roberta Cipullo
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Peter H. M. Budzelaar
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Antonio Vittoria
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Alceo Macchioni
- Dipartimento di Chimica, Biologia e Biotecnologie and CIRCC, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Vincenzo Busico
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Christian Ehm
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
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5
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Marczenko KM, Jee S, Chitnis SS. High Lewis Acidity at Planar, Trivalent, and Neutral Bismuth Centers. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00378] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Katherine M. Marczenko
- Department of Chemistry, Dalhousie University, 6274 Coburg Road, Halifax, Nova Scotia B3H 4R2, Canada
| | - Samantha Jee
- Department of Chemistry, Dalhousie University, 6274 Coburg Road, Halifax, Nova Scotia B3H 4R2, Canada
| | - Saurabh S. Chitnis
- Department of Chemistry, Dalhousie University, 6274 Coburg Road, Halifax, Nova Scotia B3H 4R2, Canada
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Wang J, Ogawa Y, Shibata N. Activation of Saturated Fluorocarbons to Synthesize Spirobiindanes, Monofluoroalkenes, and Indane Derivatives. iScience 2019; 17:132-143. [PMID: 31276957 PMCID: PMC6612000 DOI: 10.1016/j.isci.2019.06.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 06/03/2019] [Accepted: 06/12/2019] [Indexed: 12/15/2022] Open
Abstract
Fluorinated organic compounds are produced in abundance by the pharmaceutical and agrochemical industry, making such compounds attractive as building blocks for further functionalization. Unfortunately, activation of C(sp3)-F bond in saturated fluorocarbons, especially for aliphatic gem-difluoroalkanes, remains challenging. Here we describe the selective activation of inert C(sp3)-F bonds catalyzed by B(C6F5)3. In hexafluoro-2-propanol (HFIP), chemically robust aliphatic gem-difluorides are converted in high yields to the corresponding substituted 2,2′,3,3′-tetrahydro-1,1′-spirobiindenes via a B(C6F5)3-catalyzed intramolecular cascade Friedel-Crafts cyclization, not requiring a silicon-based trapping reagent. However, in the absence of a hydrogen-bonding donor solvent such as HFIP, the aliphatic gem-difluorides preferentially engage in a defluorination/elimination process that provides monofluorinated alkenes in good yields. Furthermore, a series of substituted 1-alkyl-2,3-dihydro-1H-indenes was obtained in high yield from the B(C6F5)3-catalyzed defluorinative cyclization of aliphatic secondary monofluorides in HFIP. The protocol could inspire development of a new class of main-group Lewis acid-catalyzed C(sp3)-F bond activation in general unactivated fluorocarbons. C(sp3)-F bond activation in general unactivated fluorocarbons The activation of C(sp3)-F bonds in aliphatic gem-difluoroalkanes The selective activation of inert C(sp3)-F bonds catalyzed by B(C6F5)3 An intramolecular cascade defluorinative Friedel-Crafts cyclization
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Affiliation(s)
- Jiandong Wang
- Department of Nanopharmaceutical Sciences and Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-5888, Japan
| | - Yuta Ogawa
- Department of Nanopharmaceutical Sciences and Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-5888, Japan
| | - Norio Shibata
- Department of Nanopharmaceutical Sciences and Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-5888, Japan; Institute of Advanced Fluorine-Containing Materials, Zhejiang Normal University, 688 Yingbin Avenue, 321004 Jinhua, China.
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7
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Fisher SP, Tomich AW, Lovera SO, Kleinsasser JF, Guo J, Asay MJ, Nelson HM, Lavallo V. Nonclassical Applications of closo-Carborane Anions: From Main Group Chemistry and Catalysis to Energy Storage. Chem Rev 2019; 119:8262-8290. [PMID: 30707011 DOI: 10.1021/acs.chemrev.8b00551] [Citation(s) in RCA: 173] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Classically closo-carborane anions, particularly [HCB11H11]- and [HCB9H9]-, and their derivatives have primarily been used as weakly coordinating anions to isolate reactive intermediates, platforms for stoichiometric and catalytic functionalization, counteranions for simple Lewis acid catalysis, and components of materials like liquid crystals. The aim of this article is to educate the reader on the contemporary nonclassical applications of these anions. Specifically, this review will cover new directions in main group catalysis utilized to achieve some of the most challenging catalytic reactions such as C-F, C-H, and C-C functionalizations that are difficult or impossible to realize with transition metals. In addition, the review will cover the utilization of the clusters as dianionic C σ-bound ligands for coordination chemistry, ligand substituents for coordination chemistry and advanced catalyst design, and covalently bound spectator substituents to stabilize radicals. Furthermore, their applications as solution-based and solid-state electrolytes for Li, Na, and Mg batteries will be discussed.
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Affiliation(s)
- S P Fisher
- Department of Chemistry , University of California, Riverside , 501 Big Springs Road , Riverside , California 92521 , United States
| | - A W Tomich
- Department of Chemistry , University of California, Riverside , 501 Big Springs Road , Riverside , California 92521 , United States
| | - S O Lovera
- Department of Chemistry , University of California, Riverside , 501 Big Springs Road , Riverside , California 92521 , United States
| | - J F Kleinsasser
- Department of Chemistry , University of California, Riverside , 501 Big Springs Road , Riverside , California 92521 , United States
| | - J Guo
- Department of Chemical and Environmental Engineering , University of California, Riverside , Riverside , California 92521 , United States
| | - M J Asay
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - H M Nelson
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - V Lavallo
- Department of Chemistry , University of California, Riverside , 501 Big Springs Road , Riverside , California 92521 , United States
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Jaeger AD, Walter R, Ehm C, Lentz D. Gallium Hydrides and O/N-Donors as Tunable Systems in C-F Bond Activation. Chem Asian J 2018; 13:2908-2915. [PMID: 30028089 DOI: 10.1002/asia.201801030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Indexed: 12/15/2022]
Abstract
The gallium hydrides (iBu)2 GaH (1 a), LiGaH4 (1 b) and Me3 N⋅GaH3 (1 c) hydrodefluorinate vinylic and aromatic C-F bonds when O and N donor molecules are present. 1 b exhibits the highest reactivity. Quantitative conversion to the hydrodefluorination (HDF) products could be observed for hexafluoropropene and 1,1,3,3,3-pentafluoropropene, 94 % conversion of pentafluoropyridine and 49 % of octafluorotoluene. Whereas for the HDF with 1 b high conversions are observed when catalytic amounts of O donor molecules are added, for 1 a, the addition of N donor molecules lead to higher conversions. The E/Z selectivity of the HDF of 1,1,3,3,3-pentafluoropropene is donor-dependent. DFT studies show that HDF proceeds in this case via the gallium hydride dimer-donor species and a hydrometallation/elimination sequence. Selectivities are sensitive to the choice of donor, as the right donor can lead to an on/off switching during catalysis, that is, the hydrometallation step is accelerated by the presence of a donor, but the donor dissociates prior to elimination, allowing the inherently more selective donorless gallium systems to determine the selectivity.
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Affiliation(s)
- Alma D Jaeger
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstr. 34-36, 14195, Berlin, Germany
| | - Ruben Walter
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstr. 34-36, 14195, Berlin, Germany
| | - Christian Ehm
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126, Napoli, Italy
| | - Dieter Lentz
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstr. 34-36, 14195, Berlin, Germany
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9
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Schneider H, Hock A, Jaeger AD, Lentz D, Radius U. NHC·Alane Adducts as Hydride Sources in the Hydrodefluorination of Fluoroaromatics and Fluoroolefins. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201800589] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Heidi Schneider
- Institut für Anorganische Chemie Julius‐Maximilians‐Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Andreas Hock
- Institut für Anorganische Chemie Julius‐Maximilians‐Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Alma D. Jaeger
- Institut für Chemie und Biochemie ‐ Anorganische Chemie Freie Universität Berlin Fabeckstr. 34–36 14195 Berlin Germany
| | - Dieter Lentz
- Institut für Chemie und Biochemie ‐ Anorganische Chemie Freie Universität Berlin Fabeckstr. 34–36 14195 Berlin Germany
| | - Udo Radius
- Institut für Anorganische Chemie Julius‐Maximilians‐Universität Würzburg Am Hubland 97074 Würzburg Germany
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10
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Mandal D, Gupta R, Young RD. Selective Monodefluorination and Wittig Functionalization of gem-Difluoromethyl Groups to Generate Monofluoroalkenes. J Am Chem Soc 2018; 140:10682-10686. [PMID: 30119600 DOI: 10.1021/jacs.8b06770] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Monodefluorination of gem-difluoromethyl groups is achieved using a frustrated Lewis pair (FLP) approach. Triarylphosphines and group 13 Lewis acids were surveyed as FLP components, with the combination of P( o-Tol)3 and B(C6F5)3 found to provide the best results, although the reaction is feasible with more economical components (PPh3 and BF3·OEt2). The α-fluoroalkylphosphonium products arising from the reaction were of lower activity, in regard to further fluoride abstraction, as compared to difluoride starting materials, leading to highly selective monodefluorination. The activated substrates were subject to Wittig reaction protocols to generate a variety of monofluoroalkenes in moderate to high yields.
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Affiliation(s)
- Dipendu Mandal
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , Singapore 117543 , Singapore
| | - Richa Gupta
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , Singapore 117543 , Singapore
| | - Rowan D Young
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , Singapore 117543 , Singapore
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11
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Chitnis SS, Krischer F, Stephan DW. Catalytic Hydrodefluorination of C−F Bonds by an Air-Stable PIII
Lewis Acid. Chemistry 2018; 24:6543-6546. [DOI: 10.1002/chem.201801305] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Indexed: 01/05/2023]
Affiliation(s)
- Saurabh S. Chitnis
- Department of Chemistry; University of Toronto; 80 St. George St. Toronto Ontario M5S3H6 Canada
| | - Felix Krischer
- Department of Chemistry; University of Toronto; 80 St. George St. Toronto Ontario M5S3H6 Canada
| | - Douglas W. Stephan
- Department of Chemistry; University of Toronto; 80 St. George St. Toronto Ontario M5S3H6 Canada
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12
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Jaeger AD, Ehm C, Lentz D. Organocatalytic C−F Bond Activation with Alanes. Chemistry 2018; 24:6769-6777. [DOI: 10.1002/chem.201706061] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 02/13/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Alma D. Jaeger
- Freie Universität Berlin; Institut für Chemie und Biochemie, Anorganische Chemie; Fabeckstr. 34-36 14195 Berlin Germany
| | - Christian Ehm
- Università di Napoli Federico II; Dipartimento di Scienze Chimiche; Via Cintia 80126 Napoli Italy
| | - Dieter Lentz
- Freie Universität Berlin; Institut für Chemie und Biochemie, Anorganische Chemie; Fabeckstr. 34-36 14195 Berlin Germany
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13
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Meißner G, Kretschmar K, Braun T, Kemnitz E. Consecutive Transformations of Tetrafluoropropenes: Hydrogermylation and Catalytic C−F Activation Steps at a Lewis Acidic Aluminum Fluoride. Angew Chem Int Ed Engl 2017; 56:16338-16341. [DOI: 10.1002/anie.201707759] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/01/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Gisa Meißner
- Department of Chemistry; Humboldt-Universität zu Berlin; Brook-Taylor-Strasse 2 12489 Berlin Germany
| | - Konrad Kretschmar
- Department of Chemistry; Humboldt-Universität zu Berlin; Brook-Taylor-Strasse 2 12489 Berlin Germany
| | - Thomas Braun
- Department of Chemistry; Humboldt-Universität zu Berlin; Brook-Taylor-Strasse 2 12489 Berlin Germany
| | - Erhard Kemnitz
- Department of Chemistry; Humboldt-Universität zu Berlin; Brook-Taylor-Strasse 2 12489 Berlin Germany
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14
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Meißner G, Kretschmar K, Braun T, Kemnitz E. Consecutive Transformations of Tetrafluoropropenes: Hydrogermylation and Catalytic C−F Activation Steps at a Lewis Acidic Aluminum Fluoride. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201707759] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gisa Meißner
- Department of Chemistry; Humboldt-Universität zu Berlin; Brook-Taylor-Strasse 2 12489 Berlin Germany
| | - Konrad Kretschmar
- Department of Chemistry; Humboldt-Universität zu Berlin; Brook-Taylor-Strasse 2 12489 Berlin Germany
| | - Thomas Braun
- Department of Chemistry; Humboldt-Universität zu Berlin; Brook-Taylor-Strasse 2 12489 Berlin Germany
| | - Erhard Kemnitz
- Department of Chemistry; Humboldt-Universität zu Berlin; Brook-Taylor-Strasse 2 12489 Berlin Germany
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15
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Forster F, Metsänen TT, Irran E, Hrobárik P, Oestreich M. Cooperative Al–H Bond Activation in DIBAL-H: Catalytic Generation of an Alumenium-Ion-Like Lewis Acid for Hydrodefluorinative Friedel–Crafts Alkylation. J Am Chem Soc 2017; 139:16334-16342. [DOI: 10.1021/jacs.7b09444] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Francis Forster
- Institut
für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
| | - Toni T. Metsänen
- Institut
für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
| | - Elisabeth Irran
- Institut
für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
| | - Peter Hrobárik
- Institut
für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
- Department
of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, 84215 Bratislava, Slovakia
| | - Martin Oestreich
- Institut
für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
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Affiliation(s)
- Georgii I. Nikonov
- Department of Chemistry, Brock University, 1812
Sir Isaac Brock Way, St. Catharines, Ontario, Canada L2S 3A1
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17
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Munoz SB, Ni C, Zhang Z, Wang F, Shao N, Mathew T, Olah GA, Prakash GKS. Selective Late‐Stage Hydrodefluorination of Trifluoromethylarenes: A Facile Access to Difluoromethylarenes. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700396] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Socrates B. Munoz
- Loker Hydrocarbon Research Institute and Department of Chemistry University of Southern California University Park 90089‐1661 Los Angeles CA USA
| | - Chuanfa Ni
- Key Laboratory of Organofluorine Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences 345 Ling‐Ling Road 200032 Shanghai China
| | - Zhe Zhang
- Loker Hydrocarbon Research Institute and Department of Chemistry University of Southern California University Park 90089‐1661 Los Angeles CA USA
| | - Fang Wang
- Loker Hydrocarbon Research Institute and Department of Chemistry University of Southern California University Park 90089‐1661 Los Angeles CA USA
| | - Nan Shao
- Loker Hydrocarbon Research Institute and Department of Chemistry University of Southern California University Park 90089‐1661 Los Angeles CA USA
| | - Thomas Mathew
- Loker Hydrocarbon Research Institute and Department of Chemistry University of Southern California University Park 90089‐1661 Los Angeles CA USA
| | - George A. Olah
- Loker Hydrocarbon Research Institute and Department of Chemistry University of Southern California University Park 90089‐1661 Los Angeles CA USA
| | - G. K. Surya Prakash
- Loker Hydrocarbon Research Institute and Department of Chemistry University of Southern California University Park 90089‐1661 Los Angeles CA USA
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18
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Pike SD, Crimmin MR, Chaplin AB. Organometallic chemistry using partially fluorinated benzenes. Chem Commun (Camb) 2017; 53:3615-3633. [DOI: 10.1039/c6cc09575e] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fluorobenzenes, in particular fluorobenzene (FB) and 1,2-difluorobenzene (1,2-DiFB), are versatile solvents for conducting organometallic chemistry and transition-metal-based catalysis.
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Affiliation(s)
| | - Mark R. Crimmin
- Department of Chemistry
- Imperial College London
- London SW7 2AZ
- UK
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19
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Krahl T, Kemnitz E. Aluminium fluoride – the strongest solid Lewis acid: structure and reactivity. Catal Sci Technol 2017. [DOI: 10.1039/c6cy02369j] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Highly Lewis acidic aluminium fluorides are interesting heterogeneous catalysts for many reactions, especially C–H and C–F bonds can be activated at room temperature.
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Affiliation(s)
- Thoralf Krahl
- Humboldt-Universität zu Berlin
- D-12489 Berlin
- Germany
- Nanofluor GmbH
- D-12489 Berlin
| | - Erhard Kemnitz
- Humboldt-Universität zu Berlin
- D-12489 Berlin
- Germany
- Nanofluor GmbH
- D-12489 Berlin
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20
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Goh KKK, Sinha A, Fraser C, Young RD. Catalytic halodefluorination of aliphatic carbon–fluorine bonds. RSC Adv 2016. [DOI: 10.1039/c6ra09429e] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A variety of halosilanes, in conjunction with aluminum catalysts, convert fluorocarbons into higher halocarbons.
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Affiliation(s)
- Kelvin K. K. Goh
- Department of Chemistry
- National University of Singapore
- Singapore
| | - Arup Sinha
- Department of Chemistry
- National University of Singapore
- Singapore
| | - Craig Fraser
- Department of Chemistry
- National University of Singapore
- Singapore
| | - Rowan D. Young
- Department of Chemistry
- National University of Singapore
- Singapore
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21
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Ahrens T, Teltewskoi M, Ahrens M, Braun T, Laubenstein R. Competing reaction pathways of 3,3,3-trifluoropropene at rhodium hydrido, silyl and germyl complexes: C–F bond activation versus hydrogermylation. Dalton Trans 2016; 45:17495-17507. [DOI: 10.1039/c6dt03027k] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reactivity of the Rh complexes [Rh(L)(PEt3)3] (L = H, Si(OEt)3, GePh3) towards CH2CHCF3 was investigated which involve C–F bond activation and germylation reactions.
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Affiliation(s)
- Theresia Ahrens
- Humboldt-Universität zu Berlin
- Department of Chemistry
- D-12489 Berlin
- Germany
| | - Michael Teltewskoi
- Humboldt-Universität zu Berlin
- Department of Chemistry
- D-12489 Berlin
- Germany
| | - Mike Ahrens
- Humboldt-Universität zu Berlin
- Department of Chemistry
- D-12489 Berlin
- Germany
| | - Thomas Braun
- Humboldt-Universität zu Berlin
- Department of Chemistry
- D-12489 Berlin
- Germany
| | - Reik Laubenstein
- Humboldt-Universität zu Berlin
- Department of Chemistry
- D-12489 Berlin
- Germany
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22
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Yamada T, Saito K, Akiyama T. Transformation of Trifluorotoluenes Triggered by Titanium(IV) Chloride-Catalyzed Hydrodefluorination using Hydrosilanes. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201500920] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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23
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Đorđević N, Tay MQY, Muthaiah S, Ganguly R, Dimić D, Vidović D. C–F Bond Activation by Transient Phosphenium Dications. Inorg Chem 2015; 54:4180-2. [DOI: 10.1021/ic5031125] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nemanja Đorđević
- SPMS-CBC, Nanyang Technological University, 21 Nanyang Link, Singapore 638737, Singapore
| | - Madelyn Qin Yi Tay
- SPMS-CBC, Nanyang Technological University, 21 Nanyang Link, Singapore 638737, Singapore
| | | | - Rakesh Ganguly
- SPMS-CBC, Nanyang Technological University, 21 Nanyang Link, Singapore 638737, Singapore
| | - Dušan Dimić
- Faculty of Physical Chemistry, University of Belgrade, 11000 Belgrade, Republic of Serbia
| | - Dragoslav Vidović
- SPMS-CBC, Nanyang Technological University, 21 Nanyang Link, Singapore 638737, Singapore
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24
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Lanzinger D, Höhlein IM, Weiß SB, Rieger B. Catalytic C–F activation via cationic group IV metallocenes. J Organomet Chem 2015. [DOI: 10.1016/j.jorganchem.2014.12.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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25
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Abstract
Nanoscale metal fluorides and hydroxide fluorides prepared according the fluorolytic sol–gel synthesis represent a powerful class of bi-acidic heterogeneous catalysts.
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Affiliation(s)
- Erhard Kemnitz
- Department für Chemie
- Humboldt-Universität zu Berlin
- D-12489 Berlin
- Germany
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26
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Ahrens T, Kohlmann J, Ahrens M, Braun T. Functionalization of fluorinated molecules by transition-metal-mediated C-F bond activation to access fluorinated building blocks. Chem Rev 2014; 115:931-72. [PMID: 25347593 DOI: 10.1021/cr500257c] [Citation(s) in RCA: 609] [Impact Index Per Article: 60.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Theresia Ahrens
- Humboldt-Universität zu Berlin , Department of Chemistry, Brook-Taylor-Straße 2, 12489 Berlin, Germany
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27
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Schwartsburd L, Mahon MF, Poulten RC, Warren MR, Whittlesey MK. Mechanistic Studies of the Rhodium NHC Catalyzed Hydrodefluorination of Polyfluorotoluenes. Organometallics 2014. [DOI: 10.1021/om500827d] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Leonid Schwartsburd
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2
7AY, U.K
| | - Mary F. Mahon
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2
7AY, U.K
| | - Rebecca C. Poulten
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2
7AY, U.K
| | - Mark R. Warren
- Station I19, Diamond Lightsource Ltd., Harwell Science
and Innovation Campus, Didcot OX11 ODE, U.K
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28
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Gianetti TL, Bergman RG, Arnold J. Carbon–fluorine bond cleavage in fluoroarenes via a niobium(iii) imido complex: from stoichiometric to catalytic hydrodefluorination. Chem Sci 2014. [DOI: 10.1039/c4sc00006d] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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29
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Affiliation(s)
- Timo Stahl
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
| | - Hendrik F. T. Klare
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
| | - Martin Oestreich
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
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30
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Baumgartner R, Stieger GK, McNeill K. Complete hydrodehalogenation of polyfluorinated and other polyhalogenated benzenes under mild catalytic conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:6545-6553. [PMID: 23663092 DOI: 10.1021/es401183v] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Polyfluorinated arenes are increasingly used in industry and can be considered emerging contaminants. Environmentally applicable degradation methods leading to full defluorination are not reported in the literature. In this study, it is demonstrated that the heterogeneous catalyst Rh/Al2O3 is capable of fully defluorinating and hydrogenating polyfluorinated benzenes in water under mild conditions (1 atm H2, ambient temperature) with degradation half-lives between 11 and 42 min. Analysis of the degradation rates of the 12 fluorobenzene congeners showed two trends: slower degradation with increasing number of fluorine substituents and increasing degradation rates with increasing number of adjacent fluorine substituents. The observed fluorinated intermediates indicated that adjacent fluorine substituents are preferably removed. Besides defluorination and hydrogenation, the scope of the catalyst includes dehalogenation of polychlorinated benzenes, bromobenzene, iodobenzene, and selected mixed dihalobenzenes. Polychlorobenzene degradation rates, like their fluorinated counterparts, decreased with increasing halogen substitution. In contrast to the polyfluorobenzenes though, removal of chlorine substituents was sterically driven. All monohalobenzenes were degraded at similar rates; however, when two carbon-halogen bonds were in direct intramolecular competition, the weaker bond was broken first. Differences in sorption affinities of the substrates are suggested to play a major role in determining the relative rates of transformation of halobenzenes by Rh/Al2O3 and H2.
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Affiliation(s)
- Rebekka Baumgartner
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zurich, Switzerland
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31
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Ahrens M, Scholz G, Braun T, Kemnitz E. Catalytic Hydrodefluorination of Fluoromethanes at Room Temperature by Silylium-ion-like Surface Species. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201300608] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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32
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Ahrens M, Scholz G, Braun T, Kemnitz E. Catalytic Hydrodefluorination of Fluoromethanes at Room Temperature by Silylium-ion-like Surface Species. Angew Chem Int Ed Engl 2013; 52:5328-32. [DOI: 10.1002/anie.201300608] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 02/22/2013] [Indexed: 11/08/2022]
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33
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Preiss UP, Steinfeld G, Scherer H, Erle AMT, Benkmil B, Kraft A, Krossing I. Fluorinated Weakly Coordinating Anions [M(hfip)6]-(M = Nb, Ta): Syntheses, Structural Characterizations and Computations. Z Anorg Allg Chem 2013. [DOI: 10.1002/zaac.201300027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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34
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Kuehnel MF, Lentz D, Braun T. Synthesis of Fluorinated Building Blocks by Transition-Metal-Mediated Hydrodefluorination Reactions. Angew Chem Int Ed Engl 2013; 52:3328-48. [DOI: 10.1002/anie.201205260] [Citation(s) in RCA: 313] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Indexed: 11/06/2022]
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35
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Kuehnel MF, Lentz D, Braun T. Synthese fluorierter Bausteine durch Übergangsmetall-vermittelte Hydrodefluorierungsreaktionen. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201205260] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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36
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Stahl T, Klare HFT, Oestreich M. C(sp3)-F bond activation of CF3-substituted anilines with catalytically generated silicon cations: spectroscopic evidence for a hydride-bridged Ru-S dimer in the catalytic cycle. J Am Chem Soc 2013; 135:1248-51. [PMID: 23311960 DOI: 10.1021/ja311398j] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Heterolytic splitting of the Si-H bond mediated by a Ru-S bond forms a sulfur-stabilized silicon cation that is sufficiently electrophilic to abstract fluoride from CF(3) groups attached to selected anilines. The ability of the Ru-H complex, generated in the cooperative activation step, to intramolecularly transfer its hydride to the intermediate carbenium ion (stabilized in the form of a cationic thioether complex) is markedly dependent on the electronic nature of its phosphine ligand. An electron-deficient phosphine thwarts the reduction step but, based on the Ru-S catalyst, half of an equivalent of an added alkoxide not only facilitates but also accelerates the catalysis. The intriguing effect is rationalized by the formation of a hydride-bridged Ru-S dimer that was detected by (1)H NMR spectroscopy. A refined catalytic cycle is proposed.
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Affiliation(s)
- Timo Stahl
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
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37
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Yow S, Gates SJ, White AJP, Crimmin MR. Zirconocene Dichloride Catalyzed Hydrodefluorination of C sp 2F bonds. Angew Chem Int Ed Engl 2012; 51:12559-63. [DOI: 10.1002/anie.201207036] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 09/24/2012] [Indexed: 11/12/2022]
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38
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Yow S, Gates SJ, White AJP, Crimmin MR. Zirconocene Dichloride Catalyzed Hydrodefluorination of C sp 2F bonds. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201207036] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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39
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Baumgartner R, McNeill K. Hydrodefluorination and hydrogenation of fluorobenzene under mild aqueous conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:10199-10205. [PMID: 22871102 DOI: 10.1021/es302188f] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Fluorinated organic compounds are increasingly used in many applications, and their release to the environment is expected. It is therefore important to find suitable methods for degradation of fluorinated compounds under environmentally relevant conditions. In this study, a simple heterogeneous rhodium-based catalytic system (Rh/Al(2)O(3) and H(2)) for hydrodefluorination and hydrogenation of fluorobenzene under mild aqueous conditions (1 atm of H(2), ambient temperature) was developed and the underlying reaction mechanism was investigated. Fluorobenzene degraded rapidly (t(1/2) ≈ 0.2 h) to form cyclohexane and fluoride (F(-)) as the stable end products, with benzene and cyclohexene observed as intermediates. Cyclohexadiene intermediates were not observed but were expected to form during the hydrogenation of benzene. Three postulated but unobserved fluorinated intermediates were subjected to the catalytic reaction conditions, and it was concluded that they most likely do not form during the fluorobenzene degradation reaction. Isotope labeling experiments showed that the unsaturated intermediates undergo rapid and reversible hydrogenation/dehydrogenation under the reaction conditions and also that fully saturated compounds are unreactive in the catalytic system. Both molecular hydrogen and water were sources of hydrogen in the final cyclohexane product. Kinetic fitting indicated that sorption/desorption of fluorobenzene onto the catalyst surface plays an important role in the mechanism.
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Affiliation(s)
- Rebekka Baumgartner
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zurich, Switzerland
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40
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Kuehnel MF, Holstein P, Kliche M, Krüger J, Matthies S, Nitsch D, Schutt J, Sparenberg M, Lentz D. Titanium-Catalyzed Vinylic and Allylic CF Bond Activation-Scope, Limitations and Mechanistic Insight. Chemistry 2012; 18:10701-14. [DOI: 10.1002/chem.201201125] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Indexed: 11/09/2022]
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41
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Zhao W, Wu J, Cao S. Highly Efficient Nickel(II) Chloride/Bis(tricyclohexylphosphine)nickel(II) Chloride-Cocatalyzed Hydrodefluorination of Fluoroarenes and Trifluorotoluenes with Superhydride. Adv Synth Catal 2012. [DOI: 10.1002/adsc.201100783] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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42
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Fluorierung von closo,closo-[B21H18]- mit aHF und F2 zu closo,closo-[B21H18-xFx]- (x = 1-3) und closo,closo-[B21F18]-. Z Anorg Allg Chem 2012. [DOI: 10.1002/zaac.201100395] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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43
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Kuehnel MF, Schlöder T, Riedel S, Nieto-Ortega B, Ramírez FJ, López Navarrete JT, Casado J, Lentz D. Synthesis of the Smallest Axially Chiral Molecule by Asymmetric Carbon-Fluorine Bond Activation. Angew Chem Int Ed Engl 2012; 51:2218-20. [DOI: 10.1002/anie.201108105] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Indexed: 11/07/2022]
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44
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Kuehnel MF, Schlöder T, Riedel S, Nieto-Ortega B, Ramírez FJ, López Navarrete JT, Casado J, Lentz D. Synthese des kleinsten axial-chiralen Moleküls durch asymmetrische Kohlenstoff-Fluor-Bindungsaktivierung. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201108105] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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45
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Dugan TR, Goldberg JM, Brennessel WW, Holland PL. Low-Coordinate Cobalt Fluoride Complexes: Synthesis, Reactions, and Production from C–F Activation Reactions. Organometallics 2012. [DOI: 10.1021/om200991k] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Thomas R. Dugan
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Jonathan M. Goldberg
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - William W. Brennessel
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Patrick L. Holland
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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46
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Breyer D, Braun T, Kläring P. Synthesis and Reactivity of the Fluoro Complex trans-[Pd(F)(4-C5NF4)(iPr2PCH2CH2OCH3)2]: C–F Bond Formation and Catalytic C–F Bond Activation Reactions. Organometallics 2012. [DOI: 10.1021/om200998d] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David Breyer
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin,
Germany
| | - Thomas Braun
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin,
Germany
| | - Paul Kläring
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin,
Germany
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47
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Caputo CB, Stephan DW. Activation of Alkyl C–F Bonds by B(C6F5)3: Stoichiometric and Catalytic Transformations. Organometallics 2011. [DOI: 10.1021/om200885c] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christopher B. Caputo
- Department of Chemistry, University of Toronto, 80 St. George
Street, Toronto, Ontario, Canada M5S 3H6
| | - Douglas W. Stephan
- Department of Chemistry, University of Toronto, 80 St. George
Street, Toronto, Ontario, Canada M5S 3H6
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48
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Keyes L, Sun AD, Love JA. Exploration of the Scope of Pt-Catalyzed C-F Activation. European J Org Chem 2011. [DOI: 10.1002/ejoc.201100478] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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49
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Kethe A, Tracy AF, Klumpp DA. Protolytic defluorination of trifluoromethyl-substituted arenes. Org Biomol Chem 2011; 9:4545-9. [PMID: 21547324 DOI: 10.1039/c0ob01276a] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of trifluoromethyl-substituted arenes were studied in their reactions with Brønsted superacids. The products from these reactions suggest the formation of reactive electrophiles, such as carbocations, acylium cations or equivalent electrophilic species. As such, Friedel-Crafts-type reactions occur between these species and arene nucleophiles. NMR studies were done, and the results suggest the formation of an acyl group from the trifluoromethyl groups in the superacid.
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Affiliation(s)
- Anila Kethe
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, USA
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50
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Klis T, Powell DR, Wojtas L, Wehmschulte RJ. Synthesis and Characterization of Bulky Cationic Arylalkylaluminum Compounds. Organometallics 2011. [DOI: 10.1021/om200120y] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tomasz Klis
- Department of Chemistry, Florida Institute of Technology, 150 West University Boulevard, Melbourne, Florida 32901, United States
| | - Douglas R. Powell
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019-5251, United States
| | - Lukasz Wojtas
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States
| | - Rudolf J. Wehmschulte
- Department of Chemistry, Florida Institute of Technology, 150 West University Boulevard, Melbourne, Florida 32901, United States
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