1
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Hoque IU, Samanta A, Pramanik S, Chowdhury SR, Lo R, Maity S. Photocascade chemoselective controlling of ambident thio(seleno)cyanates with alkenes via catalyst modulation. Nat Commun 2024; 15:5739. [PMID: 38982050 PMCID: PMC11233607 DOI: 10.1038/s41467-024-49279-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 05/28/2024] [Indexed: 07/11/2024] Open
Abstract
Controlling the ambident reactivity of thiocyanates in reaction manifolds has been a long-standing and formidable challenge. We report herein a photoredox strategy for installing thiocyanates and isothiocyanates in a controlled chemoselective fashion by manipulating the ambident-SCN through catalyst modulation. The methodology allows redox-, and pot-economical 'on-demand' direct access to both hydrothiophene and pyrrolidine heterocycles from the same feedstock alkenes and bifunctional thiocyanomalonates in a photocascade sequence. Its excellent chemoselectivity profile was further expanded to access Se- and N-heterocycles by harnessing selenonitriles. Redox capability of the catalysts, which dictates the substrates to participate in a single or cascade catalytic cycle, was proposed as the key to the present chemodivergency of this process. In addition, detailed mechanistic insights are provided by a conjugation of extensive control experiments and dispersion-corrected density functional theory (DFT) calculations.
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Affiliation(s)
- Injamam Ul Hoque
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (Indian School of Mines), Dhanbad, JH, 826004, India
| | - Apurba Samanta
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (Indian School of Mines), Dhanbad, JH, 826004, India
| | - Shyamal Pramanik
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (Indian School of Mines), Dhanbad, JH, 826004, India
| | - Soumyadeep Roy Chowdhury
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (Indian School of Mines), Dhanbad, JH, 826004, India
| | - Rabindranath Lo
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo námĕstí 542/2, Prague, 160 000, Czech Republic
| | - Soumitra Maity
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (Indian School of Mines), Dhanbad, JH, 826004, India.
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2
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Vega-Fernández J, Marcos V, Álvarez J, Capitán MJ, Fraile A, Alemán J. Photocatalytic functionalization of thin-layer membranes using a monomer truncation strategy. NANOSCALE ADVANCES 2024; 6:3181-3187. [PMID: 38868836 PMCID: PMC11166120 DOI: 10.1039/d4na00149d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 04/24/2024] [Indexed: 06/14/2024]
Abstract
We present the design and synthesis of two new organic polymer films making use of a liquid-liquid interfacial amine-acid chloride polymerization strategy. One of them was additionally functionalized in situ by the anchoring of N-phenyl-phenothiazine through a monomer truncation strategy, which endowed it with photocatalytic activity. This photoactive film displays interesting luminescence phenomena that were used for the oxidation of a variety of sulphides to their corresponding sulfoxides and reduction of aryl bromines.
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Affiliation(s)
- Jorge Vega-Fernández
- Departamento de Química Orgánica (Módulo 1), Facultad de Ciencias, Universidad Autónoma de Madrid 28049-Madrid Spain https://josealemanlara.wixsite.com/froncat
| | - Vanesa Marcos
- Departamento de Química Orgánica (Módulo 1), Facultad de Ciencias, Universidad Autónoma de Madrid 28049-Madrid Spain https://josealemanlara.wixsite.com/froncat
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid 28049-Madrid Spain
| | - Jesús Álvarez
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid 29049-Madrid Spain
- Instituto de Ciencia de Materiales "Nicolás Cabrera", Univ. Autónoma de Madrid 28049-Madrid Spain
- Instituto de Física de la Materia Condensada IFIMAC, Univ. Autónoma de Madrid 28049-Madrid Spain
- Física de Sistemas Crecidos con Baja Dimensionalidad, Universidad Autónoma de Madrid, Unidad Asociada al CSIC por el IEM DP Madrid Spain
| | - María José Capitán
- Instituto de Estructura de la Materia IEM-CSIC 28006-Madrid Spain
- Física de Sistemas Crecidos con Baja Dimensionalidad, Universidad Autónoma de Madrid, Unidad Asociada al CSIC por el IEM DP Madrid Spain
| | - Alberto Fraile
- Departamento de Química Orgánica (Módulo 1), Facultad de Ciencias, Universidad Autónoma de Madrid 28049-Madrid Spain https://josealemanlara.wixsite.com/froncat
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid 28049-Madrid Spain
| | - José Alemán
- Departamento de Química Orgánica (Módulo 1), Facultad de Ciencias, Universidad Autónoma de Madrid 28049-Madrid Spain https://josealemanlara.wixsite.com/froncat
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid 28049-Madrid Spain
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3
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Mentzel P, Holzapfel M, Schmiedel A, Günther J, Michel M, Krummenacher I, Wodyński A, Kaupp M, Braunschweig H, Lambert C. Structure and Photophysics of N-Tolanyl-phenochalcogenazines and their Radical Cations. Chemistry 2024; 30:e202303782. [PMID: 38293898 DOI: 10.1002/chem.202303782] [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: 11/14/2023] [Revised: 01/16/2024] [Accepted: 01/26/2024] [Indexed: 02/01/2024]
Abstract
The study focuses on the structural and photophysical characteristics of neutral and oxidized forms of N-tolanyl-phenochalcogenazines PZX-tolan with X=O, S, Se, and Te. X-ray crystal structure analyses show a pseudo-equatorial (pe) structure of the tolan substituent in the O, S, and Se dyads, while the Te dyad possesses a pseudo-axial (pa) structure. DFT calculations suggest the pe structure for O and S, and the pa structure for Se and Te as stable forms. Steady-state and femtosecond-time resolved optical spectroscopy in toluene solution indicate that the O and S dyads emit from a CT state, whereas the Se and Te dyads emit from a tolan-localized state. The T1 state is tolan-localized in all cases, showing phosphorescence at 77 K. The heavy atom effect of chalcogens induces intersystem crossing from S1 to Tx, resulting in a decreasing S1 lifetime from 2.1 ns to 0.42 ps. The T1 states possess potential for singlet oxygen sensitization with a high quantum yield (ca. 40 %) for the O, S, and Se dyads. Radical cations exhibit spin density primarily localized at the heterocycle. EPR measurements and quasirelativistic DFT calculations reveal a very strong g-tensor anisotropy, supporting the pe structure for the S and Se derivatives.
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Affiliation(s)
- Paul Mentzel
- Institut für Organische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Marco Holzapfel
- Institut für Organische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Alexander Schmiedel
- Institut für Organische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Johanna Günther
- Institut für Organische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Maximilian Michel
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ivo Krummenacher
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Artur Wodyński
- Technische Universität Berlin, Institut für Chemie, Theoretische Chemie/Quantenchemie, Sekr. C7, Strasse des 17. Juni 135, 10623, Berlin, Germany
| | - Martin Kaupp
- Technische Universität Berlin, Institut für Chemie, Theoretische Chemie/Quantenchemie, Sekr. C7, Strasse des 17. Juni 135, 10623, Berlin, Germany
| | - Holger Braunschweig
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Christoph Lambert
- Institut für Organische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Center for Nanosystems Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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4
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Zhang B, Li TT, Mao ZC, Jiang M, Zhang Z, Zhao K, Qu WY, Xiao WJ, Chen JR. Enantioselective Cyanofunctionalization of Aromatic Alkenes via Radical Anions. J Am Chem Soc 2024; 146:1410-1422. [PMID: 38179949 DOI: 10.1021/jacs.3c10439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
Alkene radical ions constitute an integral and unique class of reactive intermediates for the synthesis of valuable compounds because they have both unpaired spins and charge. However, relatively few synthetic applications of alkene radical anions have emerged due to a dearth of generally applicable and mild radical anion generation approaches. Precise control over the chemo- and stereoselectivity in alkene radical anion-mediated processes represents another long-standing challenge due to their high reactivity. To overcome these issues, here, we develop a new redox-neutral strategy that seamlessly merges photoredox and copper catalysis to enable the controlled generation of alkene radical anions and their orthogonal enantioselective cyanofunctionalization via distonic-like species. This new strategy enables highly regio-, chemo-, and enantioselective hydrocyanation, deuterocyanation, and cyanocarboxylation of alkenes without stoichiometric reductants or oxidants under visible light irradiation. This protocol provides a new blueprint for the exploration of the transformation potential of alkene radical anions.
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Affiliation(s)
- Bin Zhang
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China
| | - Tian-Tian Li
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China
| | - Zhi-Cheng Mao
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China
| | - Min Jiang
- College of Materials, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, China
| | - Zhihan Zhang
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China
| | - Ke Zhao
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China
| | - Wen-Yuan Qu
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China
| | - Wen-Jing Xiao
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China
- Wuhan Institute of Photochemistry and Technology, 7 North Bingang Road, Wuhan, Hubei 430082, China
| | - Jia-Rong Chen
- College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China
- Wuhan Institute of Photochemistry and Technology, 7 North Bingang Road, Wuhan, Hubei 430082, China
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5
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Tian X, Liu Y, Yakubov S, Schütte J, Chiba S, Barham JP. Photo- and electro-chemical strategies for the activations of strong chemical bonds. Chem Soc Rev 2024; 53:263-316. [PMID: 38059728 DOI: 10.1039/d2cs00581f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
The employment of light and/or electricity - alternatively to conventional thermal energy - unlocks new reactivity paradigms as tools for chemical substrate activations. This leads to the development of new synthetic reactions and a vast expansion of chemical spaces. This review summarizes recent developments in photo- and/or electrochemical activation strategies for the functionalization of strong bonds - particularly carbon-heteroatom (C-X) bonds - via: (1) direct photoexcitation by high energy UV light; (2) activation via photoredox catalysis under irradiation with relatively lower energy UVA or blue light; (3) electrochemical reduction; (4) combination of photocatalysis and electrochemistry. Based on the types of the targeted C-X bonds, various transformations ranging from hydrodefunctionalization to cross-coupling are covered with detailed discussions of their reaction mechanisms.
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Affiliation(s)
- Xianhai Tian
- Fakultät für Chemie und Pharmazie, Universität Regensburg, 93040 Regensburg, Germany.
| | - Yuliang Liu
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637371, Singapore.
| | - Shahboz Yakubov
- Fakultät für Chemie und Pharmazie, Universität Regensburg, 93040 Regensburg, Germany.
| | - Jonathan Schütte
- Fakultät für Chemie und Pharmazie, Universität Regensburg, 93040 Regensburg, Germany.
| | - Shunsuke Chiba
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637371, Singapore.
| | - Joshua P Barham
- Fakultät für Chemie und Pharmazie, Universität Regensburg, 93040 Regensburg, Germany.
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6
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Weick F, Hagmeyer N, Giraud M, Dietzek-Ivanšić B, Wagenknecht HA. Reductive Activation of Aryl Chlorides by Tuning the Radical Cation Properties of N-Phenylphenothiazines as Organophotoredox Catalysts. Chemistry 2023; 29:e202302347. [PMID: 37589486 DOI: 10.1002/chem.202302347] [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: 07/24/2023] [Revised: 08/17/2023] [Accepted: 08/17/2023] [Indexed: 08/18/2023]
Abstract
Aryl chlorides as substrates for arylations present a particular challenge for photoredox catalytic activation due to their strong C(sp2 )-Cl bond and their strong reduction potential. Electron-rich N-phenylphenothiazines, as organophotoredox catalysts, are capable of cleaving aryl chlorides simply by photoinduced electron transfer without the need for an additional electrochemical activation setup or any other advanced photocatalysis technique. Due to the extremely strong reduction potential in the excited state of the N-phenylphenothiazines the substrate scope is high and includes aryl chlorides both with electron-withdrawing and electron-donating substituents. We evidence this reactivity for photocatalytic borylations and phosphonylations. Advanced time-resolved transient absorption spectroscopy in combination with electrochemistry was the key to elucidating and comparing the unusual photophysical properties not only of the N-phenylphenothiazines, but also of their cation radicals as the central intermediates in the photocatalytic cycle. The revealed photophysics allowed the excited-state and radical-cation properties to be fine-tuned by the molecular design of the N-phenylphenothiazines; this improved the photocatalytic activity.
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Affiliation(s)
- Fabian Weick
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
| | - Nina Hagmeyer
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Lessingstraße 4, 07743, Jena, Germany
| | - Madeleine Giraud
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
| | - Benjamin Dietzek-Ivanšić
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Lessingstraße 4, 07743, Jena, Germany
- Research Department Functional Interfaces, Leibniz Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745, Jena, Germany
| | - Hans-Achim Wagenknecht
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
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7
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Halder S, Mandal S, Kundu A, Mandal B, Adhikari D. Super-Reducing Behavior of Benzo[ b]phenothiazine Anion Under Visible-Light Photoredox Condition. J Am Chem Soc 2023; 145:22403-22412. [PMID: 37788971 DOI: 10.1021/jacs.3c05787] [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
Herein we describe the anion of benzo[b]phenothiazine as a super reductant species upon excitation by visible light. In contrary to N-substituted phenothiazines or benzophenothiazines, this molecule holds extreme reducing power to promote single electron transfer-based reductive cleavage at a potential of -3.51 V vs SCE. As a proof, a plethora of aryl chloride substrates have been reductively cleaved to fabricate molecules of the class isoindolinone and oxindole. Moreover, an aryl-chloride bond has been homolytically cleaved to generate aryl radicals that have been utilized for C-C cross-coupling or C-P bond formation reactions. To prove its extreme reducing ability, some of the aryl fluoride bonds have been cleaved to generate aryl radicals. A detailed photophysical study including steady-state and time-resolved spectroscopic techniques explain the molecule's behavior upon light excitation, and that correlates with its reactivity pattern. Theoretical calculations disclose the benzophenothiazine anion to be slightly puckered at the ground state as the molecule is antiaromatic in nature. In contrast, the excited-state geometry is planar, which is also close to that of the intermediate after one electron transfer. Abating the antiaromaticity of the anionic species is partially responsible for its highly reducing behavior.
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Affiliation(s)
- Supriya Halder
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar 140306, India
| | - Sourav Mandal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar 140306, India
| | - Abhishek Kundu
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar 140306, India
| | - Baishanal Mandal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar 140306, India
| | - Debashis Adhikari
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar 140306, India
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8
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Wang R, Gao L, Zhou C, Zhang X. Haloperfluoroalkylation of Unactivated Terminal Alkenes over Phenylphenothiazine-Based Porous Organic Polymers. CHINESE J ORG CHEM 2023. [DOI: 10.6023/cjoc202211013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2023]
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9
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Noto N, Saito S. Arylamines as More Strongly Reducing Organic Photoredox Catalysts than fac-[Ir(ppy) 3]. ACS Catal 2022. [DOI: 10.1021/acscatal.2c05034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- Naoki Noto
- Integrated Research Consortium on Chemical Sciences (IRCCS), Nagoya University, Chikusa, Nagoya, Aichi 464-8602, Japan
| | - Susumu Saito
- Integrated Research Consortium on Chemical Sciences (IRCCS), Nagoya University, Chikusa, Nagoya, Aichi 464-8602, Japan
- Graduate School of Science, Nagoya University, Chikusa, Nagoya, Aichi 464-8602, Japan
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10
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Welsh EN, Robertson KN, Speed AWH. Gram-Scale Synthesis of the N-Phenyl Phenothiazine Photocatalyst by Benzyne Addition. CAN J CHEM 2022. [DOI: 10.1139/cjc-2022-0139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
N-phenyl phenothiazine is one of the most reducing photoredox catalysts. Its synthesis commonly requires transition metal catalyzed cross-coupling reactions. Here we show the syntheses of four aryl phenothiazines via a benzyne route, including a multi-gram scale synthesis of N-phenyl phenothiazine. While yields are modest, the simplicity, low cost, and lack of requirement for cross-coupling catalysts in this synthesis will be attractive to users of this photocatalyst.
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Affiliation(s)
- Erin N. Welsh
- Dalhousie University, 3688, Department of Chemistry, Halifax, Canada
| | | | - Alexander W. H. Speed
- Dalhousie University, Chemistry Department, 6274 Coburg Road, Box 15000, Halifax, Nova Scotia, Canada,
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11
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Shennan BDA, Berheci D, Crompton JL, Davidson TA, Field JL, Williams BA, Dixon DJ. Branching out: redox strategies towards the synthesis of acyclic α-tertiary ethers. Chem Soc Rev 2022; 51:5878-5929. [PMID: 35770619 DOI: 10.1039/d1cs00669j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Acyclic α-tertiary ethers represent a highly prevalent functionality, common to high-value bioactive molecules, such as pharmaceuticals and natural products, and feature as crucial synthetic handles in their construction. As such their synthesis has become an ever-more important goal in synthetic chemistry as the drawbacks of traditional strong base- and acid-mediated etherifications have become more limiting. In recent years, the generation of highly reactive intermediates via redox approaches has facilitated the synthesis of highly sterically-encumbered ethers and accordingly these strategies have been widely applied in α-tertiary ether synthesis. This review summarises and appraises the state-of-the-art in the application of redox strategies enabling acyclic α-tertiary ether synthesis.
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Affiliation(s)
- Benjamin D A Shennan
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Diana Berheci
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Jessica L Crompton
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Timothy A Davidson
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Joshua L Field
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Benedict A Williams
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Darren J Dixon
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
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12
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Widness JK, Enny DG, McFarlane-Connelly KS, Miedenbauer MT, Krauss TD, Weix DJ. CdS Quantum Dots as Potent Photoreductants for Organic Chemistry Enabled by Auger Processes. J Am Chem Soc 2022; 144:12229-12246. [PMID: 35772053 DOI: 10.1021/jacs.2c03235] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Strong reducing agents (<-2.0 V vs saturated calomel electrode (SCE)) enable a wide array of useful organic chemistry, but suffer from a variety of limitations. Stoichiometric metallic reductants such as alkali metals and SmI2 are commonly employed for these reactions; however, considerations including expense, ease of use, safety, and waste generation limit the practicality of these methods. Recent approaches utilizing energy from multiple photons or electron-primed photoredox catalysis have accessed reduction potentials equivalent to Li0 and shown how this enables selective transformations of aryl chlorides via aryl radicals. However, in some cases, low stability of catalytic intermediates can limit turnover numbers. Herein, we report the ability of CdS nanocrystal quantum dots (QDs) to function as strong photoreductants and present evidence that a highly reducing electron is generated from two consecutive photoexcitations of CdS QDs with intermediate reductive quenching. Mechanistic experiments suggest that Auger recombination, a photophysical phenomenon known to occur in photoexcited anionic QDs, generates transient thermally excited electrons to enable the observed reductions. Using blue light-emitting diodes (LEDs) and sacrificial amine reductants, aryl chlorides and phosphate esters with reduction potentials up to -3.4 V vs SCE are photoreductively cleaved to afford hydrodefunctionalized or functionalized products. In contrast to small-molecule catalysts, QDs are stable under these conditions and turnover numbers up to 47 500 have been achieved. These conditions can also effect other challenging reductions, such as tosylate protecting group removal from amines, debenzylation of benzyl-protected alcohols, and reductive ring opening of cyclopropane carboxylic acid derivatives.
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Affiliation(s)
- Jonas K Widness
- Department of Chemistry, UW─Madison, Madison, Wisconsin 53706, United States
| | - Daniel G Enny
- Department of Chemistry, UW─Madison, Madison, Wisconsin 53706, United States
| | | | - Mahilet T Miedenbauer
- Materials Science Program, University of Rochester, Rochester, New York 14627, United States
| | - Todd D Krauss
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States.,Materials Science Program, University of Rochester, Rochester, New York 14627, United States.,Institute of Optics, University of Rochester, Rochester, New York 14627, United States
| | - Daniel J Weix
- Department of Chemistry, UW─Madison, Madison, Wisconsin 53706, United States
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13
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Kodo T, Nagao K, Ohmiya H. Organophotoredox-catalyzed semipinacol rearrangement via radical-polar crossover. Nat Commun 2022; 13:2684. [PMID: 35562383 PMCID: PMC9106707 DOI: 10.1038/s41467-022-30395-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 04/29/2022] [Indexed: 01/10/2023] Open
Abstract
Over the past century, significant progress in semipinacol rearrangement involving 1,2-migration of α-hydroxy carbocations has been made in the areas of catalysis and total synthesis of natural products. To access the α-hydroxy carbocation intermediate, conventional acid-mediated or electrochemical approaches have been employed. However, the photochemical semipinacol rearrangement has been underdeveloped. Herein, we report the organophotoredox-catalyzed semipinacol rearrangement via radical-polar crossover (RPC). A phenothiazine-based organophotoredox catalyst facilitates the generation of an α-hydroxy non-benzylic alkyl radical followed by oxidation to the corresponding carbocation, which can be exploited to undergo the semipinacol rearrangement. As a result, the photochemical approach enables decarboxylative semipinacol rearrangement of β-hydroxycarboxylic acid derivatives and alkylative semipinacol type rearrangement of allyl alcohols with carbon electrophiles, producing α-quaternary or α-tertiary carbonyls bearing sp3-rich scaffolds.
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Affiliation(s)
- Taiga Kodo
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Kazunori Nagao
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan.
| | - Hirohisa Ohmiya
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan.
- JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
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14
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Nakagawa M, Matsuki Y, Nagao K, Ohmiya H. A Triple Photoredox/Cobalt/Brønsted Acid Catalysis Enabling Markovnikov Hydroalkoxylation of Unactivated Alkenes. J Am Chem Soc 2022; 144:7953-7959. [PMID: 35476545 DOI: 10.1021/jacs.2c00527] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We demonstrate Markovnikov hydroalkoxylation of unactivated alkenes using alcohols through a triple catalysis consisting of photoredox, cobalt, and Brønsted acid catalysts under visible light irradiation. The triple catalysis realizes three key elementary steps in a single catalytic cycle: (1) Co(III) hydride generation by photochemical reduction of Co(II) followed by protonation, (2) metal hydride hydrogen atom transfer (MHAT) of alkenes by Co(III) hydride, and (3) oxidation of the alkyl Co(III) complex to alkyl Co(IV). The precise control of protons and electrons by the three catalysts allows the elimination of strong acids and external reductants/oxidants that are required in the conventional methods.
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Affiliation(s)
- Masanari Nakagawa
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Yuki Matsuki
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Kazunori Nagao
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Hirohisa Ohmiya
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.,JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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15
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Xia W, Zhou ZA, Lv J, Xiang SH, Wang YB, Tan B. Facile synthesis of N-aryl phenothiazines and phenoxazines via Brønsted acid catalyzed C-H amination of arenes. Chem Commun (Camb) 2022; 58:1613-1616. [PMID: 35019918 DOI: 10.1039/d1cc06730c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
N-Aryl phenothiazines and phenoxazines are of significant importance in various disciplines throughout academia and industry. The conventional synthetic strategy for the construction of these structures centers on the transition-metal-catalyzed cross-coupling of aryl halides with phenothiazines or phenoxazines. Here we present an organocatalytic approach to access N-naphthyl phenothiazine and phenoxazine scaffolds through a straightforward C-H amination of arenes as enabled by an azo group. This reaction features operational simplicity, adequate substrate generality and excellent functional group compatibility. Notably, the efficiency of the catalyst could be perfectly preserved after 5 catalytic cycles.
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Affiliation(s)
- Wang Xia
- Shenzhen Grubbs Institute, Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Zi-An Zhou
- Shenzhen Grubbs Institute, Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Jie Lv
- Shenzhen Grubbs Institute, Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Shao-Hua Xiang
- Shenzhen Grubbs Institute, Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China. .,Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yong-Bin Wang
- Shenzhen Grubbs Institute, Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Bin Tan
- Shenzhen Grubbs Institute, Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China.
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16
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Li H, Wenger OS. Photophysics of Perylene Diimide Dianions and Their Application in Photoredox Catalysis. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202110491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Han Li
- Department of Chemistry University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
| | - Oliver S. Wenger
- Department of Chemistry University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
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17
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Zhou J, Mao L, Wu MX, Peng Z, Yang Y, Zhou M, Zhao XL, Shi X, Yang HB. Extended phenothiazines: synthesis, photophysical and redox properties, and efficient photocatalytic oxidative coupling of amines. Chem Sci 2022; 13:5252-5260. [PMID: 35655566 PMCID: PMC9093200 DOI: 10.1039/d2sc01086k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/08/2022] [Indexed: 11/21/2022] Open
Abstract
Herein, we successfully developed a ring-fusion approach to extend the conjugation length of phenothiazines that were demonstrated to be efficient photocatalysts for visible-light-driven oxidative coupling reactions of amines under an air atmosphere.
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Affiliation(s)
- Jun Zhou
- School of Chemistry and Molecular Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, 3663 N, Zhongshan Road, Shanghai 200062, P. R. China
| | - Lijun Mao
- School of Chemistry and Molecular Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, 3663 N, Zhongshan Road, Shanghai 200062, P. R. China
| | - Meng-Xiang Wu
- School of Chemistry and Molecular Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, 3663 N, Zhongshan Road, Shanghai 200062, P. R. China
| | - Zhiyong Peng
- School of Chemistry and Molecular Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, 3663 N, Zhongshan Road, Shanghai 200062, P. R. China
| | - Yiming Yang
- School of Chemistry and Molecular Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, 3663 N, Zhongshan Road, Shanghai 200062, P. R. China
| | - Manfei Zhou
- School of Chemistry and Molecular Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, 3663 N, Zhongshan Road, Shanghai 200062, P. R. China
| | - Xiao-Li Zhao
- School of Chemistry and Molecular Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, 3663 N, Zhongshan Road, Shanghai 200062, P. R. China
| | - Xueliang Shi
- School of Chemistry and Molecular Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, 3663 N, Zhongshan Road, Shanghai 200062, P. R. China
| | - Hai-Bo Yang
- School of Chemistry and Molecular Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, 3663 N, Zhongshan Road, Shanghai 200062, P. R. China
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18
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Sack D, Wagenknecht H. The Concept of Photozymes: Short Peptides with Photoredox Catalytic Activity for Nucleophilic Additions to α‐Phenyl Styrenes. European J Org Chem 2021. [DOI: 10.1002/ejoc.202101068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Daniel Sack
- Institute of Organic Chemistry Karlsruhe Institute of Technology (KIT) Fritz-Haber-Weg 16 76131 Karlsruhe Germany
| | - Hans‐Achim Wagenknecht
- Institute of Organic Chemistry Karlsruhe Institute of Technology (KIT) Fritz-Haber-Weg 16 76131 Karlsruhe Germany
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19
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Li H, Wenger OS. Photophysics of Perylene Diimide Dianions and Their Application in Photoredox Catalysis. Angew Chem Int Ed Engl 2021; 61:e202110491. [PMID: 34787359 PMCID: PMC9299816 DOI: 10.1002/anie.202110491] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 10/16/2021] [Indexed: 12/25/2022]
Abstract
The two‐electron reduced forms of perylene diimides (PDIs) are luminescent closed‐shell species whose photochemical properties seem underexplored. Our proof‐of‐concept study demonstrates that straightforward (single) excitation of PDI dianions with green photons provides an excited state that is similarly or more reducing than the much shorter‐lived excited states of PDI radical monoanions, which are typically accessible after biphotonic excitation with blue photons. Thermodynamically demanding photocatalytic reductive dehalogenations and reductive C−O bond cleavage reactions of lignin model compounds have been performed using sodium dithionite acts as a reductant, either in aqueous solution or in biphasic water–acetonitrile mixtures in the presence of a phase transfer reagent. Our work illustrates the concept of multi‐electron reduction of a photocatalyst by a sacrificial reagent prior to irradiation with low‐energy photons as a means of generating very reactive excited states.
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Affiliation(s)
- Han Li
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Oliver S Wenger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
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20
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Nagao K, Ohmiya H. Carbocation Generation by Organophotoredox Catalysis. J SYN ORG CHEM JPN 2021. [DOI: 10.5059/yukigoseikyokaishi.79.1005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Kazunori Nagao
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University
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21
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Schmidt M, Esser B. Cavity-promotion by pillar[5]arenes expedites organic photoredox-catalysed reductive dehalogenations. Chem Commun (Camb) 2021; 57:9582-9585. [PMID: 34546245 DOI: 10.1039/d1cc03221f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The efficiency of the photo-induced electron transfer in photoredox catalysis is limited by the diffusional collision of the excited catalyst and the substrate. We herein present cavity-bound photoredox catalysts, which preassociate the substrates, leading to significantly shortened reaction times. A pillar[5]arene serves as the cavity and phenothiazine as a catalyst in the reductive dehalogenation of aliphatic bromides as a proof of concept reaction.
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Affiliation(s)
- Maximilian Schmidt
- Institute for Organic Chemistry, University of Freiburg, Albertstraße 21, 79104 Freiburg, Germany.
| | - Birgit Esser
- Institute for Organic Chemistry, University of Freiburg, Albertstraße 21, 79104 Freiburg, Germany. .,Freiburg Materials Research Center, University of Freiburg, Stefan-Meier-Str. 21, 79104 Freiburg, Germany.,Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
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22
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Reiß B, Hu Q, Riedle E, Wagenknecht H. The Dependence of Chemical Quantum Yields of Visible Light Photoredox Catalysis on the Irradiation Power. CHEMPHOTOCHEM 2021. [DOI: 10.1002/cptc.202100090] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Barbara Reiß
- Institute of Organic Chemistry Karlsruhe Institute of Technology (KIT) Fritz-Haber-Weg 6 76131 Karlsruhe Germany
| | - Qi Hu
- Lehrstuhl für BioMolekulare Optik Ludwig-Maximilians-Universität (LMU) Oettingenstraße 67 80538 München Germany
| | - Eberhard Riedle
- Lehrstuhl für BioMolekulare Optik Ludwig-Maximilians-Universität (LMU) Oettingenstraße 67 80538 München Germany
| | - Hans‐Achim Wagenknecht
- Institute of Organic Chemistry Karlsruhe Institute of Technology (KIT) Fritz-Haber-Weg 6 76131 Karlsruhe Germany
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23
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Nakagawa M, Nagao K, Ikeda Z, Reynolds M, Ibáñez I, Wang J, Tokunaga N, Sasaki Y, Ohmiya H. Organophotoredox‐Catalyzed Decarboxylative N‐Alkylation of Sulfonamides. ChemCatChem 2021. [DOI: 10.1002/cctc.202100803] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Masanari Nakagawa
- Division of Pharmaceutical Sciences Graduate School of Medical Sciences Kanazawa University Kakuma-machi, Kanazawa 920-1192 Japan
| | - Kazunori Nagao
- Division of Pharmaceutical Sciences Graduate School of Medical Sciences Kanazawa University Kakuma-machi, Kanazawa 920-1192 Japan
| | - Zenichi Ikeda
- Research Takeda Pharmaceutical Company Limited Fujisawa, Kanagawa 251-8555 Japan
| | - Matthew Reynolds
- Research Takeda Pharmaceutical Company Limited Fujisawa, Kanagawa 251-8555 Japan
| | - Ignacio Ibáñez
- Research Takeda Pharmaceutical Company Limited Fujisawa, Kanagawa 251-8555 Japan
| | - Junsi Wang
- Research Takeda Pharmaceutical Company Limited Fujisawa, Kanagawa 251-8555 Japan
| | - Norihito Tokunaga
- Research Takeda Pharmaceutical Company Limited Fujisawa, Kanagawa 251-8555 Japan
| | - Yusuke Sasaki
- Research Takeda Pharmaceutical Company Limited Fujisawa, Kanagawa 251-8555 Japan
| | - Hirohisa Ohmiya
- Division of Pharmaceutical Sciences Graduate School of Medical Sciences Kanazawa University Kakuma-machi, Kanazawa 920-1192 Japan
- JST PRESTO Kawaguchi, Saitama 332-0012 Japan
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24
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Bell JD, Murphy JA. Recent advances in visible light-activated radical coupling reactions triggered by (i) ruthenium, (ii) iridium and (iii) organic photoredox agents. Chem Soc Rev 2021; 50:9540-9685. [PMID: 34309610 DOI: 10.1039/d1cs00311a] [Citation(s) in RCA: 134] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Photoredox chemistry with organic or transition metal agents has been reviewed in earlier years, but such is the pace of progress that we will overlap very little with earlier comprehensive reviews. This review first presents an overview of the area of research and then examines recent examples of C-C, C-N, C-O and C-S bond formations via radical intermediates with transition metal and organic radical promoters. Recent successes with Birch reductions are also included. The transition metal chemistry will be restricted to photocatalysts based on the most widely used metals, Ru and Ir, but includes coupling chemistries that take advantage of low-valent nickel, or occasionally copper, complexes to process the radicals that are formed. Our focus is on developments in the past 10 years (2011-2021). This period has also seen great advances in the chemistry of organic photoredox reagents and the review covers this area. The review is intended to present highlights and is not comprehensive.
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Affiliation(s)
- Jonathan D Bell
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
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25
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Kobayashi R, Shibutani S, Nagao K, Ikeda Z, Wang J, Ibáñez I, Reynolds M, Sasaki Y, Ohmiya H. Decarboxylative N-Alkylation of Azoles through Visible-Light-Mediated Organophotoredox Catalysis. Org Lett 2021; 23:5415-5419. [PMID: 34139122 DOI: 10.1021/acs.orglett.1c01745] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
An organophotoredox-catalyzed decarboxylative cross-coupling between azole nucleophiles and aliphatic carboxylic acid-derived redox-active esters is demonstrated. This protocol efficiently installs various tertiary or secondary alkyl fragments onto the nitrogen atom of azole nucleophiles under mild and transition-metal-free conditions. The pyridinium additive successfully inhibits the formation of elimination byproducts from the carbocation intermediate. This reaction is applicable to the synthesis of a protein-degrader-like molecule containing an azole and a thalidomide.
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Affiliation(s)
- Rino Kobayashi
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Shotaro Shibutani
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Kazunori Nagao
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Zenichi Ikeda
- Research, Takeda Pharmaceutical Company Limited, 2-26-1 Muraoka-Higashi, Fujisawa, Kanagawa 251-8555, Japan
| | - Junsi Wang
- Research, Takeda Pharmaceutical Company Limited, 2-26-1 Muraoka-Higashi, Fujisawa, Kanagawa 251-8555, Japan
| | - Ignacio Ibáñez
- Research, Takeda Pharmaceutical Company Limited, 2-26-1 Muraoka-Higashi, Fujisawa, Kanagawa 251-8555, Japan
| | - Matthew Reynolds
- Research, Takeda Pharmaceutical Company Limited, 2-26-1 Muraoka-Higashi, Fujisawa, Kanagawa 251-8555, Japan
| | - Yusuke Sasaki
- Research, Takeda Pharmaceutical Company Limited, 2-26-1 Muraoka-Higashi, Fujisawa, Kanagawa 251-8555, Japan
| | - Hirohisa Ohmiya
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.,JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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26
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Mayer L, Müller TJJ. 3,10‐Diaryl Phenothiazines – One‐pot Synthesis and Conformational Tuning of Ground and Excited State Electronics. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Laura Mayer
- Institut für Organische Chemie und Makromolekulare Chemie Heinrich-Heine-Universität Düsseldorf Universitätsstrasse 1 40225 Düsseldorf Germany
| | - Thomas J. J. Müller
- Institut für Organische Chemie und Makromolekulare Chemie Heinrich-Heine-Universität Düsseldorf Universitätsstrasse 1 40225 Düsseldorf Germany
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27
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Rombach D, Birenheide B, Wagenknecht H. Photoredox Catalytic Pentafluorosulfanylative Domino Cyclization of α-Substituted Alkenes to Oxaheterocycles by Using SF 6. Chemistry 2021; 27:8088-8093. [PMID: 33831262 PMCID: PMC8252034 DOI: 10.1002/chem.202100767] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Indexed: 01/14/2023]
Abstract
Virtually inert sulfur hexafluoride becomes a precious pentafluorosulfanylation agent, if properly activated by photoredox catalysis, to access α-fluoro and α-alkoxy SF5 -compounds. This advanced protocol converts SF6 in the presence of alkynols as bifunctional C-C- and C-O-bond forming reagents directly into pentafluorosulfanylated oxygen-containing heterocycles in a single step from α-substituted alkenes. The proposed mechanism is supported by theoretical calculations and gives insights not only in the pentafluorosulfanylation step but also into formation of the carbon-carbon bond and is in full agreement with Baldwin's cyclization rules. The key step is a radical type 5-, 6- respectively 7-exo-dig-cyclization. The synthesized oxaheterocycles cannot be simply prepared by other synthetic methods, show a high level of structural complexity and significantly expand the scope of pentafluorosulfanylated building blocks valuable for medicinal and material chemistry.
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Affiliation(s)
- David Rombach
- Laboratory of Inorganic ChemistrySwiss Federal Institute of Technology (ETH)Vladimir-Prelog-Weg 1–5/108093ZürichSwitzerland
| | - Bernhard Birenheide
- Institute of Inorganic ChemistryKalsruhe Institute of Technology (KIT)Engesserstr. 1576131KarlsruheGermany
| | - Hans‐Achim Wagenknecht
- Institute of Organic ChemistryKarlsruhe Institute of Technology (KIT)Fritz-Haber-Weg 676131KarlsruheGermany
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28
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Swisher NA, Corbin DA, Miyake GM. Synthesis, Characterization, and Reactivity of N-Alkyl Phenoxazines in Organocatalyzed Atom Transfer Radical Polymerization. ACS Macro Lett 2021; 10:453-459. [PMID: 34306819 DOI: 10.1021/acsmacrolett.1c00055] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Core-modified N-alkyl phenoxazines were synthesized and evaluated as photoredox catalysts (PCs) in organocatalyzed atom transfer radical polymerization (O-ATRP). Each PC was characterized and found to strongly absorb UVA and visible light, undergo reversible oxidation to radical cation species, and exhibit high quantum yields of fluorescence (Φf > 77%). PCs found to exhibit intramolecular charge transfer in their excited state were capable of the controlled synthesis of poly(methyl methacrylate) with good molecular weight control (I* ~ 100%) and moderately low dispersity (Đ < 1.30).
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Affiliation(s)
- Nicholas A. Swisher
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Daniel A. Corbin
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Garret M. Miyake
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
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29
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Abstract
We report the photosubstitution of one cyano group in dicyanobenzene-based photocatalysts and thermally activated delayed fluorescence (TADF) emitters. The reaction is a general degradation pathway for some widely used organic photocatalysts such as 4CzIPN and suggests that the active photocatalyst in many reactions is likely different from 4CzIPN. On the contrary, photosubstitution is a facile route to diverse highly reducing photocatalysts and blue TADF emitters.
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Affiliation(s)
- Sascha Grotjahn
- Faculty of Chemistry and Pharmacy, University of Regensburg, Universitaetsstrasse 31, 93053 Regensburg, Germany
| | - Burkhard König
- Faculty of Chemistry and Pharmacy, University of Regensburg, Universitaetsstrasse 31, 93053 Regensburg, Germany
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30
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Wagenknecht HA, Seyfert F. N-Arylbenzo[b]phenothiazines as Reducing Photoredox Catalysts for Nucleophilic Additions of Alcohols to Styrenes: Shift towards Visible Light. Synlett 2021. [DOI: 10.1055/a-1304-4575] [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
Abstract
N-Phenylphenothiazines are an important class of photoredox catalysts because they are synthetically well accessible, they allow the tuning of the optoelectronic properties by different substituents, and they have strong reduction properties for activation of alkenes. One of the major disadvantages of N-phenylphenothiazines, however, is the excitation at 365 nm in the UV-A light range. We synthesized three differently dialkylamino-substituted N-phenylbenzo[b]phenothiazines as alternative photoredox catalysts and applied them for the nucleophilic addition of alkohols to α-methyl styrene. The additional benzene ring shift the absorbance bathochromically and allows performing the photocatalyses by excitation at 385 nm and 405 nm. This type of photoredox catalysis tolerates other functional groups, as representatively shown for alcohols as substrates with C–C and C–N triple bonds.
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31
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Schmalzbauer M, Marcon M, König B. Excited State Anions in Organic Transformations. Angew Chem Int Ed Engl 2021; 60:6270-6292. [PMID: 33002265 PMCID: PMC7986118 DOI: 10.1002/anie.202009288] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/17/2020] [Indexed: 02/06/2023]
Abstract
Utilizing light is a smart way to fuel chemical transformations as it allows the energy to be selectively focused on certain molecules. Many reactions involving electronically excited species proceed via open-shell intermediates, which offer novel and unique routes to expand the hitherto used synthetic toolbox in organic chemistry. The direct conversion of non-prefunctionalized, less activated compounds is a highly desirable goal to pave the way towards more sustainable and atom-economic chemical processes. Photoexcited closed-shell anions have been shown to reach extreme potentials in single electron transfer reactions and reveal unusual excited-state reactivity. It is, therefore, surprising that their use as a reagent or photocatalyst is limited to a few examples. In this Review, we briefly discuss the characteristics of anionic photochemistry, highlight pioneering work, and show recent progress which has been made by utilizing photoexcited anionic species in organic synthesis.
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Affiliation(s)
- Matthias Schmalzbauer
- Faculty of Chemistry and PharmacyUniversity of RegensburgUniversitätsstrasse 3193053RegensburgGermany
| | - Michela Marcon
- Faculty of Chemistry and PharmacyUniversity of RegensburgUniversitätsstrasse 3193053RegensburgGermany
| | - Burkhard König
- Faculty of Chemistry and PharmacyUniversity of RegensburgUniversitätsstrasse 3193053RegensburgGermany
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32
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Nucleophilic Aromatic Substitution of Polyfluoroarene to Access Highly Functionalized 10-Phenylphenothiazine Derivatives. Molecules 2021; 26:molecules26051365. [PMID: 33806360 PMCID: PMC7962002 DOI: 10.3390/molecules26051365] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 11/29/2022] Open
Abstract
Nucleophilic aromatic substitution (SNAr) reactions can provide metal-free access to synthesize monosubstituted aromatic compounds. We developed efficient SNAr conditions for p-selective substitution of polyfluoroarenes with phenothiazine in the presence of a mild base to afford the corresponding 10-phenylphenothiazine (PTH) derivatives. The resulting polyfluoroarene-bearing PTH derivatives were subjected to a second SNAr reaction to generate highly functionalized PTH derivatives with potential applicability as photocatalysts for the reduction of carbon–halogen bonds.
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33
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Seyfert F, Mitha M, Wagenknecht H. Nucleophilic Alkoxylations of Unactivated Alkyl Olefins and α‐Methyl Styrene by Photoredox Catalysis. European J Org Chem 2021. [DOI: 10.1002/ejoc.202001533] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Fabienne Seyfert
- Institute of Organic Chemistry Karlsruhe Institute of Technology (KIT) Fritz-Haber-Weg 6 76131 Karlsruhe Germany
| | - Mathis Mitha
- Institute of Organic Chemistry Karlsruhe Institute of Technology (KIT) Fritz-Haber-Weg 6 76131 Karlsruhe Germany
| | - Hans‐Achim Wagenknecht
- Institute of Organic Chemistry Karlsruhe Institute of Technology (KIT) Fritz-Haber-Weg 6 76131 Karlsruhe Germany
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Donabauer K, König B. Strategies for the Photocatalytic Generation of Carbanion Equivalents for Reductant-Free C-C Bond Formations. Acc Chem Res 2021; 54:242-252. [PMID: 33325678 PMCID: PMC7871440 DOI: 10.1021/acs.accounts.0c00620] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Indexed: 12/18/2022]
Abstract
ConspectusThe use of photocatalysis in organic chemistry has encountered a surge of novel transformations since the start of the 21st century. The majority of these transformations are driven by the generation and subsequent reaction of radicals, owing to the intrinsic property of common photocatalysts to transfer single electrons from their excited state. While this is a powerful and elegant method to develop novel transformations, several research groups recently sought to further extend the toolbox of photocatalysis into the realm of polar ionic reactivity by the formation of cationic as well as anionic key reaction intermediates to furnish a desired product.Our group became especially interested in the photocatalytic formation of anionic carbon nucleophiles, as the overall transformation resembles classical organometallic reactions like Grignard, Barbier, and Reformatsky reactions, which are ubiquitous in organic synthesis with broad applications especially in the formation of valuable C-C bonds. Although these classical reactions are frequently applied, their use still bears certain disadvantages; one is the necessity of an (over)stoichiometric amount of a reducing metal. The reducing, low-valent, metal is solely applied to activate the starting material to form the organometallic carbanion synthon, while the final reaction product does generally not contain a metal species. Hence, a stoichiometric amount of metal salt is bound to be generated at the end of each reaction, diminishing the atom economy. The use of visible light as mild and traceless activation agent to drive chemical reactions can be a means to arrive at a more atom economic transformation, as a reducing metal source is avoided. Beyond this, the vast pool of photocatalytic activation methods offers the potential to employ easily available starting materials, as simple as unfunctionalized alkanes, to open novel and more facile retrosynthetic pathways. However, as mentioned above, photocatalysis is dominated by open-shell radical reactivity. With neutral radicals showing an intrinsically different reactivity than ionic species, novel strategies to form intermediates expressing a polar behavior need to be developed in order to achieve this goal.In the last couple of years, several methods toward this aim have been reported by our group and others. This Account aims to give an overview of the different existing strategies to photocatalytically form carbon centered anions or equivalents of those in order to form C-C bonds. As the main concept is to omit a stoichiometric reductant source (like a low-valent metal in classical organometallic reactions), only redox-neutral and reductant-free transformations were taken into closer consideration. We present selected examples of important strategies and try to illustrate the intentions and concepts behind the methods developed by our group and others.
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Affiliation(s)
- Karsten Donabauer
- Institute for Organic Chemistry, University of
Regensburg, Universitätsstraße 31, 93053 Regensburg,
Germany
| | - Burkhard König
- Institute for Organic Chemistry, University of
Regensburg, Universitätsstraße 31, 93053 Regensburg,
Germany
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35
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Schmalzbauer M, Marcon M, König B. Photoangeregte Anionen in organischen Reaktionen. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009288] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Matthias Schmalzbauer
- Fakultät für Chemie und Pharmazie Universität Regensburg Universitätsstraße 31 93053 Regensburg Deutschland
| | - Michela Marcon
- Fakultät für Chemie und Pharmazie Universität Regensburg Universitätsstraße 31 93053 Regensburg Deutschland
| | - Burkhard König
- Fakultät für Chemie und Pharmazie Universität Regensburg Universitätsstraße 31 93053 Regensburg Deutschland
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36
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Glaser F, Larsen CB, Kerzig C, Wenger OS. Aryl dechlorination and defluorination with an organic super-photoreductant. Photochem Photobiol Sci 2020; 19:1035-1041. [PMID: 32588869 DOI: 10.1039/d0pp00127a] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Direct excitation of the commercially available super-electron donor tetrakis(dimethylamino)ethylene (TDAE) with light-emitting diodes at 440 or 390 nm provides a stoichiometric reductant that is able to reduce aryl chlorides and fluorides. The method is very simple and requires only TDAE, substrate, and solvent at room temperature. The photoactive excited state of TDAE has a lifetime of 17.3 ns in cyclohexane at room temperature and an oxidation potential of ca.-3.4 V vs. SCE. This makes TDAE one of the strongest photoreductants able to operate on the basis of single excitation with visible photons. Direct substrate activation occurs in benzene, but acetone is reduced by photoexcited TDAE and substrate reduction takes place by a previously unexplored solvent radical anion mechanism. Our work shows that solvent can have a leveling effect on the photochemically available redox power, reminiscent of the pH-leveling effect that solvent has in acid-base chemistry.
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Affiliation(s)
- Felix Glaser
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Christopher B Larsen
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Christoph Kerzig
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Oliver S Wenger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland.
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37
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Sartor SM, Chrisman CH, Pearson RM, Miyake GM, Damrauer NH. Designing High-Triplet-Yield Phenothiazine Donor–Acceptor Complexes for Photoredox Catalysis. J Phys Chem A 2020; 124:817-823. [DOI: 10.1021/acs.jpca.9b10400] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Steven M. Sartor
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Cameron H. Chrisman
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Ryan M. Pearson
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Garret M. Miyake
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Niels H. Damrauer
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
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38
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Shibutani S, Kodo T, Takeda M, Nagao K, Tokunaga N, Sasaki Y, Ohmiya H. Organophotoredox-Catalyzed Decarboxylative C(sp 3)-O Bond Formation. J Am Chem Soc 2020; 142:1211-1216. [PMID: 31898903 DOI: 10.1021/jacs.9b12335] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This manuscript reports a visible-light-mediated organosulfide catalysis that enables the decarboxylative coupling between simple aliphatic alcohol and tertiary or secondary alkyl carboxylic acid-derived redox active esters to produce a C(sp3)-O-C(sp3) fragment. Results of the coupling using other heteroatom nucleophiles such as water, amides, and thiols are also described.
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Affiliation(s)
- Shotaro Shibutani
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences , Kanazawa University , Kakuma-machi, Kanazawa 920-1192 , Japan
| | - Taiga Kodo
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences , Kanazawa University , Kakuma-machi, Kanazawa 920-1192 , Japan
| | - Mitsutaka Takeda
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences , Kanazawa University , Kakuma-machi, Kanazawa 920-1192 , Japan
| | - Kazunori Nagao
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences , Kanazawa University , Kakuma-machi, Kanazawa 920-1192 , Japan
| | - Norihito Tokunaga
- Drug Discovery Chemistry Laboratories, Neuroscience Drug Discovery Unit , Takeda Pharmaceutical Company, Ltd. , 2-26-1, Muraoka-Higashi , Fujisawa, Kanagawa 251-8555 , Japan
| | - Yusuke Sasaki
- Drug Discovery Chemistry Laboratories, Neuroscience Drug Discovery Unit , Takeda Pharmaceutical Company, Ltd. , 2-26-1, Muraoka-Higashi , Fujisawa, Kanagawa 251-8555 , Japan
| | - Hirohisa Ohmiya
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences , Kanazawa University , Kakuma-machi, Kanazawa 920-1192 , Japan.,JST, PRESTO , 4-1-8 Honcho , Kawaguchi , Saitama 332-0012 , Japan
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39
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Rombach D, Wagenknecht H. Photoredox Catalytic α-Alkoxypentafluorosulfanylation of α-Methyl- and α-Phenylstyrene Using SF 6. Angew Chem Int Ed Engl 2020; 59:300-303. [PMID: 31680388 PMCID: PMC6973110 DOI: 10.1002/anie.201910830] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 10/03/2019] [Indexed: 11/22/2022]
Abstract
SF6 was applied as pentafluorosulfanylation reagent to prepare ethers with a vicinal SF5 substituent through a one-step method involving photoredox catalysis. This method shows a broad substrate scope with respect to applicable alcohols for the conversion of α-methyl and α-phenyl styrenes. The products bear a new structural motif with two functional groups installed in one step. The alkoxy group allows elimination and azidation as further transformations into valuable pentafluorosulfanylated compounds. These results confirm that non-toxic SF6 is a useful SF5 transfer reagent if properly activated by photoredox catalysis, and toxic reagents are completely avoided. In combination with light as an energy source, a high level of sustainability is achieved. Through this method, the proposed potential of the SF5 substituent in medicinal chemistry, agrochemistry, and materials chemistry may be exploited in the future.
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Affiliation(s)
- David Rombach
- Karlsruhe Institute of Technology (KIT)Institute of Organic ChemistryFritz-Haber-Weg 6KarlsruheGermany
| | - Hans‐Achim Wagenknecht
- Karlsruhe Institute of Technology (KIT)Institute of Organic ChemistryFritz-Haber-Weg 6KarlsruheGermany
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40
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Mayer L, May L, Müller TJJ. The interplay of conformations and electronic properties in N-aryl phenothiazines. Org Chem Front 2020. [DOI: 10.1039/d0qo00182a] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Extra and intra conformations govern electronic properties of N-aryl phenothiazines as shown by combined experimental and computational structure–property relationships.
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Affiliation(s)
- Laura Mayer
- Heinrich-Heine-Universität Düsseldorf
- Institut für Organische Chemie und Makromolekulare Chemie
- D-40225 Düsseldorf
- Germany
| | - Lars May
- Heinrich-Heine-Universität Düsseldorf
- Institut für Organische Chemie und Makromolekulare Chemie
- D-40225 Düsseldorf
- Germany
| | - Thomas J. J. Müller
- Heinrich-Heine-Universität Düsseldorf
- Institut für Organische Chemie und Makromolekulare Chemie
- D-40225 Düsseldorf
- Germany
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41
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Levernier E, Lévêque C, Derat E, Fensterbank L, Ollivier C. Towards Visible‐Light Photocatalytic Reduction of Hypercoordinated Silicon Species. Helv Chim Acta 2019. [DOI: 10.1002/hlca.201900238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Etienne Levernier
- Sorbonne UniversitéCNRSInstitut Parisien de Chimie Moléculaire 4 Place Jussieu, CC 229 FR-75252 Paris Cedex 05 France
| | - Christophe Lévêque
- Sorbonne UniversitéCNRSInstitut Parisien de Chimie Moléculaire 4 Place Jussieu, CC 229 FR-75252 Paris Cedex 05 France
| | - Etienne Derat
- Sorbonne UniversitéCNRSInstitut Parisien de Chimie Moléculaire 4 Place Jussieu, CC 229 FR-75252 Paris Cedex 05 France
| | - Louis Fensterbank
- Sorbonne UniversitéCNRSInstitut Parisien de Chimie Moléculaire 4 Place Jussieu, CC 229 FR-75252 Paris Cedex 05 France
| | - Cyril Ollivier
- Sorbonne UniversitéCNRSInstitut Parisien de Chimie Moléculaire 4 Place Jussieu, CC 229 FR-75252 Paris Cedex 05 France
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42
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Rombach D, Wagenknecht H. Photoredoxkatalytische α‐Alkoxypentafluorosulfanylierung von α‐Methyl‐ und α‐Phenylstyrol mithilfe von SF
6. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201910830] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- David Rombach
- Karlsruher Institut für Technologie (KIT) Institut für Organische Chemie Fritz-Haber-Weg 6 Karlsruhe Deutschland
| | - Hans‐Achim Wagenknecht
- Karlsruher Institut für Technologie (KIT) Institut für Organische Chemie Fritz-Haber-Weg 6 Karlsruhe Deutschland
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43
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Reiß B, Wagenknecht HA. Naphthalene diimides with improved solubility for visible light photoredox catalysis. Beilstein J Org Chem 2019; 15:2043-2051. [PMID: 31501672 PMCID: PMC6720061 DOI: 10.3762/bjoc.15.201] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 08/12/2019] [Indexed: 12/11/2022] Open
Abstract
Five core-substituted naphthalene diimides bearing two dialkylamino groups were synthesized as potential visible light photoredox catalysts and characterized by methods of optical spectroscopy and electrochemistry in comparison with one unsubstituted naphthalene diimide as reference. The core-substituted naphthalene diimides differ by the alkyl groups at the imide nitrogens and at the nitrogens of the two substituents at the core in order to enhance their solubility in DMF and thereby enhance their photoredox catalytic potential. The 1-ethylpropyl group as rather short and branched alkyl substituent at the imide nitrogen and the n-propyl group as short and unbranched one at the core amines yielded the best solubilities. The electron-donating diaminoalkyl substituents together with the electron-deficient aromatic core of the naphthalene diimides increase the charge-transfer character of their photoexcited states and thus shift their absorption into the visible light (500-650 nm). The excited state reduction potential was estimated to be approximately +1.0 V (vs SCE) which is sufficient to photocatalyze typical organic reactions. The photoredox catalytic activity in the visible light range was tested by the α-alkylation of 1-octanal as benchmark reaction. Irradiations were performed with LEDs in the visible light range between 520 nm and 640 nm. The irradiation by visible light together with the use of an organic dye instead of a transition metal complex as photoredox catalyst improve the sustainability and make photoredox catalysis "greener".
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Affiliation(s)
- Barbara Reiß
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
| | - Hans-Achim Wagenknecht
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
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