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Yang X, Zhang G, Zhou J, Zhou C, Wang L, Li P. Microwave-promoted radical addition/cyclization of biaryl vinyl ketones with diacyl peroxides in water under metal-free conditions. Org Biomol Chem 2023; 21:4018-4021. [PMID: 37128770 DOI: 10.1039/d3ob00115f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
This communication reports an efficient microwave-promoted radical addition/cyclization reaction of biaryl vinyl ketones with diacyl peroxides in water under metal-free conditions. A series of 10-methyl-10-benzyl(alkyl)phenanthren-9(10H)-ones were obtained in high yields with good functional group tolerance.
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Affiliation(s)
- Xingyu Yang
- College of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, P. R. China.
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education, College of Chemistry and Materials Science, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China.
| | - Gan Zhang
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education, College of Chemistry and Materials Science, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China.
| | - Jingwen Zhou
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education, College of Chemistry and Materials Science, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China.
| | - Chao Zhou
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education, College of Chemistry and Materials Science, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China.
| | - Lei Wang
- Advanced Research Institute and Department of Chemistry, Taizhou University, Taizhou, Zhejiang 318000, P. R. China
| | - Pinhua Li
- College of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, P. R. China.
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2
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El Gehani AAMA, Maashi HA, Harnedy J, Morrill LC. Electrochemical generation and utilization of alkoxy radicals. Chem Commun (Camb) 2023; 59:3655-3664. [PMID: 36877137 DOI: 10.1039/d3cc00302g] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
This highlight summarises electrochemical approaches for the generation and utilization of alkoxy radicals, predominantly focusing on recent advances (2012-present). The application of electrochemically generated alkoxy radicals in a diverse range of transformations is described, including discussion on reaction mechanisms, scope and limitations, in addition to highlighting future challenges in this burgeoning area of sustainable synthesis.
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Affiliation(s)
- Albara A M A El Gehani
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK.
| | - Hussain A Maashi
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK.
| | - James Harnedy
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK.
| | - Louis C Morrill
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK.
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3
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Harnedy J, Maashi HA, El Gehani AAMA, Burns M, Morrill LC. Deconstructive Functionalization of Unstrained Cycloalkanols via Electrochemically Generated Aromatic Radical Cations. Org Lett 2023; 25:1486-1490. [PMID: 36847269 PMCID: PMC10012273 DOI: 10.1021/acs.orglett.3c00219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
Herein we report an electrochemical approach for the deconstructive functionalization of cycloalkanols, where various alcohols, carboxylic acids, and N-heterocycles are employed as nucleophiles. The method has been demonstrated across a broad range of cycloalkanol substrates, including various ring sizes and substituents, to access useful remotely functionalized ketone products (36 examples). The method was demonstrated on a gram scale via single-pass continuous flow, which exhibited increased productivity in relation to the batch process.
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Affiliation(s)
- James Harnedy
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K
| | - Hussain A Maashi
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K
| | - Albara A M A El Gehani
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K
| | - Matthew Burns
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield SK10 2NA, U.K
| | - Louis C Morrill
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K
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4
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Quiclet-Sire B, Zard SZ. The xanthate route to tetralones, tetralins, and naphthalenes. A brief account. Org Biomol Chem 2023; 21:910-924. [PMID: 36607600 DOI: 10.1039/d2ob02159e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The present account summarises routes to tetralones, tetralines, and naphthalenes based on the chemistry of xanthates developed in the authors' laboratory. The degenerative reversible transfer of xanthates allows radical addition even to unactivated, electronically unbiased alkenes, and tolerates a broad range of functional groups, in particular common polar groups such as esters, ketones, nitriles, amides, carbamates, etc. Xanthates also allow radical ring closures onto aromatic rings. This feature, in combination with the intermolecular addition to alkenes, can be used to construct tetralones and tetralines. With the appropriate appendages, the former can be converted into napthalenes with a variety of substitution patterns. This translates into a convergent approach to a vast array of building blocks of interest to the pharmaceutical and agrochemical industries, and to material sciences.
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Affiliation(s)
- Béatrice Quiclet-Sire
- Laboratoire de Synthèse Organique UMR 7652, Ecole Polytechnique, 91128 Palaiseau, France.
| | - Samir Z Zard
- Laboratoire de Synthèse Organique UMR 7652, Ecole Polytechnique, 91128 Palaiseau, France.
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5
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Parsons PJ, Natho P, Allen LAT. A Cyclobutanol Ring-Expansion Approach to Oxygenated Carbazoles: Total Synthesis of Glycoborine, Carbazomycin A and Carbazomycin B. Synlett 2023. [DOI: 10.1055/s-0042-1751411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
AbstractThe transition-metal-free total syntheses of the oxygenated carbazole natural products glycoborine, carbazomycin A and carbazomycin B are reported. The key step involves an NBS-mediated cyclobutanol ring expansion to 4-tetralones for the preparation of the tricyclic carbazole core.
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6
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Hareram MD, El Gehani AAMA, Harnedy J, Seastram AC, Jones AC, Burns M, Wirth T, Browne DL, Morrill LC. Electrochemical Deconstructive Functionalization of Cycloalkanols via Alkoxy Radicals Enabled by Proton-Coupled Electron Transfer. Org Lett 2022; 24:3890-3895. [PMID: 35604008 PMCID: PMC9171832 DOI: 10.1021/acs.orglett.2c01552] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
![]()
Herein, we report
a new electrochemical method for alkoxy radical
generation from alcohols using a proton-coupled electron transfer
(PCET) approach, showcased via the deconstructive functionalization
of cycloalkanols. The electrochemical method is applicable across
a diverse array of substituted cycloalkanols, accessing a broad range
of synthetically useful distally functionalized ketones. The orthogonal
derivatization of the products has been demonstrated through chemoselective
transformations, and the electrochemical process has been performed
on a gram scale in continuous single-pass flow.
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Affiliation(s)
- Mishra Deepak Hareram
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, United Kingdom
| | - Albara A. M. A. El Gehani
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, United Kingdom
| | - James Harnedy
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, United Kingdom
| | - Alex C. Seastram
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, United Kingdom
| | - Andrew C. Jones
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, United Kingdom
| | - Matthew Burns
- Chemical Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Macclesfield, SK10 2NA, United Kingdom
| | - Thomas Wirth
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, United Kingdom
| | - Duncan L. Browne
- Department of Pharmaceutical and Biological Chemistry, University College London, School of Pharmacy, London, W1CN 1AX, United Kingdom
| | - Louis C. Morrill
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, United Kingdom
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7
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Tay NES, Lehnherr D, Rovis T. Photons or Electrons? A Critical Comparison of Electrochemistry and Photoredox Catalysis for Organic Synthesis. Chem Rev 2022; 122:2487-2649. [PMID: 34751568 PMCID: PMC10021920 DOI: 10.1021/acs.chemrev.1c00384] [Citation(s) in RCA: 110] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Redox processes are at the heart of synthetic methods that rely on either electrochemistry or photoredox catalysis, but how do electrochemistry and photoredox catalysis compare? Both approaches provide access to high energy intermediates (e.g., radicals) that enable bond formations not constrained by the rules of ionic or 2 electron (e) mechanisms. Instead, they enable 1e mechanisms capable of bypassing electronic or steric limitations and protecting group requirements, thus enabling synthetic chemists to disconnect molecules in new and different ways. However, while providing access to similar intermediates, electrochemistry and photoredox catalysis differ in several physical chemistry principles. Understanding those differences can be key to designing new transformations and forging new bond disconnections. This review aims to highlight these differences and similarities between electrochemistry and photoredox catalysis by comparing their underlying physical chemistry principles and describing their impact on electrochemical and photochemical methods.
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Affiliation(s)
- Nicholas E S Tay
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Dan Lehnherr
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Tomislav Rovis
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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8
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Murray PD, Cox JH, Chiappini ND, Roos CB, McLoughlin EA, Hejna BG, Nguyen ST, Ripberger HH, Ganley JM, Tsui E, Shin NY, Koronkiewicz B, Qiu G, Knowles RR. Photochemical and Electrochemical Applications of Proton-Coupled Electron Transfer in Organic Synthesis. Chem Rev 2022; 122:2017-2291. [PMID: 34813277 PMCID: PMC8796287 DOI: 10.1021/acs.chemrev.1c00374] [Citation(s) in RCA: 150] [Impact Index Per Article: 75.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Indexed: 12/16/2022]
Abstract
We present here a review of the photochemical and electrochemical applications of multi-site proton-coupled electron transfer (MS-PCET) in organic synthesis. MS-PCETs are redox mechanisms in which both an electron and a proton are exchanged together, often in a concerted elementary step. As such, MS-PCET can function as a non-classical mechanism for homolytic bond activation, providing opportunities to generate synthetically useful free radical intermediates directly from a wide variety of common organic functional groups. We present an introduction to MS-PCET and a practitioner's guide to reaction design, with an emphasis on the unique energetic and selectivity features that are characteristic of this reaction class. We then present chapters on oxidative N-H, O-H, S-H, and C-H bond homolysis methods, for the generation of the corresponding neutral radical species. Then, chapters for reductive PCET activations involving carbonyl, imine, other X═Y π-systems, and heteroarenes, where neutral ketyl, α-amino, and heteroarene-derived radicals can be generated. Finally, we present chapters on the applications of MS-PCET in asymmetric catalysis and in materials and device applications. Within each chapter, we subdivide by the functional group undergoing homolysis, and thereafter by the type of transformation being promoted. Methods published prior to the end of December 2020 are presented.
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Affiliation(s)
- Philip
R. D. Murray
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - James H. Cox
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Nicholas D. Chiappini
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Casey B. Roos
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | | | - Benjamin G. Hejna
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Suong T. Nguyen
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Hunter H. Ripberger
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Jacob M. Ganley
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Elaine Tsui
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Nick Y. Shin
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Brian Koronkiewicz
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Guanqi Qiu
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Robert R. Knowles
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
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9
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Leclair A, Wang Q, Zhu J. Two-Carbon Ring Expansion of Cyclobutanols to Cyclohexenones Enabled by Indole Radical Cation Intermediate: Development and Application to a Total Synthesis of Uleine. ACS Catal 2022. [DOI: 10.1021/acscatal.1c05621] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Alexandre Leclair
- Laboratory of Synthesis and Natural Products, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH5304, CH-1015 Lausanne, Switzerland
| | - Qian Wang
- Laboratory of Synthesis and Natural Products, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH5304, CH-1015 Lausanne, Switzerland
| | - Jieping Zhu
- Laboratory of Synthesis and Natural Products, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH5304, CH-1015 Lausanne, Switzerland
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Leech MC, Petti A, Tanbouza N, Mastrodonato A, Goodall ICA, Ollevier T, Dobbs AP, Lam K. Anodic Oxidation of Aminotetrazoles: A Mild and Safe Route to Isocyanides. Org Lett 2021; 23:9371-9375. [PMID: 34841877 DOI: 10.1021/acs.orglett.1c03475] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new electrochemical method for the preparation of isocyanides from easily accessible aminotetrazole derivatives has been developed, which tolerates an unprecedented range of functional groups. The use of chemical, rather than electrochemical, oxidation to afford isocyanides was also demonstrated, which provides access to these compounds for those without electrosynthesis equipment. The practicality of scale-up using flow electrochemistry has been demonstrated, in addition to the possibility of using electrochemically generated isocyanides in further reactions.
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Affiliation(s)
- Matthew C Leech
- School of Science, University of Greenwich, Chatham Maritime, Kent, ME4 4TB, United Kingdom
| | - Alessia Petti
- School of Science, University of Greenwich, Chatham Maritime, Kent, ME4 4TB, United Kingdom
| | - Nour Tanbouza
- Département de Chimie, Université Laval, 1045 Avenue de la Médecine, Québec, QC, G1V 0A6, Canada
| | - Andrea Mastrodonato
- School of Science, University of Greenwich, Chatham Maritime, Kent, ME4 4TB, United Kingdom
| | - Iain C A Goodall
- School of Science, University of Greenwich, Chatham Maritime, Kent, ME4 4TB, United Kingdom
| | - Thierry Ollevier
- Département de Chimie, Université Laval, 1045 Avenue de la Médecine, Québec, QC, G1V 0A6, Canada
| | - Adrian P Dobbs
- School of Science, University of Greenwich, Chatham Maritime, Kent, ME4 4TB, United Kingdom
| | - Kevin Lam
- School of Science, University of Greenwich, Chatham Maritime, Kent, ME4 4TB, United Kingdom
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11
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Natho P, Yang Z, Allen LAT, Rey J, White AJP, Parsons PJ. An entry to 2-(cyclobut-1-en-1-yl)-1 H-indoles through a cyclobutenylation/deprotection cascade. Org Biomol Chem 2021; 19:4048-4053. [PMID: 33885127 DOI: 10.1039/d1ob00430a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A transition-metal-free strategy for the synthesis of 2-(cyclobut-1-en-1-yl)-1H-indoles under mild conditions is described herein. A series of substituted 2-(cyclobut-1-en-1-yl)-1H-indoles are accessed by a one-pot cyclobutenylation/deprotection cascade from N-Boc protected indoles. Preliminary experimental and density functional theory calculations suggest that a Boc-group transfer is involved in the underlying mechanism.
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Affiliation(s)
- Philipp Natho
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, W12 0BZ London, UK.
| | - Zeyu Yang
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, W12 0BZ London, UK.
| | - Lewis A T Allen
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, W12 0BZ London, UK.
| | - Juliette Rey
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, W12 0BZ London, UK.
| | - Andrew J P White
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, W12 0BZ London, UK.
| | - Philip J Parsons
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, W12 0BZ London, UK.
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