1
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Bieniek JC, Mashtakov B, Schollmeyer D, Waldvogel SR. Dehydrogenative Electrochemical Synthesis of N-Aryl-3,4-Dihydroquinolin-2-ones by Iodine(III)-Mediated Coupling Reaction. Chemistry 2024; 30:e202303388. [PMID: 38018461 DOI: 10.1002/chem.202303388] [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: 10/14/2023] [Revised: 11/12/2023] [Accepted: 11/23/2023] [Indexed: 11/30/2023]
Abstract
Electrochemically generated hypervalent iodine(III) species are powerful reagents for oxidative C-N coupling reactions, providing access to valuable N-heterocycles. A new electrocatalytic hypervalent iodine(III)-mediated in-cell synthesis of 1H-N-aryl-3,4-dihydroquinolin-2-ones by dehydrogenative C-N bond formation is presented. Catalytic amounts of the redox mediator, a low supporting electrolyte concentration and recycling of the solvent used make this method a sustainable alternative to electrochemical ex-cell or conventional approaches. Furthermore, inexpensive, readily available electrode materials and a simple galvanostatic set-up are applied. The broad functional group tolerance could be demonstrated by synthesizing 23 examples in yields up to 96 %, with one reaction being performed on a 10-fold higher scale. Based on the obtained results a sound reaction mechanism could be proposed.
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Affiliation(s)
- Jessica C Bieniek
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Boris Mashtakov
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Dieter Schollmeyer
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Siegfried R Waldvogel
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
- Institute of Biological and Chemical Systems - Functional Molecular Systems (IBCS-FMS), Kaiserstraße 12, 76131, Karlsruhe, Germany
- Max-Planck-Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470, Mülheim an der Ruhr, Germany
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2
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Ge J, Cai B, Zhu F, Gao Y, Wang X, Chen Q, Wang M, Jiao S. Natural Convection in Molten Salt Electrochemistry. J Phys Chem B 2023; 127:8669-8680. [PMID: 37781882 DOI: 10.1021/acs.jpcb.3c03938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Molten salt electrochemistry has been widely used in many fields, especially for metal extraction/refinement. The understanding of mass transfer in molten salts under harsh operation conditions is of great importance to reveal reaction mechanisms and advance fine technologies. It has been generally assumed that natural convection is negligible in stagnant molten salt electrochemistry. Herein, we report an abnormal natural convection in molten LiCl-KCl, with the arising time from 2.37 s at 873 K to 10.13 s at 673 K. Using the concentration correction factor, the derived thickness of the natural convection-diffusion layer (δconv.) was found to be ranging from 128 to 163 μm, much thinner than those in aqueous solutions (∼200 μm). The simulations showed that the notable natural convection resulted from convection-diffusion layer (CDL) convection dominated over the density-driven convection even at high redox concentrations, implying the severe vibration of molten salt systems. To suppress the intense natural convection, we predicted that the use of microelectrodes (with radii less than 23.2 μm for δconv. = 150 μm) would be a promising tool, regardless of their inferior stabilities in high-temperature molten salts at this stage. These innovative findings offer insights into the impact of natural convection on mass transfer in molten salts that have not been previously revealed.
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Affiliation(s)
- Jianbang Ge
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China
| | - Biwu Cai
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China
| | - Fei Zhu
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China
| | - Yang Gao
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China
| | - Xinrui Wang
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China
| | - Qianjin Chen
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering, Donghua University, Shanghai 201620, China
| | - Mingyong Wang
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China
| | - Shuqiang Jiao
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China
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3
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Linden M, Hofmann S, Herman A, Ehler N, Bär RM, Waldvogel SR. Electrochemical Synthesis of Pyrazolines and Pyrazoles via [3+2] Dipolar Cycloaddition. Angew Chem Int Ed Engl 2023; 62:e202214820. [PMID: 36478106 DOI: 10.1002/anie.202214820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 12/06/2022] [Accepted: 12/06/2022] [Indexed: 12/12/2022]
Abstract
Pyrazolines and pyrazoles are common and important motifs of pharmaceutical agents and agrochemicals. Herein, the first electrochemical approach for their direct synthesis from easily accessible hydrazones and dipolarophiles up to decagram scale is presented. The application of a biphasic system (aqueous/organic) even allows for the conversion of highly sensitive alkenes, wherein inexpensive sodium iodide is employed in a dual role as supporting electrolyte and mediator. In addition, mechanistic insight into the reaction is given by the isolation of key step intermediates. The relevance of the presented reaction is underlined by the synthesis of commercial herbicide safener mefenpyr-diethyl in good yields.
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Affiliation(s)
- Martin Linden
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Silja Hofmann
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Antonia Herman
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Nicole Ehler
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Robin M Bär
- Research & Development, Crop Science, Bayer AG, Alfred-Nobel-Str. 50, 40789, Monheim am Rhein, Germany
| | - Siegfried R Waldvogel
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
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4
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Klein M, Waldvogel SR. Counter Electrode Reactions-Important Stumbling Blocks on the Way to a Working Electro-organic Synthesis. Angew Chem Int Ed Engl 2022; 61:e202204140. [PMID: 35668714 PMCID: PMC9828107 DOI: 10.1002/anie.202204140] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Indexed: 01/12/2023]
Abstract
Over the past two decades, electro-organic synthesis has gained significant interest, both in technical and academic research as well as in terms of applications. The omission of stoichiometric oxidizers or reducing agents enables a more sustainable route for redox reactions in organic chemistry. Even if it is well-known that every electrochemical oxidation is only viable with an associated reduction reaction and vice versa, the relevance of the counter reaction is often less addressed. In this Review, the importance of the corresponding counter reaction in electro-organic synthesis is highlighted and how it can affect the performance and selectivity of the electrolytic conversion. A selection of common strategies and unique concepts to tackle this issue are surveyed to provide a guide to select appropriate counter reactions for electro-organic synthesis.
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Affiliation(s)
- Martin Klein
- Department of ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128MainzGermany
| | - Siegfried R. Waldvogel
- Department of ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128MainzGermany
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5
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Pellumbi K, Wickert L, Kleinhaus JT, Wolf J, Leonard A, Tetzlaff D, Goy R, Medlock JA, Junge Puring K, Cao R, Siegmund D, Apfel UP. Opening the pathway towards a scalable electrochemical semi-hydrogenation of alkynols via earth-abundant metal chalcogenides. Chem Sci 2022; 13:12461-12468. [PMID: 36382291 PMCID: PMC9629083 DOI: 10.1039/d2sc04647d] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 10/06/2022] [Indexed: 09/16/2023] Open
Abstract
Electrosynthetic methods are crucial for a future sustainable transformation of the chemical industry. Being an integral part of many synthetic pathways, the electrification of hydrogenation reactions gained increasing interest in recent years. However, for the large-scale industrial application of electrochemical hydrogenations, low-resistance zero-gap electrolysers operating at high current densities and high substrate concentrations, ideally applying noble-metal-free catalyst systems, are required. Because of their conductivity, stability, and stoichiometric flexibility, transition metal sulfides of the pentlandite group have been thoroughly investigated as promising electrocatalysts for electrochemical applications but were not investigated for electrochemical hydrogenations of organic materials. An initial screening of a series of first row transition metal pentlandites revealed promising activity for the electrochemical hydrogenation of alkynols in water. The most active catalyst within the series was then incorporated into a zero-gap electrolyser enabling the hydrogenation of alkynols at current densities of up to 240 mA cm-2, Faraday efficiencies of up to 75%, and an alkene selectivity of up to 90%. In this scalable setup we demonstrate high stability of catalyst and electrode for at least 100 h. Altogether, we illustrate the successful integration of a sustainable catalyst into a scalable zero-gap electrolyser establishing electrosynthetic methods in an application-oriented manner.
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Affiliation(s)
- Kevinjeorjios Pellumbi
- Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT Osterfelder Straße 3 D-46047 Oberhausen Germany
- Inorganic Chemistry I, Ruhr University Bochum Universitätsstraße 150 D-44780 Bochum Germany
| | - Leon Wickert
- Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT Osterfelder Straße 3 D-46047 Oberhausen Germany
- Inorganic Chemistry I, Ruhr University Bochum Universitätsstraße 150 D-44780 Bochum Germany
| | - Julian T Kleinhaus
- Inorganic Chemistry I, Ruhr University Bochum Universitätsstraße 150 D-44780 Bochum Germany
| | - Jonas Wolf
- Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT Osterfelder Straße 3 D-46047 Oberhausen Germany
- Inorganic Chemistry I, Ruhr University Bochum Universitätsstraße 150 D-44780 Bochum Germany
| | - Allison Leonard
- Inorganic Chemistry I, Ruhr University Bochum Universitätsstraße 150 D-44780 Bochum Germany
| | - David Tetzlaff
- Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT Osterfelder Straße 3 D-46047 Oberhausen Germany
- Inorganic Chemistry I, Ruhr University Bochum Universitätsstraße 150 D-44780 Bochum Germany
| | - Roman Goy
- DSM Nutritional Products AG Wurmisweg 576 CH-4303 Kaiseraugst Switzerland
| | - Jonathan A Medlock
- DSM Nutritional Products AG Wurmisweg 576 CH-4303 Kaiseraugst Switzerland
| | - Kai Junge Puring
- Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT Osterfelder Straße 3 D-46047 Oberhausen Germany
| | - Rui Cao
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University Xi'an 710119 China
| | - Daniel Siegmund
- Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT Osterfelder Straße 3 D-46047 Oberhausen Germany
- Inorganic Chemistry I, Ruhr University Bochum Universitätsstraße 150 D-44780 Bochum Germany
| | - Ulf-Peter Apfel
- Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT Osterfelder Straße 3 D-46047 Oberhausen Germany
- Inorganic Chemistry I, Ruhr University Bochum Universitätsstraße 150 D-44780 Bochum Germany
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6
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Wu J, Kozlowski MC. Catalytic Oxidative Coupling of Phenols and Related Compounds. ACS Catal 2022; 12:6532-6549. [DOI: 10.1021/acscatal.2c00318] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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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7
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Pollok D, Rausch FU, Beil SB, Franzmann P, Waldvogel SR. Allocolchicines─Synthesis with Electro-organic Key Transformations. Org Lett 2022; 24:3760-3765. [PMID: 35503929 DOI: 10.1021/acs.orglett.2c01084] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The naturally occurring colchicine and allocolchicines in the meadow saffron are potentially active ingredients for cancer therapy. A concise protocol for the sustainable synthesis of allocolchicines using up to two electro-organic key transformations is demonstrated. This straightforward synthesis of N-acetylcolchinol methyl ether in a five-step protocol was adopted using protecting groups to enable access to N-acetylcolchinol and the phosphate derivative ZD6126.
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Affiliation(s)
- Dennis Pollok
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Florian U Rausch
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Sebastian B Beil
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Peter Franzmann
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Siegfried R Waldvogel
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
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8
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Alvarado JIM, Meinhardt JM, Lin S. Working at the interfaces of data science and synthetic electrochemistry. TETRAHEDRON CHEM 2022; 1. [PMID: 35441154 PMCID: PMC9014485 DOI: 10.1016/j.tchem.2022.100012] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electrochemistry is quickly entering the mainstream of synthetic organic chemistry. The diversity of new transformations enabled by electrochemistry is to a large extent a consequence of the unique features and reaction parameters in electrochemical systems including redox mediators, applied potential, electrode material, and cell construction. While offering chemists new means to control reactivity and selectivity, these additional features also increase the dimensionalities of a reaction system and complicate its optimization. This challenge, however, has spawned increasing adoption of data science tools to aid reaction discovery as well as development of high-throughput screening platforms that facilitate the generation of high quality datasets. In this Perspective, we provide an overview of recent advances in data-science driven electrochemistry with an emphasis on the opportunities and challenges facing this growing subdiscipline.
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9
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Baidya M, Maiti D, Roy L, De Sarkar S. Trifluoroethanol as a Unique Additive for the Chemoselective Electrooxidation of Enamines to Access Unsymmetrically Substituted NH‐Pyrroles. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202111679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Mrinmay Baidya
- Department of Chemical Sciences Indian Institute of Science Education and Research Kolkata Mohanpur 741246 West Bengal India
| | - Debabrata Maiti
- Department of Chemical Sciences Indian Institute of Science Education and Research Kolkata Mohanpur 741246 West Bengal India
| | - Lisa Roy
- Institute of Chemical Technology Mumbai IOC Odisha Campus Bhubaneswar IIT Kharagpur Extension Centre Bhubaneswar 751013 India
| | - Suman De Sarkar
- Department of Chemical Sciences Indian Institute of Science Education and Research Kolkata Mohanpur 741246 West Bengal India
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10
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Schotten C, Manson J, Chamberlain TW, Bourne RA, Nguyen BN, Kapur N, Willans CE. Development of a multistep, electrochemical flow platform for automated catalyst screening. Catal Sci Technol 2022. [DOI: 10.1039/d2cy00587e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An integrated flow platform enables the electrochemical synthesis of base-metal catalysts with high-throughput screening and rapid data generation.
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Affiliation(s)
| | - Jamie Manson
- School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
| | | | - Richard A. Bourne
- School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
- School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, UK
| | - Bao N. Nguyen
- School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
- School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, UK
| | - Nik Kapur
- School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT, UK
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11
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Bieniek JC, Grünewald M, Winter J, Schollmeyer D, Waldvogel SR. Electrochemical Synthesis of
N
,
N
’‑ Disubstituted Indazolin-3-ones via Intramolecular Anodic DehydrogenativeN-NCoupling Reaction. Chem Sci 2022; 13:8180-8186. [PMID: 35919432 PMCID: PMC9278119 DOI: 10.1039/d2sc01827f] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 06/10/2022] [Indexed: 11/30/2022] Open
Abstract
The use of electricity as a traceless oxidant enables a sustainable and novel approach to N,N′-disubstituted indazolin-3-ones by an intramolecular anodic dehydrogenative N–N coupling reaction. This method is characterized by mild reaction conditions, an easy experimental setup, excellent scalability, and a high atom economy. It was used to synthesize various indazolin-3-one derivatives in yields up to 78%, applying inexpensive and sustainable electrode materials and a low supporting electrolyte concentration. Mechanistic studies, based on cyclic voltammetry experiments, revealed a biradical pathway. Furthermore, the access to single 2-aryl substituted indazolin-3-ones by cleavage of the protecting group could be demonstrated. A novel sustainable electrochemical synthetic route to N,N′-disubstituted indazolin-3-ones by direct anodic oxidation with mild reaction conditions, a simple galvanostatic setup, broad scope and excellent scalability is established.![]()
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Affiliation(s)
- Jessica C Bieniek
- Department of Chemistry, Johannes Gutenberg University Duesbergweg 10-14 Mainz 55128 Germany https://www.aksw.uni-mainz.de/
| | - Michele Grünewald
- Department of Chemistry, Johannes Gutenberg University Duesbergweg 10-14 Mainz 55128 Germany https://www.aksw.uni-mainz.de/
| | - Johannes Winter
- Department of Chemistry, Johannes Gutenberg University Duesbergweg 10-14 Mainz 55128 Germany https://www.aksw.uni-mainz.de/
| | - Dieter Schollmeyer
- Department of Chemistry, Johannes Gutenberg University Duesbergweg 10-14 Mainz 55128 Germany https://www.aksw.uni-mainz.de/
| | - Siegfried R Waldvogel
- Department of Chemistry, Johannes Gutenberg University Duesbergweg 10-14 Mainz 55128 Germany https://www.aksw.uni-mainz.de/
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12
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Seidler J, Bernhard R, Haufe S, Neff C, Gärtner T, Waldvogel SR. From Screening to Scale-Up: The DoE-Based Optimization of Electrochemical Reduction of l-Cystine at Metal Cathodes. Org Process Res Dev 2021. [DOI: 10.1021/acs.oprd.1c00153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Johannes Seidler
- ESy-Labs GmbH, Siemensstraße 7, 93055 Regensburg, Germany
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Rebecca Bernhard
- Wacker Chemie AG, Consortium für elektrochemische Industrie, Zielstattstraße 20, 81379 München, Germany
| | - Stefan Haufe
- Wacker Chemie AG, Consortium für elektrochemische Industrie, Zielstattstraße 20, 81379 München, Germany
| | - Caroline Neff
- ESy-Labs GmbH, Siemensstraße 7, 93055 Regensburg, Germany
| | - Tobias Gärtner
- ESy-Labs GmbH, Siemensstraße 7, 93055 Regensburg, Germany
| | - Siegfried R. Waldvogel
- ESy-Labs GmbH, Siemensstraße 7, 93055 Regensburg, Germany
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
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13
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Baidya M, Maiti D, Roy L, De Sarkar S. Trifluoroethanol as a Unique Additive for the Chemoselective Electrooxidation of Enamines to Access Unsymmetrically Substituted NH-Pyrroles. Angew Chem Int Ed Engl 2021; 61:e202111679. [PMID: 34851544 DOI: 10.1002/anie.202111679] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 11/15/2021] [Indexed: 01/31/2023]
Abstract
An electrochemical method for the synthesis of unsymmetrically substituted NH-pyrroles is described. The synthetic strategy comprises a challenging heterocoupling between two structurally diverse enamines via sequential chemoselective oxidation, addition, and cyclization processes. A series of aryl- and alkyl-substituted enamines were effectively cross-coupled from an equimolar mixture to synthesize various unsymmetrical pyrrole derivatives up to 84 % yield. The desired cross-coupling was achieved by tuning the oxidation potential of the enamines by utilizing a "magic effect" of the additive trifluoroethanol (TFE). Additionally, extensive computational studies reveal the unique role of TFE in promoting the heterocoupling process by regulating the activation energies of the reaction steps through H-bonding and C-H⋅⋅⋅π interactions. Importantly, the developed electrochemical protocol was found to be equally efficient for the homocoupling of enamines to form symmetric pyrroles up to 92 % yield.
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Affiliation(s)
- Mrinmay Baidya
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, West Bengal, India
| | - Debabrata Maiti
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, West Bengal, India
| | - Lisa Roy
- Institute of Chemical Technology Mumbai, IOC Odisha Campus Bhubaneswar, IIT Kharagpur Extension Centre, Bhubaneswar, 751013, India
| | - Suman De Sarkar
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, West Bengal, India
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14
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Guo B, Xu HC. Electrocatalytic C(sp 3)-H/C(sp)-H cross-coupling in continuous flow through TEMPO/copper relay catalysis. Beilstein J Org Chem 2021; 17:2650-2656. [PMID: 34795802 PMCID: PMC8561139 DOI: 10.3762/bjoc.17.178] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 10/21/2021] [Indexed: 12/17/2022] Open
Abstract
Electrocatalytic dehydrogenative C(sp3)-H/C(sp)-H cross-coupling of tetrahydroisoquinolines with terminal alkynes has been achieved in a continuous-flow microreactor through 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)/copper relay catalysis. The reaction is easily scalable and requires low concentration of supporting electrolyte and no external chemical oxidants or ligands, providing straightforward and sustainable access to 2-functionalized tetrahydroisoquinolines.
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Affiliation(s)
- Bin Guo
- Key Laboratory of Chemical Biology of Fujian Province and College of Chemistry and Chemical Engineering, Xiamen University, People’s Republic of China
| | - Hai-Chao Xu
- Key Laboratory of Chemical Biology of Fujian Province and College of Chemistry and Chemical Engineering, Xiamen University, People’s Republic of China
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15
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Li L, Kail S, Weber SM, Hilt G. Indium‐katalysierte Transferhydrierung zur reduktiven Cyclisierung von 2‐Alkinylenonen zu trisubstituierten Furanen. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202109266] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Luomo Li
- Institut für Chemie Carl von Ossietzky Universität Oldenburg Carl-von-Ossietzky-Straße 9–11 26111 Oldenburg Deutschland
| | - Sascha Kail
- Institut für Chemie Carl von Ossietzky Universität Oldenburg Carl-von-Ossietzky-Straße 9–11 26111 Oldenburg Deutschland
| | - Sebastian M. Weber
- Institut für Chemie Carl von Ossietzky Universität Oldenburg Carl-von-Ossietzky-Straße 9–11 26111 Oldenburg Deutschland
| | - Gerhard Hilt
- Institut für Chemie Carl von Ossietzky Universität Oldenburg Carl-von-Ossietzky-Straße 9–11 26111 Oldenburg Deutschland
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16
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Li L, Kail S, Weber SM, Hilt G. Indium-Catalysed Transfer Hydrogenation for the Reductive Cyclisation of 2-Alkynyl Enones towards Trisubstituted Furans. Angew Chem Int Ed Engl 2021; 60:23661-23666. [PMID: 34476880 PMCID: PMC8597135 DOI: 10.1002/anie.202109266] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/23/2021] [Indexed: 01/04/2023]
Abstract
Indium tribromide catalysed the transfer hydrogenation from dihydroaromatic compounds, such as the commercially available γ-terpinene, to enones, which resulted in the cyclisation to trisubstituted furan derivatives. The reaction was initiated by a Michael addition of a hydride nucleophile to the enone subunit followed by a Lewis-acid-assisted cyclisation and the formation of a furan-indium intermediate and a Wheland intermediate derived from the dihydroaromatic starting material. The product was formed by protonation from the Wheland complex and replaced the indium tribromide substituent. In addition, a site-specific deuterium labelling of the dihydroaromatic HD surrogates resulted in site specific labelling of the products and gave useful insights into the reaction mechanism by H-D scrambling.
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Affiliation(s)
- Luomo Li
- Institut für ChemieCarl von Ossietzky Universität OldenburgCarl-von-Ossietzky-Strasse 9–1126111OldenburgGermany
| | - Sascha Kail
- Institut für ChemieCarl von Ossietzky Universität OldenburgCarl-von-Ossietzky-Strasse 9–1126111OldenburgGermany
| | - Sebastian M. Weber
- Institut für ChemieCarl von Ossietzky Universität OldenburgCarl-von-Ossietzky-Strasse 9–1126111OldenburgGermany
| | - Gerhard Hilt
- Institut für ChemieCarl von Ossietzky Universität OldenburgCarl-von-Ossietzky-Strasse 9–1126111OldenburgGermany
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Hielscher M, Oehl EK, Gleede B, Buchholz J, Waldvogel SR. Optimization Strategies for the Anodic Phenol‐Arene Cross‐Coupling Reaction. ChemElectroChem 2021. [DOI: 10.1002/celc.202101226] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Maximilian Hielscher
- Department of Chemistry Johannes Gutenberg University Duesbergweg 10–14 55128 Mainz Germany
| | - Elisabeth K. Oehl
- Department of Chemistry Johannes Gutenberg University Duesbergweg 10–14 55128 Mainz Germany
| | - Barbara Gleede
- Department of Chemistry Johannes Gutenberg University Duesbergweg 10–14 55128 Mainz Germany
| | - Julian Buchholz
- Department of Chemistry Johannes Gutenberg University Duesbergweg 10–14 55128 Mainz Germany
| | - Siegfried R. Waldvogel
- Department of Chemistry Johannes Gutenberg University Duesbergweg 10–14 55128 Mainz Germany
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18
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Fährmann J, Hilt G. Wechselstromelektrolyse als effizientes Instrument für die direkte elektrochemische Oxidation von Hydroxamsäuren für die Acyl‐Nitroso Diels‐Alder‐Reaktion. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107148] [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)
- Jan Fährmann
- Institut für Chemie Universität Oldenburg Carl-von-Ossietzky-Straße 9–11 26111 Oldenburg Deutschland
| | - Gerhard Hilt
- Institut für Chemie Universität Oldenburg Carl-von-Ossietzky-Straße 9–11 26111 Oldenburg Deutschland
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19
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Fährmann J, Hilt G. Alternating Current Electrolysis as Efficient Tool for the Direct Electrochemical Oxidation of Hydroxamic Acids for Acyl Nitroso Diels-Alder Reactions. Angew Chem Int Ed Engl 2021; 60:20313-20317. [PMID: 34232547 PMCID: PMC8456936 DOI: 10.1002/anie.202107148] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Indexed: 01/15/2023]
Abstract
The acyl nitroso Diels-Alder reaction of 1,3-dienes with electrochemically oxidised hydroxamic acids is described. By using alternating current electrolysis, their typical electro-induced decomposition could be suppressed in favour of the 1,2-oxazine cycloaddition products. The reaction was optimised using Design of Experiments (DoE) and a sensitivity test was conducted. A mixture of triethylamine/hexafluoroisopropanol served as supporting electrolyte in dichloromethane, thus giving products of high purity after evaporation of the volatiles without further purification. The optimised reaction conditions were applied to various 1,3-dienes and hydroxamic acids, giving up to 96 % isolated yield.
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Affiliation(s)
- Jan Fährmann
- Institut für ChemieUniversität OldenburgCarl-von-Ossietzky-Straße 9–1126111OldenburgGermany
| | - Gerhard Hilt
- Institut für ChemieUniversität OldenburgCarl-von-Ossietzky-Straße 9–1126111OldenburgGermany
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Dörr M, Hielscher MM, Proppe J, Waldvogel SR. Electrosynthetic Screening and Modern Optimization Strategies for Electrosynthesis of Highly Value‐added Products. ChemElectroChem 2021. [DOI: 10.1002/celc.202100318] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Maurice Dörr
- Department of Chemistry Johannes Gutenberg University Duesbergweg 10–14 55128 Mainz Germany
| | | | - Jonny Proppe
- Institute of Physical Chemistry Georg-August Universität Tammannstr. 6 37077 Göttingen Germany
| | - Siegfried R. Waldvogel
- Department of Chemistry Johannes Gutenberg University Duesbergweg 10–14 55128 Mainz Germany
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