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Bauri S, Ramachandran A, Rit A. (Benz)imidazo[1,2-a]quinolinium Salts: Access via Unprecedented Regiospecific non-AAIPEX Strategy and Study of Their Tunable Properties. Chemistry 2024; 30:e202303744. [PMID: 38226763 DOI: 10.1002/chem.202303744] [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: 11/10/2023] [Revised: 12/21/2023] [Accepted: 01/09/2024] [Indexed: 01/17/2024]
Abstract
An unprecedented non-AAIPEX protocol has been developed to access diverse monosubstituted cationic polycyclic heteroaromatic compounds (cPHACs) from the readily available azolium salts and phenacyl bromides via Ru(II)-catalyzed tandem annulation cum aromatization. This atom-economic protocol executes a range of intermediate steps e. g. double C-H activation, nucleophilic addition, annulation, and dehydration cum aromatization in one-pot manner under the generation of H2O as the sole byproduct. Moreover, the systematic tunability of photo-physical and electrochemical properties of these new class of cPHACs can be authenticated from the DFT calculated frontier molecular orbital energies that might be beneficial for their potential applications in optoelectronics and DNA intercalation.
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Affiliation(s)
- Somnath Bauri
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Arya Ramachandran
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Arnab Rit
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India
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2
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Bormann N, Ward JS, Bergmann AK, Wenz P, Rissanen K, Gong Y, Hatz WB, Burbaum A, Mulks FF. Diiminium Nucleophile Adducts Are Stable and Convenient Strong Lewis Acids. Chemistry 2023; 29:e202302089. [PMID: 37427889 DOI: 10.1002/chem.202302089] [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: 07/05/2023] [Revised: 07/08/2023] [Accepted: 07/10/2023] [Indexed: 07/11/2023]
Abstract
Strong Lewis acids are essential tools for manifold chemical procedures, but their scalable deployment is limited by their costs and safety concerns. We report a scalable, convenient, and inexpensive synthesis of stable diiminium-based reagents with a Lewis acidic carbon centre. Coordination with pyridine donors stabilises these centres; the 2,2'-bipyridine adduct shows a chelation effect at carbon. Due to high fluoride, hydride, and oxide affinities, the diiminium pyridine adducts are promising soft and hard Lewis acids. They effectively produce acylpyridinium salts from carboxylates that can acylate amines to give amides and imides even from electronically intractable coupling partners.
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Affiliation(s)
- Niklas Bormann
- Institute for Organic Chemistry (iOC), RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Jas S Ward
- Department of Chemistry, University of Jyvaskyla, P. O. Box. 35, Survontie 9 B, 40014, Jyväskylä, Finland
| | - Ann Kathrin Bergmann
- Institute for Organic Chemistry (iOC), RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Paula Wenz
- Department of Chemistry, University of Jyvaskyla, P. O. Box. 35, Survontie 9 B, 40014, Jyväskylä, Finland
| | - Kari Rissanen
- Department of Chemistry, University of Jyvaskyla, P. O. Box. 35, Survontie 9 B, 40014, Jyväskylä, Finland
| | - Yiwei Gong
- Institute for Organic Chemistry (iOC), RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Wolf-Benedikt Hatz
- Institute for Organic Chemistry (iOC), RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Alexander Burbaum
- Institute for Organic Chemistry (iOC), RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Florian F Mulks
- Institute for Organic Chemistry (iOC), RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
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3
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Yoshida S. C-F Transformations of Benzotrifluorides by the Activation of Ortho-Hydrosilyl Group. CHEM REC 2023; 23:e202200308. [PMID: 36762730 DOI: 10.1002/tcr.202200308] [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: 12/28/2022] [Revised: 01/23/2023] [Indexed: 02/11/2023]
Abstract
Single C-F transformations of aromatic trifluoromethyl compounds are challenging issues due to the strong C-F bond. We have recently developed selective methods for single C-F transformations such as allylation of o-hydrosilyl-substituted benzotrifluorides through the hydride abstraction with trityl cations. Single C-F thiolation and azidation of o-(hydrosilyl)benzotrifluorides were achieved using trityl sulfides and trityl azide catalyzed by Yb(OTf)3 . Treatment of o-(hydrosilyl)benzotrifluorides with trityl chloride resulted in single C-F chlorination. The resulting fluorosilyl group served in further transformations including protonation, halogenation, and Hiyama cross-coupling with C-Si cleavage. We also synthesized benzyl fluorides by LiAlH4 -reduction of the resulting fluorosilanes and further C-F transformations. These methods enabled us to prepare a broad range of organofluorines from simple benzotrifluorides through C-F and C-Si transformations.
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Affiliation(s)
- Suguru Yoshida
- Department of Biological Science and Technology, Faculty of Advanced Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan
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Mondal S, Stevanovic B, Butler E, Wang JW, Meanwell MW. Electrochemical C-F bond activation of trifluoromethylarenes using silylium ions. Chem Commun (Camb) 2023; 59:6694-6697. [PMID: 37183480 DOI: 10.1039/d3cc01850d] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We report a mild, electrochemical trihydrodefluorination (e-THDF) for breaking highly stable C-F bonds in trifluoromethyl arenes to form the corresponding methyl arene products. Uniquely, this "green" approach relies on the in situ generation of Lewis acidic silyl cations that mediate fluoride abstraction. Overall, e-THDF has significantly improved functional group tolerance over current methods and should inspire the continued development of defluorinative processes.
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Affiliation(s)
- Subhojit Mondal
- Department of Chemistry, University of Alberta, Edmonton, Canada.
| | - Boris Stevanovic
- Department of Chemistry, University of Alberta, Edmonton, Canada.
| | - Eric Butler
- Department of Chemistry, University of Alberta, Edmonton, Canada.
| | - Jason W Wang
- Department of Chemistry, University of Alberta, Edmonton, Canada.
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5
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Köring L, Stepen A, Birenheide B, Barth S, Leskov M, Schoch R, Krämer F, Breher F, Paradies J. Boron-Centered Lewis Superacid through Redox-Active Ligands: Application in C-F and S-F Bond Activation. Angew Chem Int Ed Engl 2023; 62:e202216959. [PMID: 36621900 DOI: 10.1002/anie.202216959] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 01/04/2023] [Accepted: 01/04/2023] [Indexed: 01/10/2023]
Abstract
A series of redox-responsive ferrocenyl-substituted boranes and boronic esters were synthesized. Oxidation of the ferrocenyl ligand to the ferrocenium resulted in a drastic increase in the Lewis acidity beyond the strength of SbF5 , which was investigated experimentally and computationally. The resulting highly Lewis acidic boron compounds were used for catalytic C-F and S-F bond activation.
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Affiliation(s)
- Laura Köring
- Department of Chemistry, Paderborn University, Warburger Strasse 100, 33098, Paderborn, Germany
| | - Arne Stepen
- Department of Chemistry, Paderborn University, Warburger Strasse 100, 33098, Paderborn, Germany
| | - Bernhard Birenheide
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131, Karlsruhe, Germany
| | - Simon Barth
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131, Karlsruhe, Germany
| | - Maxim Leskov
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131, Karlsruhe, Germany
| | - Roland Schoch
- Department of Chemistry, Paderborn University, Warburger Strasse 100, 33098, Paderborn, Germany
| | - Felix Krämer
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131, Karlsruhe, Germany
| | - Frank Breher
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131, Karlsruhe, Germany
| | - Jan Paradies
- Department of Chemistry, Paderborn University, Warburger Strasse 100, 33098, Paderborn, Germany
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6
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Shen ZJ, Zhu C, Zhang X, Yang C, Rueping M, Guo L, Xia W. Organoboron Reagent-Controlled Selective (Deutero)Hydrodefluorination. Angew Chem Int Ed Engl 2023; 62:e202217244. [PMID: 36525004 DOI: 10.1002/anie.202217244] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 12/23/2022]
Abstract
(Deuterium-labeled) CF2 H- and CFH2 -moieties are of high interest in drug discovery. The high demand for the incorporation of these fluoroalkyl moieties into molecular structures has witnessed significant synthetic progress, particularly in the (deutero)hydrodefluorination of CF3 -containing compounds. However, the controllable replacement of fluorine atoms while maintaining high chemoselectivity remains challenging. Herein, we describe the development of a selective (deutero)hydrodefluorination reaction via electrolysis. The reaction exhibits a remarkable chemoselectivity control, which is enabled by the addition of different organoboron sources. The procedure is operationally simple and scalable, and provides access in one step to high-value building blocks for application in medicinal chemistry. Furthermore, density functional theory (DFT) calculations have been carried out to investigate the reaction mechanism and to rationalize the chemoselectivity observed.
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Affiliation(s)
- Zheng-Jia Shen
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China
| | - Chen Zhu
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Xiao Zhang
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China
| | - Chao Yang
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China
| | - Magnus Rueping
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Lin Guo
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China
| | - Wujiong Xia
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China.,School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, 453007, China
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7
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Antoni PW, Golz C, Hansmann MM. Organic Four-Electron Redox Systems Based on Bipyridine and Phenanthroline Carbene Architectures. Angew Chem Int Ed Engl 2022; 61:e202203064. [PMID: 35298870 PMCID: PMC9325510 DOI: 10.1002/anie.202203064] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Indexed: 12/14/2022]
Abstract
Novel organic redox systems that display multistage redox behaviour are highly sought-after for a series of applications such as organic batteries or electrochromic materials. Here we describe a simple strategy to transfer well-known two-electron redox active bipyridine and phenanthroline architectures into novel strongly reducing four-electron redox systems featuring fully reversible redox events with up to five stable oxidation states. We give spectroscopic and structural insight into the changes involved in the redox-events and present characterization data on all isolated oxidation states. The redox-systems feature strong UV/Vis/NIR polyelectrochromic properties such as distinct strong NIR absorptions in the mixed valence states. Two-electron charge-discharge cycling studies indicate high electrochemical stability at strongly negative potentials, rendering the new redox architectures promising lead structures for multi-electron anolyte materials.
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Affiliation(s)
- Patrick W Antoni
- Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str.6, 44227, Dortmund, Germany
| | - Christopher Golz
- Georg-August Universität Göttingen, Institut für Organische und Biomolekulare Chemie, Tammannstr. 2, 37077, Göttingen, Germany
| | - Max M Hansmann
- Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str.6, 44227, Dortmund, Germany
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Antoni PW, Golz C, Hansmann MM. Organic Four‐Electron Redox Systems Based on Bipyridine and Phenanthroline Carbene Architectures. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202203064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Patrick W. Antoni
- TU Dortmund: Technische Universitat Dortmund Fakultät für Chemie und Chemische Biologie GERMANY
| | - Christopher Golz
- Georg-August-Universität Göttingen: Georg-August-Universitat Gottingen Institut für Organische und Biomolekulare Chemie GERMANY
| | - Max M. Hansmann
- TU Dortmund: Technische Universitat Dortmund Fakultät für Chemie und Chemische Biologie Otto-Hahn Str.6 44227 Dortmund GERMANY
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9
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Barthélemy A, Glootz K, Scherer H, Hanske A, Krossing I. Ga +-catalyzed hydrosilylation? About the surprising system Ga +/HSiR 3/olefin, proof of oxidation with subvalent Ga + and silylium catalysis with perfluoroalkoxyaluminate anions. Chem Sci 2022; 13:439-453. [PMID: 35126976 PMCID: PMC8729802 DOI: 10.1039/d1sc05331k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 11/21/2021] [Indexed: 12/19/2022] Open
Abstract
Already 1 mol% of subvalent [Ga(PhF)2]+[pf]- ([pf]- = [Al(ORF)4]-, RF = C(CF3)3) initiates the hydrosilylation of olefinic double bonds under mild conditions. Reactions with HSiMe3 and HSiEt3 as substrates efficiently yield anti-Markovnikov and anti-addition products, while bulkier substrates such as HSiiPr3 are less reactive. Investigating the underlying mechanism by gas chromatography and STEM analysis, we unexpectedly found that H2 and metallic Ga0 formed. Without the addition of olefins, the formation of R3Si-F-Al(ORF)3 (R = alkyl), a typical degradation product of the [pf]- anion in the presence of a small silylium ion, was observed. Electrochemical analysis revealed a surprisingly high oxidation potential of univalent [Ga(PhF)2]+[pf]- in weakly coordinating, but polar ortho-difluorobenzene of E 1/2(Ga+/Ga0; oDFB) = +0.26-0.37 V vs. Fc+/Fc (depending on the scan rate). Apparently, subvalent Ga+, mainly known as a reductant, initially oxidizes the silane and generates a highly electrophilic, silane-supported, silylium ion representing the actual catalyst. Consequently, the [Ga(PhF)2]+[pf]-/HSiEt3 system also hydrodefluorinates C(sp3)-F bonds in 1-fluoroadamantane, 1-fluorobutane and PhCF3 at room temperature. In addition, both catalytic reactions may be initiated using only 0.2 mol% of [Ph3C]+[pf]- as a silylium ion-generating initiator. These results indicate that silylium ion catalysis is possible with the straightforward accessible weakly coordinating [pf]- anion. Apparently, the kinetics of hydrosilylation and hydrodefluorination are faster than that of anion degradation under ambient conditions. These findings open up new windows for main group catalysis.
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Affiliation(s)
- Antoine Barthélemy
- Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg Albertstr. 21 79104 Freiburg Germany
| | - Kim Glootz
- Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg Albertstr. 21 79104 Freiburg Germany
| | - Harald Scherer
- Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg Albertstr. 21 79104 Freiburg Germany
| | - Annaleah Hanske
- Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg Albertstr. 21 79104 Freiburg Germany
| | - Ingo Krossing
- Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF), Universität Freiburg Albertstr. 21 79104 Freiburg Germany
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Idogawa R, Kobayashi A, Kim Y, Shimomori K, Hosoya T, Yoshida S. Hydride reduction of o-(fluorosilyl)benzodifluorides for subsequent C–F transformations. Chem Commun (Camb) 2022; 58:3521-3524. [DOI: 10.1039/d1cc06761c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An efficient method for sequential C–F transformations of o-hydrosilyl-substituted benzotrifluorides is disclosed. A key to the success is hydride reduction of o-fluorosilyl-substituted difluoromethylenes prepared by a single C–F transformation of...
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