1
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Leng BL, Lin X, Chen JS, Li XH. Electrocatalytic water-to-oxygenates conversion: redox-mediated versus direct oxygen transfer. Chem Commun (Camb) 2024; 60:7523-7534. [PMID: 38957004 DOI: 10.1039/d4cc01960a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
Electrocatalytic oxygenation of hydrocarbons with high selectivity has attracted much attention for its advantages in the sustainable and controllable production of oxygenated compounds with reduced greenhouse gas emissions. Especially when utilizing water as an oxygen source, by constructing a water-to-oxygenates conversion system at the anode, the environment and/or energy costs of producing oxygenated compounds and hydrogen energy can be significantly reduced. There is a broad consensus that the generation and transformation of oxygen species are among the decisive factors determining the overall efficiency of oxygenation reactions. Thus, it is necessary to elucidate the oxygen transfer process to suggest more efficient strategies for electrocatalytic oxygenation. Herein, we introduce oxygen transfer routes through redox-mediated pathways or direct oxygen transfer methods. Especially for the scarcely investigated direct oxygen transfer at the anode, we aim to detail the strategies of catalyst design targeting the efficient oxygen transfer process including activation of organic substrate, generation/adsorption of oxygen species, and transformation of oxygen species for oxygenated compounds. Based on these examples, the significance of balancing the generation and transformation of oxygen species, tuning the states of organic substrates and intermediates, and accelerating electron transfer for organic activation for direct oxygen transfer has been elucidated. Moreover, greener organic synthesis routes through heteroatom transfer and molecular fragment transfer are anticipated beyond oxygen transfer.
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Affiliation(s)
- Bing-Liang Leng
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China.
| | - Xiu Lin
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China.
| | - Jie-Sheng Chen
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China.
| | - Xin-Hao Li
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China.
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2
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Fang X, Zeng Y, Huang Y, Zhu Z, Lin S, Xu W, Zheng C, Hu X, Qiu Y, Ruan Z. Electrochemical synthesis of peptide aldehydes via C‒N bond cleavage of cyclic amines. Nat Commun 2024; 15:5181. [PMID: 38890290 PMCID: PMC11189564 DOI: 10.1038/s41467-024-49223-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 05/29/2024] [Indexed: 06/20/2024] Open
Abstract
Peptide aldehydes are crucial biomolecules essential to various biological systems, driving a continuous demand for efficient synthesis methods. Herein, we develop a metal-free, facile, and biocompatible strategy for direct electrochemical synthesis of unnatural peptide aldehydes. This electro-oxidative approach enabled a step- and atom-economical ring-opening via C‒N bond cleavage, allowing for homoproline-specific peptide diversification and expansion of substrate scope to include amides, esters, and cyclic amines of various sizes. The remarkable efficacy of the electro-synthetic protocol set the stage for the efficient modification and assembly of linear and macrocyclic peptides using a concise synthetic sequence with racemization-free conditions. Moreover, the combination of experiments and density functional theory (DFT) calculations indicates that different N-acyl groups play a decisive role in the reaction activity.
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Affiliation(s)
- Xinyue Fang
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, PR China
| | - Yong Zeng
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, PR China
| | - Yawen Huang
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, PR China
| | - Zile Zhu
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, PR China
| | - Shengsheng Lin
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, PR China
| | - Wenyan Xu
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, PR China
| | - Chengwei Zheng
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, PR China
| | - Xinwei Hu
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, PR China.
| | - Youai Qiu
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, PR China.
| | - Zhixiong Ruan
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, PR China.
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3
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Liu C, Liu Y, Yang S, Zheng B, Zhang Y. Electrochemical Lactonization Enabled by Unusual Shono-Type Oxidation from Functionalized Benzoic Acids. Org Lett 2024; 26:1936-1940. [PMID: 38407049 DOI: 10.1021/acs.orglett.4c00318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
A novel method for electrochemical lactonization via C(sp3)-H functionalization was developed. This metal- and oxidant-free strategy enabled the efficient synthesis of various lactones. Gram-scale reaction and derivatization of the lactone product demonstrated the synthetic utility of this methodology. Mechanistic studies using control experiments and CV curves elucidated the proposed intramolecular HAT and the oxidative cyclization pathway. An unusual Shono-type oxidation was realized through this electrochemical approach, proceeding without a traditional nucleophilic addition process.
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Affiliation(s)
- Chen Liu
- College of Science, China Agricultural University, Beijing 100193, P. R. China
| | - Yunge Liu
- College of Science, China Agricultural University, Beijing 100193, P. R. China
| | - Shurui Yang
- College of Science, China Agricultural University, Beijing 100193, P. R. China
| | - Bing Zheng
- College of Science, China Agricultural University, Beijing 100193, P. R. China
| | - Yunfei Zhang
- College of Science, China Agricultural University, Beijing 100193, P. R. China
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4
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Rafiee M, Abrams DJ, Cardinale L, Goss Z, Romero-Arenas A, Stahl SS. Cyclic voltammetry and chronoamperometry: mechanistic tools for organic electrosynthesis. Chem Soc Rev 2024; 53:566-585. [PMID: 38050749 PMCID: PMC10842901 DOI: 10.1039/d2cs00706a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2023]
Abstract
Electrochemical methods offer unique advantages for chemical synthesis, as the reaction selectivity may be controlled by tuning the applied potential or current. Similarly, measuring the current or potential during the reaction can provide valuable mechanistic insights into these reactions. The aim of this tutorial review is to explain the use of cyclic voltammetry and chronoamperometry to interrogate reaction mechanisms, optimize electrochemical reactions, or design new reactions. Fundamental principles of cyclic voltammetry and chronoamperometry experiments are presented together with the application of these techniques to probe (electro)chemical reactions. Several diagnostic criteria are noted for the use of cyclic voltammetry and chronoamperometry to analyze coupled electrochemical-chemical (EC) reactions, and a series of individual mechanistic studies are presented. Steady state voltammetric and amperometric measurements, using microelectrodes (ME) or rotating disk electrodes (RDE) provide a means to analyze concentrations of redox active species in bulk solution and offer a versatile strategy to conduct kinetic analysis or determine the species present during (electro)synthetic chemical reactions.
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Affiliation(s)
- Mohammad Rafiee
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, Missouri 64110, USA.
| | - Dylan J Abrams
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Luana Cardinale
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Zachary Goss
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, Missouri 64110, USA.
| | - Antonio Romero-Arenas
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
- Departamento de Química Orgánica, Universidad de Sevilla, C/Prof. García González, 1, 41012 Sevilla, Spain
| | - Shannon S Stahl
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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5
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Rodrigo S, Hazra A, Mahajan JP, Nguyen HM, Luo L. Overcoming the Potential Window-Limited Functional Group Compatibility by Alternating Current Electrolysis. J Am Chem Soc 2023; 145:21851-21859. [PMID: 37747918 PMCID: PMC10774024 DOI: 10.1021/jacs.3c05802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
The functional group compatibility of an electrosynthetic method is typically limited by its potential reaction window. Here, we report that alternating current (AC) electrolysis can overcome such potential window-limited functional group compatibility. Using alkene heterodifunctionalization as a model system, we design and demonstrate a series of AC-driven reactions that add two functional groups sequentially and separately under the cathodic and anodic pulses, including chloro- and bromotrilfuoromethylation as well as chlorosulfonylation. We discovered that the oscillating redox environment during AC electrolysis allows the regeneration of the redox-active functional groups after their oxidation or reduction in the preceding step. As a result, even though redox labile functional groups such as pyrrole, quinone, and aryl thioether fall in the reaction potential window, they are tolerated under AC electrolysis conditions, leading to synthetically useful yields. The cyclic voltammetric study has confirmed that the product yield is limited by the extent of starting material regeneration during the redox cycling. Our findings open a new avenue for improving functional group compatibility in electrosynthesis and show the possibility of predicting the product yield under AC electrolysis from voltammogram features.
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Affiliation(s)
- Sachini Rodrigo
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Atanu Hazra
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Jyoti P Mahajan
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Hien M Nguyen
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Long Luo
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
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6
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Chang Z, Wang S, Huang J, Chen G, Tang Z, Wang R, Zhao D. Copper catalyzed Shono-type oxidation of proline residues in peptide. SCIENCE ADVANCES 2023; 9:eadj3090. [PMID: 37703373 PMCID: PMC10881060 DOI: 10.1126/sciadv.adj3090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 08/11/2023] [Indexed: 09/15/2023]
Abstract
Since the initial report in 1975, the Shono oxidation has become a powerful tool to functionalize the α position of amines, including proline derivatives, by electrochemical oxidation. However, the application of electrochemical Shono oxidations is restricted to the preparation of simple building blocks and homogeneous Shono-type oxidation of proline derivatives remains challenging. The late-stage functionalization at proline residues embedded within peptides is highly important as substitutions about the proline ring are known to affect biological and pharmacological activities. Here, we show that homogenous copper-catalyzed oxidation conditions complement the Shono oxidation and this general protocol can be applied to a series of formal C-C coupling reactions with a variety of nucleophiles using a one-pot procedure. This protocol shows good tolerance toward 19 proteinogenic amino acids and was used to functionalize several representative bioactive peptides, including captopril, enalapril, Smac, and endomorphin-2. Last, peptide cyclization can also be achieved by using an appropriately positioned side-chain hydroxyl moiety.
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Affiliation(s)
- Zhe Chang
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Si Wang
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jialin Huang
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Geshuyi Chen
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Zhanyong Tang
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Rui Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Depeng Zhao
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
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7
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Abstract
Nitroxides, also known as nitroxyl radicals, are long-lived or stable radicals with the general structure R1R2N-O•. The spin distribution over the nitroxide N and O atoms contributes to the thermodynamic stability of these radicals. The presence of bulky N-substituents R1 and R2 prevents nitroxide radical dimerization, ensuring their kinetic stability. Despite their reactivity toward various transient C radicals, some nitroxides can be easily stored under air at room temperature. Furthermore, nitroxides can be oxidized to oxoammonium salts (R1R2N═O+) or reduced to anions (R1R2N-O-), enabling them to act as valuable oxidants or reductants depending on their oxidation state. Therefore, they exhibit interesting reactivity across all three oxidation states. Due to these fascinating properties, nitroxides find extensive applications in diverse fields such as biochemistry, medicinal chemistry, materials science, and organic synthesis. This review focuses on the versatile applications of nitroxides in organic synthesis. For their use in other important fields, we will refer to several review articles. The introductory part provides a brief overview of the history of nitroxide chemistry. Subsequently, the key methods for preparing nitroxides are discussed, followed by an examination of their structural diversity and physical properties. The main portion of this review is dedicated to oxidation reactions, wherein parent nitroxides or their corresponding oxoammonium salts serve as active species. It will be demonstrated that various functional groups (such as alcohols, amines, enolates, and alkanes among others) can be efficiently oxidized. These oxidations can be carried out using nitroxides as catalysts in combination with various stoichiometric terminal oxidants. By reducing nitroxides to their corresponding anions, they become effective reducing reagents with intriguing applications in organic synthesis. Nitroxides possess the ability to selectively react with transient radicals, making them useful for terminating radical cascade reactions by forming alkoxyamines. Depending on their structure, alkoxyamines exhibit weak C-O bonds, allowing for the thermal generation of C radicals through reversible C-O bond cleavage. Such thermally generated C radicals can participate in various radical transformations, as discussed toward the end of this review. Furthermore, the application of this strategy in natural product synthesis will be presented.
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Affiliation(s)
- Dirk Leifert
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
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8
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Weierbach SM, Reynolds RP, Stephens SM, Vlasakakis KV, Ritter RT, White OM, Patel NH, Hayes EC, Dunmire S, Lambert KM. Chemoselective Oxidation of Thiols with Oxoammonium Cations. J Org Chem 2023; 88:11392-11410. [PMID: 35926190 DOI: 10.1021/acs.joc.2c01097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The oxidation of various aryl and aliphatic thiols with the commercially available and environmentally benign reagent Bobbitt's salt (1) has been investigated. The reaction affords the corresponding disulfide products in good to excellent yields (71-99%) and can be accomplished in water, methanol, or acetonitrile solvent. Moreover, the process is highly chemoselective, tolerating traditionally oxidation-labile groups such as free amines and alcohols. Combined experimental and computational studies reveal that the oxidation takes place via a polar two-electron process with concomitant and unexpected deoxygenation of the oxoammonium cation through homolysis of the weak N-O bond, differing from prototypical radical-based thiol couplings. This unusual consumption of the oxidant has significant implications for the development of new nitroxide-based radical traps for probing S-centered radicals, the advancement of new electrochemical or catalytic processes involving nitroxide/oxoammonium salt redox couples, and applications to biological systems.
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Affiliation(s)
- Shayne M Weierbach
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Robert P Reynolds
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Shannon M Stephens
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Kostantinos V Vlasakakis
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Ramsey T Ritter
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Olivia M White
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Nishi H Patel
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Eric C Hayes
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Sydney Dunmire
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Kyle M Lambert
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States
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9
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Hatch CE, Chain WJ. Electrochemically Enabled Total Syntheses of Natural Products. ChemElectroChem 2023; 10:e202300140. [PMID: 38106361 PMCID: PMC10723087 DOI: 10.1002/celc.202300140] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Indexed: 12/19/2023]
Abstract
Electrochemical techniques have helped to enable the total synthesis of natural products since the pioneering work of Kolbe in the mid 1800's. The electrochemical toolset grows every day and these new possibilities change the way chemists look at and think about natural products. This review provides a perspective on total syntheses wherein electrochemical techniques enabled the carbon─carbon bond formations in the skeletal assembly of important natural products, discussion of mechanistic details, and representative examples of the bond formations enabled over the last several decades. These bond formations are often distinctly different from those possible with conventional chemistries and allow assemblies complementary to other techniques.
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Affiliation(s)
- Chad E Hatch
- Chemical Biology, Memorial Sloan Kettering Cancer Center, 417 E. 68 St., New York, NY, 10065 (United States)
| | - William J Chain
- Department of Chemistry & Biochemistry, University of Delaware, 163 The Green, Newark, DE, 19716 (United States)
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10
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Rein J, Rozema SD, Langner OC, Zacate SB, Hardy MA, Siu JC, Mercado BQ, Sigman MS, Miller SJ, Lin S. Generality-oriented optimization of enantioselective aminoxyl radical catalysis. Science 2023; 380:706-712. [PMID: 37200427 PMCID: PMC10277815 DOI: 10.1126/science.adf6177] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 03/29/2023] [Indexed: 05/20/2023]
Abstract
Catalytic enantioselective methods that are generally applicable to a broad range of substrates are rare. We report a strategy for the oxidative desymmetrization of meso-diols predicated on a nontraditional catalyst optimization protocol by using a panel of screening substrates rather than a singular model substrate. Critical to this approach was rational modulation of a peptide sequence in the catalyst incorporating a distinct aminoxyl-based active residue. A general catalyst emerged, providing high selectivity in the delivery of enantioenriched lactones across a broad range of diols, while also achieving up to ~100,000 turnovers.
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Affiliation(s)
- J. Rein
- Department of Chemistry and Chemical Biology, Cornell University; Ithaca, NY 14853, USA
| | - S. D. Rozema
- Department of Chemistry, Yale University; 225 Prospect Street, New Haven, CT 06520, USA
| | - O. C. Langner
- Department of Chemistry, Yale University; 225 Prospect Street, New Haven, CT 06520, USA
| | - S. B. Zacate
- Department of Chemistry and Chemical Biology, Cornell University; Ithaca, NY 14853, USA
| | - M. A. Hardy
- Department of Chemistry, University of Utah; 315 South 1400 East, Salt Lake City, UT 84112, USA
| | - J. C. Siu
- Department of Chemistry and Chemical Biology, Cornell University; Ithaca, NY 14853, USA
| | - B. Q. Mercado
- Department of Chemistry, Yale University; 225 Prospect Street, New Haven, CT 06520, USA
| | - M. S. Sigman
- Department of Chemistry, University of Utah; 315 South 1400 East, Salt Lake City, UT 84112, USA
| | - S. J. Miller
- Department of Chemistry, Yale University; 225 Prospect Street, New Haven, CT 06520, USA
| | - S. Lin
- Department of Chemistry and Chemical Biology, Cornell University; Ithaca, NY 14853, USA
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11
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Luo MJ, Zhou W, Yang R, Ding H, Song XR, Xiao Q. Electrochemically enabled decyanative C(sp 3)-H oxygenation of N-cyanomethylamines to formamides. Org Biomol Chem 2023; 21:2917-2921. [PMID: 36942930 DOI: 10.1039/d3ob00313b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Selective oxygenation of C(sp3)-H bonds adjacent to nitrogen atoms is a highly attractive strategy for synthesizing various formamide derivatives while preserving the substrate skeletons. Herein, an environmentally benign electrochemically enabled decyanative C(sp3)-H oxygenation of N-cyanomethylamines using H2O as a carbonyl oxygen atom source is described, leading to the synthesis of a large class of formamides in good to excellent yields with a broad substrate scope under metal- and oxidant-free conditions. This electrochemical technology highlights the facile incorporation of N-formyl into some important bioactive molecules.
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Affiliation(s)
- Mu-Jia Luo
- Key Laboratory of Organic Chemistry of Jiangxi Province, Jiangxi Science & Technology Normal University, Nanchang, 330013, China.
| | - Wei Zhou
- Key Laboratory of Organic Chemistry of Jiangxi Province, Jiangxi Science & Technology Normal University, Nanchang, 330013, China.
| | - Ruchun Yang
- Key Laboratory of Organic Chemistry of Jiangxi Province, Jiangxi Science & Technology Normal University, Nanchang, 330013, China.
| | - Haixin Ding
- Key Laboratory of Organic Chemistry of Jiangxi Province, Jiangxi Science & Technology Normal University, Nanchang, 330013, China.
| | - Xian-Rong Song
- Key Laboratory of Organic Chemistry of Jiangxi Province, Jiangxi Science & Technology Normal University, Nanchang, 330013, China.
| | - Qiang Xiao
- Key Laboratory of Organic Chemistry of Jiangxi Province, Jiangxi Science & Technology Normal University, Nanchang, 330013, China.
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12
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Changmai S, Sultana S, Saikia AK. Review of electrochemical transition‐metal‐catalyzed C−H functionalization reactions. ChemistrySelect 2023. [DOI: 10.1002/slct.202203530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/15/2023]
Affiliation(s)
- Sumi Changmai
- Applied Organic Chemistry Chemical Sciences & Technology Division CSIR-North East Institute of Science and Technology 785006 Jorhat India
- Academy of Scientific and Innovative Research (AcSIR) 201002 Ghaziabad India
| | | | - Anil K. Saikia
- Indian Institute of Technology-Guwahati Department of Chemistry Guwahati 781039 Assam India
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13
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Liu HL, He Z, Wang NN, Xu H, Fang P, Mei TS. C(sp 3)-H Alkenylation of Tetrahydroisoquinolines via Merging Electrochemistry and Organocatalysis. Org Lett 2023; 25:608-613. [PMID: 36695740 DOI: 10.1021/acs.orglett.2c04136] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
C(sp3)-H alkenylation of tetrahydroisoquinoline by merging Shono oxidation and the Morita-Baylis-Hillman reaction is developed, employing 4-dimethylaminopyridine as an organocatalyst and TEMPO/NaBr as an electrocatalyst. The reaction proceeds via the interception of an iminium cation intermediate, which is generated in situ from anodic oxidation, leading to aza-Morita-Baylis-Hillman reaction products. Additionally, the use of TEMPO and NaBr as mediators is crucial to avoid the decomposition of products by lowering the oxidation potential of the reaction.
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Affiliation(s)
- Hui-Lin Liu
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P.R. China
| | - Zeng He
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P.R. China
| | - Na-Na Wang
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P.R. China.,Key Laboratory of Pesticides & Chemical Biology Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, P.R. China
| | - Hao Xu
- Key Laboratory of Pesticides & Chemical Biology Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, P.R. China
| | - Ping Fang
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P.R. China
| | - Tian-Sheng Mei
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P.R. China
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14
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Dorchies F, Serva A, Crevel D, De Freitas J, Kostopoulos N, Robert M, Sel O, Salanne M, Grimaud A. Controlling the Hydrophilicity of the Electrochemical Interface to Modulate the Oxygen-Atom Transfer in Electrocatalytic Epoxidation Reactions. J Am Chem Soc 2022; 144:22734-22746. [PMID: 36468903 DOI: 10.1021/jacs.2c10764] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
The electrocatalytic epoxidation of alkenes at heterogeneous catalysts using water as the sole oxygen source is a promising safe route toward the sustainable synthesis of epoxides, which are essential building blocks in organic chemistry. However, the physicochemical parameters governing the oxygen-atom transfer to the alkene and the impact of the electrolyte structure on the epoxidation reaction are yet to be understood. Here, we study the electrocatalytic epoxidation of cyclooctene at the surface of gold in hybrid organic/aqueous mixtures using acetonitrile (ACN) solvent. Gold was selected, as in ACN/water electrolytes gold oxide is formed by reactivity with water at potentials less anodic than the oxygen evolution reaction (OER). This unique property allows us to demonstrate that a sacrificial mechanism is responsible for cyclooctene epoxidation at metallic gold surfaces, proceeding through cyclooctene activation, while epoxidation at gold oxide shares similar reaction intermediates with the OER and proceeds via the activation of water. More importantly, we show that the hydrophilicity of the electrode/electrolyte interface can be tuned by changing the nature of the supporting salt cation, hence affecting the reaction selectivity. At low overpotential, hydrophilic interfaces formed using strong Lewis acid cations are found to favor gold passivation. Instead, hydrophobic interfaces created by the use of large organic cations favor the oxidation of cyclooctene and the formation of epoxide. Our study directly demonstrates how tuning the hydrophilicity of electrochemical interfaces can improve both the yield and selectivity of anodic reactions at the surface of heterogeneous catalysts.
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Affiliation(s)
- Florian Dorchies
- Chimie du Solide et de l'Energie, UMR 8260, Collège de France, 75231Paris Cedex 05, France.,Réseau sur le stockage Electrochimique de l'Energie (RS2E), CNRS FR3459, 80039Amiens Cedex, France
| | - Alessandra Serva
- Réseau sur le stockage Electrochimique de l'Energie (RS2E), CNRS FR3459, 80039Amiens Cedex, France.,Sorbonne Université, CNRS, Physicochimie des Électrolytes et Nanosystèmes Interfaciaux, PHENIX, F-75005Paris, France
| | - Dorian Crevel
- Réseau sur le stockage Electrochimique de l'Energie (RS2E), CNRS FR3459, 80039Amiens Cedex, France.,Université Paris-Saclay, Univ Evry, CNRS, LAMBE, 91025Evry-Courcouronnes, France
| | - Jérémy De Freitas
- Laboratoire d'Electrochimie Moléculaire, Université de Paris, CNRS, F-75006Paris, France
| | - Nikolaos Kostopoulos
- Laboratoire d'Electrochimie Moléculaire, Université de Paris, CNRS, F-75006Paris, France
| | - Marc Robert
- Laboratoire d'Electrochimie Moléculaire, Université de Paris, CNRS, F-75006Paris, France.,Institut Universitaire de France (IUF), 75231Paris, France
| | - Ozlem Sel
- Chimie du Solide et de l'Energie, UMR 8260, Collège de France, 75231Paris Cedex 05, France.,Réseau sur le stockage Electrochimique de l'Energie (RS2E), CNRS FR3459, 80039Amiens Cedex, France
| | - Mathieu Salanne
- Réseau sur le stockage Electrochimique de l'Energie (RS2E), CNRS FR3459, 80039Amiens Cedex, France.,Sorbonne Université, CNRS, Physicochimie des Électrolytes et Nanosystèmes Interfaciaux, PHENIX, F-75005Paris, France.,Institut Universitaire de France (IUF), 75231Paris, France
| | - Alexis Grimaud
- Chimie du Solide et de l'Energie, UMR 8260, Collège de France, 75231Paris Cedex 05, France.,Réseau sur le stockage Electrochimique de l'Energie (RS2E), CNRS FR3459, 80039Amiens Cedex, France.,Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon Street, Chestnut Hill, Massachusetts02467, United States
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15
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Lopat’eva ER, Krylov IB, Lapshin DA, Terent’ev AO. Redox-active molecules as organocatalysts for selective oxidative transformations - an unperceived organocatalysis field. Beilstein J Org Chem 2022; 18:1672-1695. [PMID: 36570566 PMCID: PMC9749543 DOI: 10.3762/bjoc.18.179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 11/23/2022] [Indexed: 12/13/2022] Open
Abstract
Organocatalysis is widely recognized as a key synthetic methodology in organic chemistry. It allows chemists to avoid the use of precious and (or) toxic metals by taking advantage of the catalytic activity of small and synthetically available molecules. Today, the term organocatalysis is mainly associated with redox-neutral asymmetric catalysis of C-C bond-forming processes, such as aldol reactions, Michael reactions, cycloaddition reactions, etc. Organophotoredox catalysis has emerged recently as another important catalysis type which has gained much attention and has been quite well-reviewed. At the same time, there are a significant number of other processes, especially oxidative, catalyzed by redox-active organic molecules in the ground state (without light excitation). Unfortunately, many of such processes are not associated in the literature with the organocatalysis field and thus many achievements are not fully consolidated and systematized. The present article is aimed at overviewing the current state-of-art and perspectives of oxidative organocatalysis by redox-active molecules with the emphasis on challenging chemo-, regio- and stereoselective CH-functionalization processes. The catalytic systems based on N-oxyl radicals, amines, thiols, oxaziridines, ketone/peroxide, quinones, and iodine(I/III) compounds are the most developed catalyst types which are covered here.
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Affiliation(s)
- Elena R Lopat’eva
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow, 119991, Russia
| | - Igor B Krylov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow, 119991, Russia
| | - Dmitry A Lapshin
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow, 119991, Russia
| | - Alexander O Terent’ev
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow, 119991, Russia
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16
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Yao H, Sherer EC, Lu M, Small J, Martin GE, Lam YH, Chen Q, Helmy R, Liu Y, Chen H. One-Step Regio- and Stereoselective Electrochemical Synthesis of Orexin Receptor Antagonist Oxidative Metabolites. J Org Chem 2022; 87:15011-15021. [PMID: 36322780 PMCID: PMC10512451 DOI: 10.1021/acs.joc.2c01311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Synthesis of drug metabolites, which often have complex structures, is an integral step in the evaluation of drug candidate metabolism, pharmacokinetic (PK) properties, and safety profiles. Frequently, such synthetic endeavors entail arduous, multiple-step de novo synthetic routes. Herein, we present the one-step Shono-type electrochemical synthesis of milligrams of chiral α-hydroxyl amide metabolites of two orexin receptor antagonists, MK-8133 and MK-6096, as revealed by a small-scale (pico- to nano-mole level) reaction screening using a lab-built online electrochemistry (EC)/mass spectrometry (MS) (EC/MS) platform. The electrochemical oxidation of MK-8133 and MK-6096 was conducted in aqueous media and found to produce the corresponding α-piperidinols with exclusive regio- and stereoselectivity, as confirmed by high-resolution nuclear magnetic resonance (NMR) characterization of products. Based on density functional theory (DFT) calculations, the exceptional regio- and stereoselectivity for this electrochemical oxidation are governed by more favorable energetics of the transition state, leading to the preferred secondary carbon radical α to the amide group and subsequent steric hindrance associated with the U-shaped conformation of the cation derived from the secondary α-carbon radical, respectively.
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Affiliation(s)
- Huifang Yao
- Department of Pharmacokinetics, Pharmacodynamics and Drug Metabolism, MRL, Merck & Co., Inc., PO Box 2000, Rahway, NJ 07065, USA
| | - Edward C. Sherer
- Analytical Research and Development, MRL, Merck & Co., Inc., PO Box 2000, Rahway, NJ 07065, USA
| | - Mei Lu
- Department of Chemistry & Biochemistry, Ohio University, Athens, OH 45701, USA
| | - James Small
- Analytical Research and Development, MRL, Merck & Co., Inc., PO Box 2000, Rahway, NJ 07065, USA
| | - Gary E. Martin
- Analytical Research and Development, MRL, Merck & Co., Inc., PO Box 2000, Rahway, NJ 07065, USA
| | - Yu-hong Lam
- Computational and Structural Chemistry, MRL, Merck & Co., Inc., PO Box 2000, Rahway, NJ 07065, USA
| | - Qinghao Chen
- Process Research and Development, MRL, Merck & Co., Inc., PO Box 2000, Rahway, NJ 07065, USA
| | - Roy Helmy
- Department of Pharmacokinetics, Pharmacodynamics and Drug Metabolism, MRL, Merck & Co., Inc., PO Box 2000, Rahway, NJ 07065, USA
| | - Yong Liu
- Analytical Research and Development, MRL, Merck & Co., Inc., PO Box 2000, Rahway, NJ 07065, USA
| | - Hao Chen
- Department of Chemistry & Biochemistry, Ohio University, Athens, OH 45701, USA
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, NJ 07102, USA
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17
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Zhang H, Liang S, Wei D, Xu K, Zeng C. Electrocatalytic Generation of Acyl Radicals and Their Applications. European J Org Chem 2022. [DOI: 10.1002/ejoc.202200794] [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)
- Haonan Zhang
- Faculty of Environmental and Life Beijing University of Technology 100 Pingleyuan Rd. 100124 Beijing China
| | - Sen Liang
- Beijing Key Laboratory of Flavor Chemistry Beijing Technology and Business University 100048 Beijing China
| | - Dengchao Wei
- Faculty of Environmental and Life Beijing University of Technology 100 Pingleyuan Rd. 100124 Beijing China
| | - Kun Xu
- Faculty of Environmental and Life Beijing University of Technology 100 Pingleyuan Rd. 100124 Beijing China
| | - Chengchu Zeng
- Faculty of Environmental and Life Beijing University of Technology 100 Pingleyuan Rd. 100124 Beijing China
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18
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Goes SL, Nutting JE, Hill NJ, Stahl SS, Rafiee M. Exploring Electrosynthesis: Bulk Electrolysis and Cyclic Voltammetry Analysis of the Shono Oxidation. JOURNAL OF CHEMICAL EDUCATION 2022; 99:3242-3248. [PMID: 36277842 PMCID: PMC9580565 DOI: 10.1021/acs.jchemed.2c00221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
As electrochemistry continues to gain broader acceptance and use within the organic chemistry community, it is important that advanced undergraduate students are exposed to fundamental and practical knowledge of electrochemical applications for chemical synthesis. Herein, we describe the development of an undergraduate laboratory experience that introduces synthetic and analytical electrochemistry concepts to an advanced organic chemistry class. Experiments focus on the electrooxidative α-functionalization of carbamates, more generally known as the Shono oxidation, and include cyclic voltammetry analysis of two cyclic carbamates and a constant current bulk electrolysis reaction. The exercise offers students an authentic experience in organic electrochemistry, lays a practical and theoretical foundation for future engagement with concepts in electrochemistry and redox chemistry, and strengthens fundamental organic chemistry skills.
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Affiliation(s)
- Shannon L. Goes
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Jordan E. Nutting
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Nicholas J. Hill
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Mohammad Rafiee
- Department of Chemistry, University of Missouri–Kansas City, 5009 Rockhill Rd., Kansas City, MO 1064110, United States
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19
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Hoque MA, Twilton J, Zhu J, Graaf MD, Harper KC, Tuca E, DiLabio GA, Stahl SS. Electrochemical PINOylation of Methylarenes: Improving the Scope and Utility of Benzylic Oxidation through Mediated Electrolysis. J Am Chem Soc 2022; 144:15295-15302. [PMID: 35972068 PMCID: PMC9420808 DOI: 10.1021/jacs.2c05974] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A mediated electrosynthetic method has been developed for selective benzylic oxidation of methylarenes. Phthalimide-N-oxyl (PINO) radical generated by proton-coupled electrochemical oxidation of N-hydroxypthalimide serves as a hydrogen atom-transfer (HAT) mediator and as a radical trap for the benzylic radicals generated in situ. This mediated electrolysis method operates at much lower anode potentials relative to direct electrolysis methods for benzylic oxidation initiated by single-electron transfer (SET). A direct comparison of SET and mediated-HAT electrolysis methods with a common set of substrates shows that the HAT reaction exhibits a significantly improved substrate scope and functional group compatibility. The PINOylated products are readily converted into the corresponding benzylic alcohol or benzaldehyde derivative under photochemical conditions, and the synthetic utility of this method is highlighted by the late-stage functionalization of the non-steroidal anti-inflammatory drug celecoxib.
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Affiliation(s)
- Md Asmaul Hoque
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Jack Twilton
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Jieru Zhu
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Matthew D. Graaf
- Abbvie Process Research and Development, 1401 North Sheridan Road, North Chicago, Illinois 60064, United States
| | - Kaid C. Harper
- Abbvie Process Research and Development, 1401 North Sheridan Road, North Chicago, Illinois 60064, United States
| | - Emilian Tuca
- Department of Chemistry, The University of British Columbia, 3247 University Way, Kelowna, British Columbia V1V 1V7, Canada
| | - Gino A. DiLabio
- Department of Chemistry, The University of British Columbia, 3247 University Way, Kelowna, British Columbia V1V 1V7, Canada
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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20
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Liu L, Xu Z, Liu T, Xu C, Zhang W, Hua X, Ling F, Zhong W. Electrosynthesis of 2-Substituted Benzoxazoles via Intramolecular Shono-Type Oxidative Coupling of Glycine Derivatives. J Org Chem 2022; 87:11379-11386. [PMID: 35951541 DOI: 10.1021/acs.joc.2c00856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Herein, an atom-economical and eco-friendly electrochemical oxidation/cyclization of glycine derivatives through intramolecular Shono-type oxidative coupling is disclosed, leading to a variety of 2-substituted benzoxazoles in 51-85% yields. This oxidative cyclization proceeded in transition metal- and oxidant-free conditions and generated H2 as only a byproduct. Additionally, gram-scale reactions and a broad substrate scope demonstrated the synthetic usefulness of this protocol.
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Affiliation(s)
- Lei Liu
- College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, People's Republic of China.,College of Pharmacy, Qiqihar Medical University, Qiqihar, Heilongjiang 161006, People's Republic of China
| | - Zhenhui Xu
- College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, People's Republic of China
| | - Tao Liu
- College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, People's Republic of China
| | - Chao Xu
- College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, People's Republic of China
| | - Wangqin Zhang
- College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, People's Republic of China
| | - Xiangqi Hua
- College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, People's Republic of China
| | - Fei Ling
- College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, People's Republic of China
| | - Weihui Zhong
- College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, People's Republic of China
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21
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Miller JL, Lawrence JMIA, Rodriguez Del Rey FO, Floreancig PE. Synthetic applications of hydride abstraction reactions by organic oxidants. Chem Soc Rev 2022; 51:5660-5690. [PMID: 35712818 DOI: 10.1039/d1cs01169c] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Carbon-hydrogen bond functionalizations provide an attractive method for streamlining organic synthesis, and many strategies have been developed for conducting these transformations. Hydride-abstracting reactions have emerged as extremely effective methods for oxidative bond-forming processes due to their mild reaction conditions and high chemoselectivity. This review will predominantly focus on the mechanism, reaction development, natural product synthesis applications, approaches to catalysis, and use in enantioselective processes for hydride abstractions by quinone, oxoammonium ion, and carbocation oxidants. These are the most commonly employed hydride-abstracting agents, but recent efforts illustrate the potential for weaker ketone and triaryl borane oxidants, which will be covered at the end of the review.
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Affiliation(s)
- Jenna L Miller
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA.
| | - Jean-Marc I A Lawrence
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA.
| | | | - Paul E Floreancig
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA.
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22
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Gunasekera D, Mahajan JP, Wanzi Y, Rodrigo S, Liu W, Tan T, Luo L. Controlling One- or Two-Electron Oxidation for Selective Amine Functionalization by Alternating Current Frequency. J Am Chem Soc 2022; 144:9874-9882. [PMID: 35622985 DOI: 10.1021/jacs.2c02605] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Here, we report a unique electrosynthetic method that enables the selective one-electron oxidation of tertiary amines to generate α-amino radical intermediates over two-electron oxidation to iminium cations, providing easy access to arylation products by simply applying an optimal alternating current (AC) frequency. More importantly, we have discovered an electrochemical descriptor from cyclic voltammetry studies to predict the optimal AC frequency for various amine substrates, circumventing the time-consuming trial-and-error methods for optimizing reaction conditions. This new development in AC electrolysis provides an alternative strategy to solving challenging chemoselectivity problems in synthetic organic chemistry.
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Affiliation(s)
- Disni Gunasekera
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Jyoti P Mahajan
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Yanick Wanzi
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Sachini Rodrigo
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Wei Liu
- Laboratory of Theoretical and Computational Nanoscience, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, China
| | - Ting Tan
- Laboratory of Theoretical and Computational Nanoscience, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, China
| | - Long Luo
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
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23
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Lawrence JMIA, Floreancig PE. Kinetics-Based Approach to Developing Electrocatalytic Variants of Slow Oxidations: Application to Hydride Abstraction-Initiated Cyclization Reactions. Chemistry 2022; 28:e202200335. [PMID: 35254690 DOI: 10.1002/chem.202200335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Indexed: 01/28/2023]
Abstract
Electrochemical oxidant regeneration is challenging in reactions that have a slow redox step because the steady-state concentration of the reduced oxidant is low, causing difficulties in maintaining sufficient current or preventing potential spikes. This work shows that applying an understanding of the relationship between intermediate cation stability, oxidant strength, overpotential, and concentration on reaction kinetics delivers a method for electrochemical oxoammonium ion regeneration in hydride abstraction-initiated cyclization reactions, resulting in the development of an electrocatalytic variant of a process that has a high oxidation transition state free energy. This approach should be applicable to expanding the scope of electrocatalysis to include additional slow redox processes.
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Affiliation(s)
| | - Paul E Floreancig
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA
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24
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Feng T, Wang S, Qiu Y. Electrochemical C–H Functionalization of Cyclic Amines. Synlett 2022. [DOI: 10.1055/a-1828-1217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Functionalized cyclic amines are essential structural motifs in synthetic chemistry and pharmacy chemistry, and Shono-type oxidation is a well-developed electrochemical approach for the synthesis of α-functionalized amines. In sharp contrast, electrochemically driven direct β-C(sp3)–H functionalization of amines has been far proven elusive. Herein, we outline the recent advances in this field and highlight our group’s effort to achieve electrochemical β-C(sp3)–H functionalization assisted by ferrocene as molecular electrocatalyst under mild conditions.
1 Introduction
2 Case studies of α-functionalization (Shono-type oxidation)
3 Electrochemical β-C(sp3)–H acylation
4 Conclusion
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Affiliation(s)
- Tian Feng
- College of Chemistry, Nankai University, Tianjin, China
| | - Siyi Wang
- College of Chemistry, Nankai University, Tianjin, China
| | - Youai Qiu
- College of Chemistry, Nankai University, Tianjin, China
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25
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Lohmann N, Milovanović V, Piekarski DG, García Mancheño O. Metal-free oxoammonium salt-mediated C(sp 3)-H oxidative Ugi-azide multicomponent reaction. Org Biomol Chem 2022; 20:2896-2908. [PMID: 35319061 DOI: 10.1039/d2ob00101b] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In this work, an efficient oxidative C(sp3)-H Ugi-azide multicomponent reaction of cyclic benzylic amines to the corresponding α-tetrazolo compounds using a TEMPO salt as mild hydride abstractor-type oxidant is reported. This simple one-pot approach allows the direct functionalization of N-heterocycles such as tetrahydroisoquinolines with a variety of isocyanides and NaN3 as a practical azide source. The reaction proceeds at room temperature and without the need of acid additives, allowing for the use of sensitive substrates, while minimizing isocyanide polymerization to provide the desired heterocycle-tetrazole products in synthetically useful yields (up to 99%).
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Affiliation(s)
- Niklas Lohmann
- University of Münster, Organic Chemistry Institute, Corrensstraße 40, 48149 Münster, Germany.
| | - Vesna Milovanović
- University of Münster, Organic Chemistry Institute, Corrensstraße 40, 48149 Münster, Germany. .,University of Kragujevac, Faculty of Agronomy, Department of Chemistry and Chemical Engineering, Cara Dušana 34, 32000 Čačak, Serbia
| | - Dariusz G Piekarski
- Polish Academy of Sciences, Institute of Physical Chemistry, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Olga García Mancheño
- University of Münster, Organic Chemistry Institute, Corrensstraße 40, 48149 Münster, Germany.
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26
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Hatch CE, Martin MI, Gilmartin PH, Xiong L, Beam DJ, Yap GPA, Von Bargen MJ, Rosenthal J, Chain WJ. Electrochemically Mediated Oxidation of Sensitive Propargylic Benzylic Alcohols. Org Lett 2022; 24:1423-1428. [PMID: 35148118 DOI: 10.1021/acs.orglett.1c03860] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The electrochemical oxidation of sensitive propargylic benzylic alcohols having varying substituents is reported. We describe the preparation and characterization of N-hydroxytetrafluorophthalimide (TFNHPI) and pseudo-high-throughput development of a green electrochemical oxidation protocol for sensitive propargylic benzylic alcohols that employs TFNHPI as a stable electrochemical mediator. The electrochemical oxidation of propargylic benzylic alcohols was leveraged to develop short synthetic pathways for preparing gram quantities of resveratrol natural products such as pauciflorols.
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Affiliation(s)
- Chad E Hatch
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Maxwell I Martin
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Philip H Gilmartin
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Lu Xiong
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Danielle J Beam
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Glenn P A Yap
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Matthew J Von Bargen
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Joel Rosenthal
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - William J Chain
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, United States
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27
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Wang Q, Yao X, Xu XJ, Zhang S, Ren L. Electrochemical [4 + 1] Tandem sp 3(C-H) Double Amination for the Direct Synthesis of 3-Acyl-Functionalized Imidazo[1,5- a]pyridines. ACS OMEGA 2022; 7:4305-4310. [PMID: 35155923 PMCID: PMC8829863 DOI: 10.1021/acsomega.1c06029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
3-Acyl imidazo[1,5-a]pyridines, featured pharmaceutical moieties that were prepared by a three-step reaction conventionally, could be obtained in one step by an electrochemical tandem sp3 (C-H) double amination of acetophenones with pyridine ethylamines using ammonium iodide as a redox mediator.
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Affiliation(s)
- Qiang Wang
- Research
Center For Biomedical And Health Science, Anhui Science and Technology University, Fengyang 233100, P. R. China
| | - Xia Yao
- Research
Center For Biomedical And Health Science, Anhui Science and Technology University, Fengyang 233100, P. R. China
| | - Xian-jing Xu
- Research
Center For Biomedical And Health Science, Anhui Science and Technology University, Fengyang 233100, P. R. China
| | - Shuai Zhang
- Nanjing
Harris Bio-Pharmaceutical Technology Co., Ltd., Nanjing, Jiangsu 210000, China
| | - Lei Ren
- Department
of Material and Chemical Engineering, Bengbu
University, Bengbu, Anhui 233030, P. R. China
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28
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Feng T, Wang S, Liu Y, Liu S, Qiu Y. Electrochemical Desaturative β‐Acylation of Cyclic
N
‐Aryl Amines. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202115178] [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)
- Tian Feng
- State Key Laboratory and Institute of Elemento-Organic Chemistry Frontiers Science Center for New Organic Matter College of Chemistry Nankai University 94 Weijin Road Tianjin 300071 China
| | - Siyi Wang
- State Key Laboratory and Institute of Elemento-Organic Chemistry Frontiers Science Center for New Organic Matter College of Chemistry Nankai University 94 Weijin Road Tianjin 300071 China
| | - Yin Liu
- State Key Laboratory and Institute of Elemento-Organic Chemistry Frontiers Science Center for New Organic Matter College of Chemistry Nankai University 94 Weijin Road Tianjin 300071 China
| | - Shouzhuo Liu
- State Key Laboratory and Institute of Elemento-Organic Chemistry Frontiers Science Center for New Organic Matter College of Chemistry Nankai University 94 Weijin Road Tianjin 300071 China
| | - Youai Qiu
- State Key Laboratory and Institute of Elemento-Organic Chemistry Frontiers Science Center for New Organic Matter College of Chemistry Nankai University 94 Weijin Road Tianjin 300071 China
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29
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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: 123] [Impact Index Per Article: 61.5] [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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30
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Novaes LFT, Ho JSK, Mao K, Liu K, Tanwar M, Neurock M, Villemure E, Terrett JA, Lin S. Exploring Electrochemical C(sp 3)-H Oxidation for the Late-Stage Methylation of Complex Molecules. J Am Chem Soc 2022; 144:1187-1197. [PMID: 35015533 DOI: 10.1021/jacs.1c09412] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The "magic methyl" effect, a dramatic boost in the potency of biologically active compounds from the incorporation of a single methyl group, provides a simple yet powerful strategy employed by medicinal chemists in the drug discovery process. Despite significant advances, methodologies that enable the selective C(sp3)-H methylation of structurally complex medicinal agents remain very limited. In this work, we disclose a modular, efficient, and selective strategy for the α-methylation of protected amines (i.e., amides, carbamates, and sulfonamides) by means of electrochemical oxidation. Mechanistic analysis guided our development of an improved electrochemical protocol on the basis of the classic Shono oxidation reaction, which features broad reaction scope, high functional group compatibility, and operational simplicity. Importantly, this reaction system is amenable to the late-stage functionalization of complex targets containing basic nitrogen groups that are prevalent in medicinally active agents. When combined with organozinc-mediated C-C bond formation, our protocol enabled the direct methylation of a myriad of amine derivatives including those that have previously been explored for the "magic methyl" effect. This synthesis strategy thus circumvents multistep de novo synthesis that is currently necessary to access such compounds and has the potential to accelerate drug discovery efforts.
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Affiliation(s)
- Luiz F T Novaes
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Justin S K Ho
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Kaining Mao
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Kaida Liu
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Mayank Tanwar
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Matthew Neurock
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Elisia Villemure
- Department of Discovery Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Jack A Terrett
- Department of Discovery Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Song Lin
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
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31
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Iwabuchi Y, Nagasawa S. The Utility of Oxoammonium Species in Organic Synthesis: Beyond Alcohol Oxidation. HETEROCYCLES 2022. [DOI: 10.3987/rev-21-sr(r)2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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32
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Lian P, Li R, Wang L, Wan X, Xiang Z, Wan X. Photoredox aerobic oxidation of unreactive amine derivatives through LMCT excitation of copper dichloride. Org Chem Front 2022. [DOI: 10.1039/d2qo01032a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Taking advantage of the chlorine radical as a HAT catalyst, a versatile oxidation system for unreactive amines has been well established.
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Affiliation(s)
- Pengcheng Lian
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Ruyi Li
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Lili Wang
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Xiao Wan
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Zixin Xiang
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Xiaobing Wan
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
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33
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Electrochemical Oxidative C H Phosphonylation of thiazole derivatives in ambient conditions. MOLECULAR CATALYSIS 2022. [DOI: 10.1016/j.mcat.2021.112022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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34
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Feng T, Wang S, Liu Y, Liu S, Qiu Y. Electrochemical Desaturative β-Acylation of Cyclic N-Aryl Amines. Angew Chem Int Ed Engl 2021; 61:e202115178. [PMID: 34878215 DOI: 10.1002/anie.202115178] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Indexed: 12/15/2022]
Abstract
Herein, we disclose a straightforward, robust, and simple route to access β-substituted desaturated cyclic amines via an electrochemically driven desaturative β-functionalization of cyclic amines. This transformation is based on multiple single-electron oxidation processes using catalytic amounts of ferrocene. The reaction proceeds in the absence of stoichiometric amounts of electrolyte under mild conditions, affording the desired products with high chemo- and regioselectivity. The reaction was tolerant of a broad range of substrates and also enables late-stage β-C(sp3 )-H acylation of potentially valuable products. Preliminary mechanistic studies using cyclic voltammetry reveal the key role of ferrocene as a redox mediator in the reaction.
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Affiliation(s)
- Tian Feng
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Siyi Wang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Yin Liu
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Shouzhuo Liu
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Youai Qiu
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
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35
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Rafiee M, Mayer MN, Punchihewa BT, Mumau MR. Constant Potential and Constant Current Electrolysis: An Introduction and Comparison of Different Techniques for Organic Electrosynthesis. J Org Chem 2021; 86:15866-15874. [PMID: 34546751 DOI: 10.1021/acs.joc.1c01391] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electrosynthesis involves transferring charge between two electrodes to promote chemical reactions by applying potential. The modes of controlling the current and potential can affect the reaction mechanism, product distribution and yields, and add a control factor for reaction optimization. In this Synopsis, theoretical discussion is applied to specific case studies from the literature to illustrate methods of adjusting and tracking electrical parameters for the optimization and monitoring of electroorganic reactions.
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Affiliation(s)
- Mohammad Rafiee
- Department of Chemistry, University of Missouri-Kansas City, 5009 Rockhill Road, Kansas City, Missouri 64110, United States
| | - Mikayla N Mayer
- Department of Chemistry, University of Missouri-Kansas City, 5009 Rockhill Road, Kansas City, Missouri 64110, United States
| | - Buwanila T Punchihewa
- Department of Chemistry, University of Missouri-Kansas City, 5009 Rockhill Road, Kansas City, Missouri 64110, United States
| | - Matthew R Mumau
- Department of Chemistry, University of Missouri-Kansas City, 5009 Rockhill Road, Kansas City, Missouri 64110, United States
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36
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Deprez NR, Clausen DJ, Yan JX, Peng F, Zhang S, Kong J, Bai Y. Selective Electrochemical Oxidation of Functionalized Pyrrolidines. Org Lett 2021; 23:8834-8837. [PMID: 34730984 DOI: 10.1021/acs.orglett.1c03338] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A method for the selective electrochemical aminoxyl-mediated Shono-type oxidation of pyrrolidines to pyrrolidinones is described. These transformations show the high selectivity and functional group compatibility. This chemistry also demonstrates the use of an operationally simple ElectraSyn 2.0 and cost-effective stainless-steel electrode for the electrochemical oxidation of functionalized pyrrolidines.
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Affiliation(s)
- Nicholas R Deprez
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Dane J Clausen
- Discovery Chemistry, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Jia-Xuan Yan
- Analytical Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Feng Peng
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Shaoguang Zhang
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Jongrock Kong
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Yanguang Bai
- WuXi AppTec (Tianjin) Co. Ltd., Tianjin 300457, China
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37
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Nutting JE, Gerken JB, Stamoulis AG, Bruns DL, Stahl SS. "How Should I Think about Voltage? What Is Overpotential?": Establishing an Organic Chemistry Intuition for Electrochemistry. J Org Chem 2021; 86:15875-15885. [PMID: 34609137 DOI: 10.1021/acs.joc.1c01520] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Redox reactions are ubiquitous in organic synthesis and intrinsic to organic electrosynthesis. The language and concepts used to describe reactions in these domains are sufficiently different to create barriers that hinder broader adoption and understanding of electrochemical methods. To bridge these gaps, this Synopsis compares chemical and electrochemical redox reactions, including concepts of free energy, voltage, kinetic barriers, and overpotential. This discussion is intended to increase the accessibility of electrochemistry for organic chemists lacking formal training in this area.
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Affiliation(s)
- Jordan E Nutting
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - James B Gerken
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Alexios G Stamoulis
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - David L Bruns
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Shannon S Stahl
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
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38
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Wang ZH, Gao PS, Wang X, Gao JQ, Xu XT, He Z, Ma C, Mei TS. TEMPO-Enabled Electrochemical Enantioselective Oxidative Coupling of Secondary Acyclic Amines with Ketones. J Am Chem Soc 2021; 143:15599-15605. [PMID: 34533943 DOI: 10.1021/jacs.1c08671] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
An electrochemical asymmetric coupling of secondary acyclic amines with ketones via a Shono-type oxidation has been described, affording the corresponding amino acid derivatives with good to excellent diastereoselectivity and enantioselectivity. The addition of an N-oxyl radical as a redox mediator could selectively oxidize the substrate rather than the product, although their oxidation potential difference is subtle (about 13 mV). This electrochemical transformation proceeds in the absence of stoichiometric additives, including metals, oxidants, and electrolytes, which gives it good functional group compatibility. Mechanistic studies suggest that proton-mediated racemization of the product is prevented by the reduction of protons at the cathode.
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Affiliation(s)
- Zhen-Hua Wang
- Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Science, 345 Lingling Road, Shanghai 200032, People's Republic of China
| | - Pei-Sen Gao
- Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Science, 345 Lingling Road, Shanghai 200032, People's Republic of China
| | - Xiu Wang
- Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Science, 345 Lingling Road, Shanghai 200032, People's Republic of China
| | - Jun-Qing Gao
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, People's Republic of China
| | - Xue-Tao Xu
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, People's Republic of China
| | - Zeng He
- Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Science, 345 Lingling Road, Shanghai 200032, People's Republic of China
| | - Cong Ma
- Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Science, 345 Lingling Road, Shanghai 200032, People's Republic of China
| | - Tian-Sheng Mei
- Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Science, 345 Lingling Road, Shanghai 200032, People's Republic of China
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39
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Dutta S, Li B, Rickertsen DRL, Valles DA, Seidel D. C-H Bond Functionalization of Amines: A Graphical Overview of Diverse Methods. SYNOPEN 2021; 5:173-228. [PMID: 34825124 PMCID: PMC8612105 DOI: 10.1055/s-0040-1706051] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
This Graphical Review provides a concise overview of the manifold and mechanistically diverse methods that enable the functionalization of sp3 C-H bonds in amines and their derivatives.
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Affiliation(s)
- Subhradeep Dutta
- Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Bowen Li
- Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Dillon R L Rickertsen
- Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Daniel A Valles
- Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Daniel Seidel
- Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
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40
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Novaes LFT, Liu J, Shen Y, Lu L, Meinhardt JM, Lin S. Electrocatalysis as an enabling technology for organic synthesis. Chem Soc Rev 2021; 50:7941-8002. [PMID: 34060564 PMCID: PMC8294342 DOI: 10.1039/d1cs00223f] [Citation(s) in RCA: 359] [Impact Index Per Article: 119.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Electrochemistry has recently gained increased attention as a versatile strategy for achieving challenging transformations at the forefront of synthetic organic chemistry. Electrochemistry's unique ability to generate highly reactive radical and radical ion intermediates in a controlled fashion under mild conditions has inspired the development of a number of new electrochemical methodologies for the preparation of valuable chemical motifs. Particularly, recent developments in electrosynthesis have featured an increased use of redox-active electrocatalysts to further enhance control over the selective formation and downstream reactivity of these reactive intermediates. Furthermore, electrocatalytic mediators enable synthetic transformations to proceed in a manner that is mechanistically distinct from purely chemical methods, allowing for the subversion of kinetic and thermodynamic obstacles encountered in conventional organic synthesis. This review highlights key innovations within the past decade in the area of synthetic electrocatalysis, with emphasis on the mechanisms and catalyst design principles underpinning these advancements. A host of oxidative and reductive electrocatalytic methodologies are discussed and are grouped according to the classification of the synthetic transformation and the nature of the electrocatalyst.
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Affiliation(s)
- Luiz F T Novaes
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.
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41
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Najmi AA, Bhat MF, Bischoff R, Poelarends GJ, Permentier HP. TEMPO‐Mediated Electrochemical N‐demethylation of Opiate Alkaloids. ChemElectroChem 2021. [DOI: 10.1002/celc.202100784] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Ali Alipour Najmi
- Department of Analytical Biochemistry Groningen Research Institute of Pharmacy University of Groningen A. Deusinglaan 1 9713 AV Groningen The Netherlands
| | - M. Faizan Bhat
- Department of Chemical and Pharmaceutical Biology Groningen Research Institute of Pharmacy University of Groningen A. Deusinglaan 1 9713 AV Groningen The Netherlands
| | - Rainer Bischoff
- Department of Analytical Biochemistry Groningen Research Institute of Pharmacy University of Groningen A. Deusinglaan 1 9713 AV Groningen The Netherlands
| | - Gerrit J. Poelarends
- Department of Chemical and Pharmaceutical Biology Groningen Research Institute of Pharmacy University of Groningen A. Deusinglaan 1 9713 AV Groningen The Netherlands
| | - Hjalmar P. Permentier
- Department of Analytical Biochemistry Groningen Research Institute of Pharmacy University of Groningen A. Deusinglaan 1 9713 AV Groningen The Netherlands
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42
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Grigor’eva LN, Tikhonov AY, Lomanovich KA, Mazhukin DG. Stable Bicyclic Functionalized Nitroxides: The Synthesis of Derivatives of Aza-nortropinone-5-Methyl-3-oxo-6,8-diazabicyclo[3.2.1]-6-octene 8-oxyls. Molecules 2021; 26:molecules26103050. [PMID: 34065372 PMCID: PMC8161028 DOI: 10.3390/molecules26103050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 11/24/2022] Open
Abstract
In recent decades, bicyclic nitroxyl radicals have caught chemists’ attention as selective catalysts for the oxidation of alcohols and amines and as additives and mediators in directed C-H oxidative transformations. In this regard, the design and development of synthetic approaches to new functional bicyclic nitroxides is a relevant and important issue. It has been reported that imidazo[1,2-b]isoxazoles formed during the condensation of acetylacetone with 2-hydroxyaminooximes having a secondary hydroxyamino group are recyclized under mild basic catalyzed conditions to 8-hydroxy-5-methyl-3-oxo-6,8-diazabicyclo[3.2.1]-6-octenes. The latter, containing a sterically hindered cyclic N-hydroxy group, upon oxidation with lead dioxide in acetone, virtually quantitatively form stable nitroxyl bicyclic radicals of a new class, which are derivatives of both 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl (TEMPON) and 3-imidazolines.
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Affiliation(s)
| | - Alexsei Ya. Tikhonov
- Correspondence: (A.Y.T.); (D.G.M.); Tel.: +7-383-330-8867 (A.Y.T.); +7-383-330-6852 (D.G.M.)
| | | | - Dmitrii G. Mazhukin
- Correspondence: (A.Y.T.); (D.G.M.); Tel.: +7-383-330-8867 (A.Y.T.); +7-383-330-6852 (D.G.M.)
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43
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Cembellín S, Batanero B. Organic Electrosynthesis Towards Sustainability: Fundamentals and Greener Methodologies. CHEM REC 2021; 21:2453-2471. [PMID: 33955158 DOI: 10.1002/tcr.202100128] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 04/19/2021] [Indexed: 12/20/2022]
Abstract
The adoption of new measures that preserve our environment, on which our survival depends, is a necessity. Electro-organic processes are sustainable per se, by producing the activation of a substrate by electron transfer at normal pressure and room temperature. In the recent years, a highly crescent number of works on organic electrosynthesis are available. Novel strategies at the electrode are being developed enabling the construction of a great variety of complex organic molecules. However, the possibility of being scaled-up is mandatory in terms of sustainability. Thus, some electrochemical methodologies have demonstrated to report the best results in reducing pollution and saving energy. In this personal account, these methods have been compiled, being organized as follows: • Direct discharge electrosynthesis • Paired electrochemical reactions. and • Organic transformations utilizing electrocatalysis (in absence of heavy metals). Selected protocols are herein presented and discussed with representative recent examples. Final perspectives and reflections are also considered.
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Affiliation(s)
- Sara Cembellín
- University of Alcala, Organic and Inorganic Chemistry Department (Organic area), Campus, km 33,6 A2, 28805, Alcalá de Henares, Madrid, Spain
| | - Belén Batanero
- University of Alcala, Organic and Inorganic Chemistry Department (Organic area), Campus, km 33,6 A2, 28805, Alcalá de Henares, Madrid, Spain.,Instituto de Investigación Química, "Andrés M. del Río" (IQAR) University of Alcala
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44
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Zhu C, Ang NWJ, Meyer TH, Qiu Y, Ackermann L. Organic Electrochemistry: Molecular Syntheses with Potential. ACS CENTRAL SCIENCE 2021; 7:415-431. [PMID: 33791425 PMCID: PMC8006177 DOI: 10.1021/acscentsci.0c01532] [Citation(s) in RCA: 228] [Impact Index Per Article: 76.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Indexed: 05/05/2023]
Abstract
Efficient and selective molecular syntheses are paramount to inter alia biomolecular chemistry and material sciences as well as for practitioners in chemical, agrochemical, and pharmaceutical industries. Organic electrosynthesis has undergone a considerable renaissance and has thus in recent years emerged as an increasingly viable platform for the sustainable molecular assembly. In stark contrast to early strategies by innate reactivity, electrochemistry was recently merged with modern concepts of organic synthesis, such as transition-metal-catalyzed transformations for inter alia C-H functionalization and asymmetric catalysis. Herein, we highlight the unique potential of organic electrosynthesis for sustainable synthesis and catalysis, showcasing key aspects of exceptional selectivities, the synergism with photocatalysis, or dual electrocatalysis, and novel mechanisms in metallaelectrocatalysis until February of 2021.
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Affiliation(s)
- Cuiju Zhu
- Institut
für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstraße 2, 37077 Göttingen, Germany
| | - Nate W. J. Ang
- Institut
für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstraße 2, 37077 Göttingen, Germany
| | - Tjark H. Meyer
- Institut
für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstraße 2, 37077 Göttingen, Germany
- Woehler
Research Institute for Sustainable Chemistry (WISCh), Georg-August-Universität Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany
| | - Youai Qiu
- Institut
für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstraße 2, 37077 Göttingen, Germany
| | - Lutz Ackermann
- Institut
für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstraße 2, 37077 Göttingen, Germany
- Woehler
Research Institute for Sustainable Chemistry (WISCh), Georg-August-Universität Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany
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45
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Yamamoto K, Kuriyama M, Onomura O. Shono-Type Oxidation for Functionalization of N-Heterocycles. CHEM REC 2021; 21:2239-2253. [PMID: 33656281 DOI: 10.1002/tcr.202100031] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/24/2021] [Accepted: 02/24/2021] [Indexed: 01/05/2023]
Abstract
The development of facile synthetic methods for stereodefined aliphatic cyclic amines is an important research field in synthetic organic chemistry since such scaffolds constitute a variety of natural products and biologically active compounds. N-Acyl cyclic N,O-acetals which prepared by electrochemical oxidation of the corresponding cyclic amines have proven to be useful and versatile precursors for the synthesis of such skeletons. In this Personal Account, we introduce our efforts toward the development of synthetic strategies for the diastereo- and/or enantioselective synthesis of cyclic amines by using electrochemically prepared cyclic N,O-acetals. In addition, the investigation of the "memory of chirality" in the electrooxidative methoxylation of N-acyl amino acid derivatives, the strategy for the synthesis of chiral azabicyclic compounds by utilizing electrochemical oxidation, and halogen cation-mediated synthesis of nitrogen-containing heterocycles are also described.
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Affiliation(s)
- Kosuke Yamamoto
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan
| | - Masami Kuriyama
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan
| | - Osamu Onomura
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan
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46
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Chen Y, Tian B, Cheng Z, Li X, Huang M, Sun Y, Liu S, Cheng X, Li S, Ding M. Electro-Descriptors for the Performance Prediction of Electro-Organic Synthesis. Angew Chem Int Ed Engl 2021; 60:4199-4207. [PMID: 33180375 DOI: 10.1002/anie.202014072] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Indexed: 12/20/2022]
Abstract
Electrochemical organic synthesis has attracted increasing attentions as a sustainable and versatile synthetic platform. Quantitative assessment of the electro-organic reactions, including reaction thermodynamics, electro-kinetics, and coupled chemical processes, can lead to effective analytical tool to guide their future design. Herein, we demonstrate that electrochemical parameters such as onset potential, Tafel slope, and effective voltage can be utilized as electro-descriptors for the evaluation of reaction conditions and prediction of reactivities (yields). An "electro-descriptor-diagram" is generated, where reactive and non-reactive conditions/substances show distinct boundary. Successful predictions of reaction outcomes have been demonstrated using electro-descriptor diagram, or from machine learning algorithms with experimentally-derived electro-descriptors. This method represents a promising tool for data-acquisition, reaction prediction, mechanistic investigation, and high-throughput screening for general organic electro-synthesis.
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Affiliation(s)
- Yuxuan Chen
- Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Bailin Tian
- Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Zheng Cheng
- Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.,Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Xiaoshan Li
- Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Min Huang
- Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Yuxia Sun
- Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Shuai Liu
- Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Xu Cheng
- Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Shuhua Li
- Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.,Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Mengning Ding
- Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
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47
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Chen J, Yang H, Zhang M, Chen H, Liu J, Yin K, Chen S, Shao A. Electrochemical-induced regioselective C-3 thiocyanation of imidazoheterocycles with hydrogen evolution. Tetrahedron Lett 2021. [DOI: 10.1016/j.tetlet.2020.152755] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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48
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Luo J, Hu B, Wu W, Hu M, Liu TL. Nickel‐Catalyzed Electrochemical C(sp
3
)−C(sp
2
) Cross‐Coupling Reactions of Benzyl Trifluoroborate and Organic Halides**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202014244] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Jian Luo
- Department of Chemistry and Biochemistry Utah State University 0300 Old Main Hill Logan UT 84322 USA
| | - Bo Hu
- Department of Chemistry and Biochemistry Utah State University 0300 Old Main Hill Logan UT 84322 USA
| | - Wenda Wu
- Department of Chemistry and Biochemistry Utah State University 0300 Old Main Hill Logan UT 84322 USA
| | - Maowei Hu
- Department of Chemistry and Biochemistry Utah State University 0300 Old Main Hill Logan UT 84322 USA
| | - T. Leo Liu
- Department of Chemistry and Biochemistry Utah State University 0300 Old Main Hill Logan UT 84322 USA
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49
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Luo J, Hu B, Wu W, Hu M, Liu TL. Nickel‐Catalyzed Electrochemical C(sp
3
)−C(sp
2
) Cross‐Coupling Reactions of Benzyl Trifluoroborate and Organic Halides**. Angew Chem Int Ed Engl 2021; 60:6107-6116. [DOI: 10.1002/anie.202014244] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/22/2020] [Indexed: 02/02/2023]
Affiliation(s)
- Jian Luo
- Department of Chemistry and Biochemistry Utah State University 0300 Old Main Hill Logan UT 84322 USA
| | - Bo Hu
- Department of Chemistry and Biochemistry Utah State University 0300 Old Main Hill Logan UT 84322 USA
| | - Wenda Wu
- Department of Chemistry and Biochemistry Utah State University 0300 Old Main Hill Logan UT 84322 USA
| | - Maowei Hu
- Department of Chemistry and Biochemistry Utah State University 0300 Old Main Hill Logan UT 84322 USA
| | - T. Leo Liu
- Department of Chemistry and Biochemistry Utah State University 0300 Old Main Hill Logan UT 84322 USA
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Molecular S = 2 High-Spin, S = 0 Low-Spin and S = 0 ⇄ 2 Spin-Transition/-Crossover Nickel(II)-Bis(nitroxide) Coordination Compounds. INORGANICS 2021. [DOI: 10.3390/inorganics9020010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Heterospin systems have a great advantage in frontier orbital engineering since they utilize a wide diversity of paramagnetic chromophores and almost infinite combinations and mutual geometries. Strong exchange couplings are expected in 3d–2p heterospin compounds, where the nitroxide (aminoxyl) oxygen atom has a direct coordination bond with a nickel(II) ion. Complex formation of nickel(II) salts and tert-butyl 2-pyridyl nitroxides afforded a discrete 2p–3d–2p triad. Ferromagnetic coupling is favored when the magnetic orbitals, nickel(II) dσ and radical π*, are arranged in a strictly orthogonal fashion, namely, a planar coordination structure is characterized. In contrast, a severe twist around the coordination bond gives an orbital overlap, resulting in antiferromagnetic coupling. Non-chelatable nitroxide ligands are available for highly twisted and practically diamagnetic complexes. Here, the Ni–O–N–Csp2 torsion (dihedral) angle is supposed to be a useful metric to describe the nickel ion dislocated out of the radical π* nodal plane. Spin-transition complexes exhibited a planar coordination structure in a high-temperature phase and a nonplanar structure in a low-temperature phase. The gradual spin transition is described as a spin equilibrium obeying the van’t Hoff law. Density functional theory calculation indicates that the energy level crossing of the high- and low-spin states. The optimized structures of diamagnetic and high-spin states well agreed with the experimental large and small torsions, respectively. The novel mechanism of the present spin transition lies in the ferro-/antiferromagnetic coupling switch. The entropy-driven mechanism is plausible after combining the results of the related copper(II)-nitroxide compounds. Attention must be paid to the coupling parameter J as a variable of temperature in the magnetic analysis of such spin-transition materials. For future work, the exchange coupling may be tuned by chemical modification and external stimulus, because it has been clarified that the parameter is sensitive to the coordination structure and actually varies from 2J/kB = +400 K to −1400 K.
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