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Brufani G, Di Erasmo B, Li CJ, Vaccaro L. Csp 2-H functionalization of phenols: an effective access route to valuable materials via Csp 2-C bond formation. Chem Sci 2024; 15:3831-3871. [PMID: 38487228 PMCID: PMC10935747 DOI: 10.1039/d4sc00687a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 02/02/2024] [Indexed: 03/17/2024] Open
Abstract
In the vast majority of top-selling pharmaceutical and industrial products, phenolic structural motifs are highly prevalent. Non-functionalized simple phenols serve as building blocks in the synthesis of value-added chemicals. It is worth mentioning that lignin, being the largest renewable biomass source of aromatic building blocks in nature, mainly consists of phenolic units, which enable the production of structurally diverse phenols. Given their remarkable applicability in the chemical value chain, many efforts have been devoted to increasing the molecular complexity of the phenolic scaffold. Among the key techniques, direct functionalization of Csp2-H is a powerful tool, enabling the construction of new Csp2-C bonds in an economical and atomic manner. Herein we present and summarize the large plethora of direct Csp2-H functionalization methods that enables scaffold diversification of simple, unprotected phenols, leading to the formation of new Csp2-C bonds. In this review article, we intend to summarize the contributions that appeared in the literature mainly in the last 5 years dealing with the functionalization of unprotected phenols, both catalytic and non-catalytic. Our goal is to highlight the key findings and the ongoing challenges in the stimulating and growing research dedicated to the development of new protocols for the valorization of phenols.
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Affiliation(s)
- Giulia Brufani
- Laboratory of Green S.O.C., Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia Via Elce di Sotto 8 06123 Perugia Italy https://greensoc.chm.unipg.it
| | - Benedetta Di Erasmo
- Laboratory of Green S.O.C., Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia Via Elce di Sotto 8 06123 Perugia Italy https://greensoc.chm.unipg.it
- Department of Chemistry, FRQNT Centre for Green Chemistry and Catalysis, McGill University 801 Sherbrooke Street West Montreal QC H3A0B8 Canada
| | - Chao-Jun Li
- Department of Chemistry, FRQNT Centre for Green Chemistry and Catalysis, McGill University 801 Sherbrooke Street West Montreal QC H3A0B8 Canada
| | - Luigi Vaccaro
- Laboratory of Green S.O.C., Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia Via Elce di Sotto 8 06123 Perugia Italy https://greensoc.chm.unipg.it
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2
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Li Y, Huang Y, Li Z, Sun J. Recent Advances in Regioselective C-H Bond Functionalization of Free Phenols. Molecules 2023; 28:molecules28083397. [PMID: 37110630 PMCID: PMC10143084 DOI: 10.3390/molecules28083397] [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: 03/17/2023] [Revised: 04/08/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023] Open
Abstract
Phenols are important readily available synthetic building blocks and starting materials for organic synthetic transformations, which are widely found in agrochemicals, pharmaceuticals, and functional materials. The C-H functionalization of free phenols has proven to be an extremely useful tool in organic synthesis, which provides efficient increases in phenol molecular complexity. Therefore, approaches to functionalizing existing C-H bonds of free phenols have continuously attracted the attention of organic chemists. In this review, we summarize the current knowledge and recent advances in ortho-, meta-, and para-selective C-H functionalization of free phenols in the last five years.
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Affiliation(s)
- Yanan Li
- School of Chemical Engineering, Anhui University of Science and Technology, Huainan 232001, China
| | - Yekai Huang
- School of Chemical Engineering, Anhui University of Science and Technology, Huainan 232001, China
| | - Zhi Li
- School of Chemical Engineering, Anhui University of Science and Technology, Huainan 232001, China
| | - Jianan Sun
- School of Biomedical Engineering, Anhui Medical University, Hefei 230032, China
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3
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Motiwala HF, Armaly AM, Cacioppo JG, Coombs TC, Koehn KRK, Norwood VM, Aubé J. HFIP in Organic Synthesis. Chem Rev 2022; 122:12544-12747. [PMID: 35848353 DOI: 10.1021/acs.chemrev.1c00749] [Citation(s) in RCA: 117] [Impact Index Per Article: 58.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
1,1,1,3,3,3-Hexafluoroisopropanol (HFIP) is a polar, strongly hydrogen bond-donating solvent that has found numerous uses in organic synthesis due to its ability to stabilize ionic species, transfer protons, and engage in a range of other intermolecular interactions. The use of this solvent has exponentially increased in the past decade and has become a solvent of choice in some areas, such as C-H functionalization chemistry. In this review, following a brief history of HFIP in organic synthesis and an overview of its physical properties, literature examples of organic reactions using HFIP as a solvent or an additive are presented, emphasizing the effect of solvent of each reaction.
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Affiliation(s)
- Hashim F Motiwala
- Divison of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 United States
| | - Ahlam M Armaly
- Divison of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 United States
| | - Jackson G Cacioppo
- Divison of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 United States
| | - Thomas C Coombs
- Department of Chemistry, University of North Carolina Wilmington, Wilmington, North Carolina 28403 United States
| | - Kimberly R K Koehn
- Divison of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 United States
| | - Verrill M Norwood
- Divison of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 United States
| | - Jeffrey Aubé
- Divison of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 United States
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Abstract
Phenols and their derivatives are the elementary building blocks for several classes of complex molecules that play essential roles in biological systems. Nature has devised methods to selectively couple phenolic compounds, and many efforts have been undertaken by chemists to mimic such coupling processes. A range of mechanisms can be involved and with well-studied catalysts, reaction outcomes in phenol-phenol oxidative coupling reactions can be predicted with a good level of fidelity. However, reactions with catalysts that have not been studied or that do not behave similarly to known catalysts can be hard to predict and control. This Perspective provides an overview of catalytic methods for the oxidative coupling of phenols, focusing on the last 10 years, and summarizes current challenges.
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Affiliation(s)
- Jingze Wu
- Department of Chemistry, Roy and Diana Vagelos Laboratories, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Marisa C Kozlowski
- Department of Chemistry, Roy and Diana Vagelos Laboratories, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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5
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Liu S, Lu Y, Sun S, Wang H, Gao W, Wang Y, Jia X, Chen J. Electrode material promoted dehydrogenative homo-/cross-coupling of weakly activated naphthalenes. GREEN SYNTHESIS AND CATALYSIS 2022. [DOI: 10.1016/j.gresc.2022.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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6
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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: 131] [Impact Index Per Article: 65.5] [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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7
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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: 163] [Impact Index Per Article: 81.5] [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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8
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Sugawara M, Ohnishi R, Ezawa T, Akakabe M, Sawamura M, Hojo D, Hashizume D, Sohtome Y, Sodeoka M. Regiodivergent Oxidative Cross-Coupling of Catechols with Persistent tert-Carbon Radicals. ACS Catal 2020. [DOI: 10.1021/acscatal.0c03986] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Masumi Sugawara
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Rikako Ohnishi
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan
| | - Tetsuya Ezawa
- RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Mai Akakabe
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Miki Sawamura
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Daiki Hojo
- RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Daisuke Hashizume
- RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yoshihiro Sohtome
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Mikiko Sodeoka
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan
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9
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Patel SB, Vasava DV. The Study on Encapsulation of Copper Nanoparticles in Modified Poly‐Styrene Resin Metrix and its Catalytic Evaluation in Microwave‐Assisted Sonogashira Coupling. ChemistrySelect 2020. [DOI: 10.1002/slct.202001106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Sunil B. Patel
- Chemistry School of Sciences, department of chemistryGujarat University, Navrangpura Ahmedabad 380009 India
| | - Dilip V. Vasava
- Chemistry School of Sciences, department of chemistryGujarat University, Navrangpura Ahmedabad 380009 India
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10
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Neuhaus WC, Kozlowski MC. Total Synthesis of Pyrolaside B: Phenol Trimerization through Sequenced Oxidative C−C and C−O Coupling. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201915654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- William C. Neuhaus
- Department of Chemistry University of Pennsylvania Philadelphia PA 19104 USA
| | - Marisa C. Kozlowski
- Department of Chemistry University of Pennsylvania Philadelphia PA 19104 USA
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11
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Neuhaus WC, Kozlowski MC. Total Synthesis of Pyrolaside B: Phenol Trimerization through Sequenced Oxidative C-C and C-O Coupling. Angew Chem Int Ed Engl 2020; 59:7842-7847. [PMID: 32026544 PMCID: PMC7200290 DOI: 10.1002/anie.201915654] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Indexed: 01/05/2023]
Abstract
A facile method to oxidatively trimerize phenols using a catalytic aerobic copper system is described. The mechanism of this transformation was probed, yielding insight that enabled cross-coupling trimerizations. With this method, the natural product pyrolaside B was synthesized for the first time. The key strategy used for this novel synthesis is the facile one-step construction of a spiroketal trimer intermediate, which can be selectively reduced to give the natural product framework without recourse to stepwise Ullmann- and Suzuki-type couplings. As a result, pyrolaside B can be obtained expeditiously in five steps and 16 % overall yield. Three other analogues were synthesized, thus highlighting the utility of the method, which provides new accessibility to this area of chemical space. A novel xanthene was also synthesized through controlled Lewis acid promoted rearrangement of a spiroketal trimer.
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Affiliation(s)
| | - Marisa C. Kozlowski
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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12
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Okamoto K, Chiba K. Electrochemical Total Synthesis of Pyrrolophenanthridone Alkaloids: Controlling the Anodically Initiated Electron Transfer Process. Org Lett 2020; 22:3613-3617. [PMID: 32286833 DOI: 10.1021/acs.orglett.0c01082] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Electrochemical intramolecular C(sp2)-H cross-coupling and dehydrogenative indole synthesis were developed. Both reactions were initiated by anodic oxidation of the same electron-rich indoline moiety, but the product selectivity was controlled by different electron-transfer processes. Intramolecular cross-coupling was achieved by the generation of a strong electrophilic radical cation intermediate in the MeNO2-HFIP-LiClO4 system. Indole formation was accomplished through benzylic oxidation and continuous deprotonation. We applied these reactions to the total synthesis of natural pyrrolophenanthridone alkaloids.
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Affiliation(s)
- Kazuhiro Okamoto
- Department of Applied Biological Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Kazuhiro Chiba
- Department of Applied Biological Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
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13
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Synthesis of a Bcl9 Alpha-Helix Mimetic for Inhibition of PPIs by a Combination of Electrooxidative Phenol Coupling and Pd-Catalyzed Cross Coupling. Catalysts 2020. [DOI: 10.3390/catal10030340] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Teraryl-based alpha-helix mimetics have resulted in efficient inhibitors of protein-protein interactions (PPIs). Extending the concept to even longer oligoarene systems would allow for the mimicking of even larger interaction sites. We present a highly efficient synthetic modular access to quateraryl alpha-helix mimetics, in which, at first, two phenols undergo electrooxidative dehydrogenative cross-coupling. The resulting 4,4′-biphenol is then activated by conversion to nonaflates, which serve as leaving groups for iterative Pd-catalyzed Suzuki-cross-coupling reactions with suitably substituted pyridine boronic acids. This work, for the first time, demonstrates the synthetic efficiency of using both electroorganic as well as transition-metal catalyzed cross-coupling in the assembly of oligoarene structures.
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14
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Hayashi H, Ueno T, Kim C, Uchida T. Ruthenium-Catalyzed Cross-Selective Asymmetric Oxidative Coupling of Arenols. Org Lett 2020; 22:1469-1474. [DOI: 10.1021/acs.orglett.0c00048] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hiroki Hayashi
- Faculty of Arts and Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Takamasa Ueno
- Department of Chemistry, Graduate School of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Chungsik Kim
- International Institute of Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Tatsuya Uchida
- Faculty of Arts and Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- International Institute of Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
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15
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Röckl JL, Pollok D, Franke R, Waldvogel SR. A Decade of Electrochemical Dehydrogenative C,C-Coupling of Aryls. Acc Chem Res 2020; 53:45-61. [PMID: 31850730 DOI: 10.1021/acs.accounts.9b00511] [Citation(s) in RCA: 225] [Impact Index Per Article: 56.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The importance of sustainable and green synthetic protocols for the synthesis of fine chemicals has rapidly increased during the last decades in an effort to reduce the use of fossil fuels and other finite resources. The replacement of common reagents by electricity provides a cost- and atom-efficient, environmentally friendly, and inherently safe access to novel synthetic routes. The selective formation of carbon-carbon bonds between two distinct substrates is a crucial tool in organic chemistry. This fundamental transformation enables access to a broad variety of complex molecular architectures. In particular, the aryl-aryl bond formation has high significance for the preparation of organic materials, drugs, and natural products. Besides well-known and well-established reductive- and oxidative-reagent-mediated or transition-metal-catalyzed coupling reactions, novel synthetic protocols have arisen, which require fewer steps than conventional synthetic approaches. Electroorganic conversions can be categorized according to the nature of the electron transfer processes occurring. Direct transformations at inert electrode materials are environmentally benign and cost-effective, whereas catalytic processes at active electrodes and mediated electrosynthesis using an additional soluble reagent can have beneficial properties in terms of selectivity and reactivity. In general, these conversions require challenging optimization of the reaction parameters and the appropriate cell design. Galvanostatic reactions enable fast conversions with a rather simple setup, whereas potentiostatic electrolysis may enhance selectivity. This Account discusses the development of seminal carbon-carbon bond formations over the past two decades, focusing on phenols leading to precursors for ligands in, e.g., hydroformylation reaction. A key element in the success of these electrochemical transformations is the application of electrochemically inert, non-nucleophilic, highly fluorinated alcohols such as 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), which exhibit a large potential window for transformations and enable selective cross-coupling reactions. This selectivity is based on the capability of HFIP to stabilize organic radicals. Inert, carbon-based and metal-free electrode materials like graphite or boron-doped diamond (BDD) open up novel electroorganic pathways. Furthermore, novel active electrode materials have been developed to enable intra- and intermolecular dehydrogenative coupling reactions of electron-rich aryls. The application of 2,2'-biphenol derivatives as ligand components for catalysts requires reactions to be carried out on larger scale. In order to achieve this, continuous flow transformations have been established to overcome the drawbacks of heat transfer, overconversion, and conductivity. Modular cell designs enable the transfer of a broad variety of electroorganic conversions into continuous processes. Recent results demonstrate the application of organic electrochemistry to natural product synthesis of the pharmaceutically relevant opiate alkaloids (-)-thebaine or (-)-oxycodone.
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Affiliation(s)
- Johannes L. Röckl
- Graduate School Materials Science in Mainz, Staudingerweg 9, 55128 Mainz, Germany
| | - Dennis Pollok
- Institute of Organic Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Robert Franke
- Evonik Performance Materials GmbH, Paul-Baumann-Str. 1, 45772 Marl, Germany
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, Universitätstraße 150, 44801 Bochum, Germany
| | - Siegfried R. Waldvogel
- Institute of Organic Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
- Graduate School Materials Science in Mainz, Staudingerweg 9, 55128 Mainz, Germany
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16
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Röckl JL, Schollmeyer D, Franke R, Waldvogel SR. Dehydrogenative Anodic C-C Coupling of Phenols Bearing Electron-Withdrawing Groups. Angew Chem Int Ed Engl 2020; 59:315-319. [PMID: 31498544 PMCID: PMC6973026 DOI: 10.1002/anie.201910077] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Indexed: 01/24/2023]
Abstract
We herein present a metal-free, electrosynthetic method that enables the direct dehydrogenative coupling reactions of phenols carrying electron-withdrawing groups for the first time. The reactions are easy to conduct and scalable, as they are carried out in undivided cells and obviate the necessity for additional supporting electrolyte. As such, this conversion is efficient, practical, and thereby environmentally friendly, as production of waste is minimized. The method features a broad substrate scope, and a variety of functional groups are tolerated, providing easy access to precursors for novel polydentate ligands and even heterocycles such as dibenzofurans.
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Affiliation(s)
- Johannes L. Röckl
- Institute of Organic ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128Mainz (Germany)
- Graduate School Materials Science in MainzGermany
| | - Dieter Schollmeyer
- Institute of Organic ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128Mainz (Germany)
| | - Robert Franke
- Evonik Performance Materials GmbHPaul-Baumann-Str. 145772MarlGermany
- Lehrstuhl für Theoretische ChemieRuhr-Universität BochumUniversitätstraße 15044801BochumGermany
| | - Siegfried R. Waldvogel
- Institute of Organic ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128Mainz (Germany)
- Graduate School Materials Science in MainzGermany
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17
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Gleede B, Selt M, Gütz C, Stenglein A, Waldvogel SR. Large, Highly Modular Narrow-Gap Electrolytic Flow Cell and Application in Dehydrogenative Cross-Coupling of Phenols. Org Process Res Dev 2019. [DOI: 10.1021/acs.oprd.9b00451] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Barbara Gleede
- Institute of Organic Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Maximilian Selt
- Institute of Organic Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Christoph Gütz
- Institute of Organic Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Andreas Stenglein
- Institute of Organic Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Siegfried R. Waldvogel
- Institute of Organic Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
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Röckl JL, Schollmeyer D, Franke R, Waldvogel SR. Dehydrierende anodische C‐C‐Kupplung von Phenolen mit elektronenziehenden Substituenten. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201910077] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Johannes L. Röckl
- Institut für Organische Chemie Johannes Gutenberg Universität Mainz Duesbergweg 10–14 55128 Mainz Deutschland
- Graduate School Materials Science in Mainz Deutschland
| | - Dieter Schollmeyer
- Institut für Organische Chemie Johannes Gutenberg Universität Mainz Duesbergweg 10–14 55128 Mainz Deutschland
| | - Robert Franke
- Evonik Performance Materials GmbH Paul-Baumann-Straße 1 45772 Marl Deutschland
- Lehrstuhl für Theoretische Chemie Ruhr-Universität Bochum Universitätstraße 150 44801 Bochum Deutschland
| | - Siegfried R. Waldvogel
- Institut für Organische Chemie Johannes Gutenberg Universität Mainz Duesbergweg 10–14 55128 Mainz Deutschland
- Graduate School Materials Science in Mainz Deutschland
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19
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Xiong M, Liang X, Gao Z, Lei A, Pan Y. Synthesis of Isoxazolines and Oxazines by Electrochemical Intermolecular [2 + 1 + n] Annulation: Diazo Compounds Act as Radical Acceptors. Org Lett 2019; 21:9300-9305. [PMID: 31713430 DOI: 10.1021/acs.orglett.9b03306] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reported herein is an unprecedented synthesis of isoxazolines and oxazines through electrochemical intermolecular annulation of alkenes with tert-butyl nitrite, in which diazo compounds serve as radical acceptors. Notably, [2 + 1 + 2] and [2 + 1 + 3] annulations occur when styrenes and allylbenzenes are used as substrates, respectively. The latter reaction undergoes group migration to form more stable radical, manifesting radical route instead of conventional 1,3-dipolar cycloaddition occurs. Moreover, scale-up experiments suggest the potential application value of these transformations in industry.
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Affiliation(s)
- Mingteng Xiong
- Department of Chemistry , Zhejiang University , Hangzhou 310027 , Zhejiang , P. R. China
| | - Xiao Liang
- Department of Chemistry , Zhejiang University , Hangzhou 310027 , Zhejiang , P. R. China
| | - Zhan Gao
- Department of Chemistry , Zhejiang University , Hangzhou 310027 , Zhejiang , P. R. China
| | - Aiwen Lei
- The Institute for Advanced Studies (IAS), College of Chemistry and Molecular Sciences , Wuhan University , Wuhan 430072 , P. R. China
| | - Yuanjiang Pan
- Department of Chemistry , Zhejiang University , Hangzhou 310027 , Zhejiang , P. R. China
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20
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Matsumoto K, Takeda S, Hirokane T, Yoshida M. A Highly Selective Palladium-Catalyzed Aerobic Oxidative Aniline–Aniline Cross-Coupling Reaction. Org Lett 2019; 21:7279-7283. [DOI: 10.1021/acs.orglett.9b02527] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Kenji Matsumoto
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, 180 Nishihama-Boji, Yamashiro-cho, Tokushima 770-8514, Japan
| | - Satoshi Takeda
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, 180 Nishihama-Boji, Yamashiro-cho, Tokushima 770-8514, Japan
| | - Tsukasa Hirokane
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, 180 Nishihama-Boji, Yamashiro-cho, Tokushima 770-8514, Japan
| | - Masahiro Yoshida
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, 180 Nishihama-Boji, Yamashiro-cho, Tokushima 770-8514, Japan
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21
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Nieves-Quinones Y, Paniak TJ, Lee YE, Kim SM, Tcyrulnikov S, Kozlowski MC. Chromium-Salen Catalyzed Cross-Coupling of Phenols: Mechanism and Origin of the Selectivity. J Am Chem Soc 2019; 141:10016-10032. [PMID: 31125210 DOI: 10.1021/jacs.9b03890] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A highly chemoselective phenol cross-coupling reaction catalyzed by a Cr-salen catalyst was developed. Kinetic studies showed that the oxidation of Cr(III) to Cr(V) is the rate-determining step of the reaction. In addition, experimental stoichiometric analysis showed that a high valent Cr(V) species is the active catalyst for this process. The selectivity of the reaction was found to be determined by the cross-coupling carbon-carbon bond forming reaction, rather than any precoordination species. It appears that the lowest energy cross-coupling pathway requires a lesser degree of electronic reorganization in its transition state vs the lowest energy homocoupling pathway. This result was supported by stoichiometric Cr(V) kinetics, 13C kinetic isotope effects, and density functional theory (DFT) calculations. The understanding of the full landscape of this reaction allowed us to develop a general analysis to predict the regioselectivity of the cross-coupling reaction.
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Affiliation(s)
- Yexenia Nieves-Quinones
- Department of Chemistry, Roy and Diana Vagelos Laboratories , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Thomas J Paniak
- Department of Chemistry, Roy and Diana Vagelos Laboratories , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Young Eun Lee
- Department of Chemistry, Roy and Diana Vagelos Laboratories , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Sun Min Kim
- Department of Chemistry, Roy and Diana Vagelos Laboratories , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Sergei Tcyrulnikov
- Department of Chemistry, Roy and Diana Vagelos Laboratories , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Marisa C Kozlowski
- Department of Chemistry, Roy and Diana Vagelos Laboratories , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
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22
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Schön F, Kaifer E, Himmel H. Catalytic Aerobic Phenol Homo‐ and Cross‐Coupling Reactions with Copper Complexes Bearing Redox‐Active Guanidine Ligands. Chemistry 2019; 25:8279-8288. [DOI: 10.1002/chem.201900583] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Indexed: 01/12/2023]
Affiliation(s)
- Florian Schön
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Elisabeth Kaifer
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Hans‐Jörg Himmel
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
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