1
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Moianos D, Makri M, Prifti GM, Chiotellis A, Pappas A, Woodson ME, Tajwar R, Tavis JE, Zoidis G. N-Hydroxypiridinedione: A Privileged Heterocycle for Targeting the HBV RNase H. Molecules 2024; 29:2942. [PMID: 38931006 PMCID: PMC11206691 DOI: 10.3390/molecules29122942] [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: 05/29/2024] [Revised: 06/12/2024] [Accepted: 06/16/2024] [Indexed: 06/28/2024] Open
Abstract
Hepatitis B virus (HBV) remains a global health threat. Ribonuclease H (RNase H), part of the virus polymerase protein, cleaves the pgRNA template during viral genome replication. Inhibition of RNase H activity prevents (+) DNA strand synthesis and results in the accumulation of non-functional genomes, terminating the viral replication cycle. RNase H, though promising, remains an under-explored drug target against HBV. We previously reported the identification of a series of N-hydroxypyridinedione (HPD) imines that effectively inhibit the HBV RNase H. In our effort to further explore the HPD scaffold, we designed, synthesized, and evaluated 18 novel HPD oximes, as well as 4 structurally related minoxidil derivatives and 2 barbituric acid counterparts. The new analogs were docked on the RNase H active site and all proved able to coordinate the two Mg2+ ions in the catalytic site. All of the new HPDs effectively inhibited the viral replication in cell assays exhibiting EC50 values in the low μM range (1.1-7.7 μM) with low cytotoxicity, resulting in selectivity indexes (SI) of up to 92, one of the highest reported to date among HBV RNase H inhibitors. Our findings expand the structure-activity relationships on the HPD scaffold, facilitating the development of even more potent anti-HBV agents.
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Affiliation(s)
- Dimitrios Moianos
- Division of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece; (D.M.); (M.M.); (G.-M.P.)
| | - Maria Makri
- Division of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece; (D.M.); (M.M.); (G.-M.P.)
| | - Georgia-Myrto Prifti
- Division of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece; (D.M.); (M.M.); (G.-M.P.)
| | - Aristeidis Chiotellis
- Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, National Center for Scientific Research “Demokritos”, 15310 Athens, Greece; (A.C.); (A.P.)
| | - Alexandros Pappas
- Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, National Center for Scientific Research “Demokritos”, 15310 Athens, Greece; (A.C.); (A.P.)
| | - Molly E. Woodson
- Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA; (M.E.W.); (R.T.); (J.E.T.)
| | - Razia Tajwar
- Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA; (M.E.W.); (R.T.); (J.E.T.)
| | - John E. Tavis
- Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA; (M.E.W.); (R.T.); (J.E.T.)
| | - Grigoris Zoidis
- Division of Pharmaceutical Chemistry, Department of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece; (D.M.); (M.M.); (G.-M.P.)
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2
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Liu J, Du J, Zhang LB, Li M, Guo W. Electrochemical Benzylic C-H Amination via N-Aminopyridinium. J Org Chem 2024; 89:6465-6473. [PMID: 38644574 DOI: 10.1021/acs.joc.4c00502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
An electrochemical protocol for benzylic C(sp3)-H aminopyridylation via direct C-H/N-H cross-coupling of alkylarenes with N-aminopyridinium triflate has been developed. This method features excellent site-selectivity, broad substrate scope, redox reagent-free and facile scalability. The generated benzylaminopyridiniums can be readily converted to benzylamines via electroreductive N-N bond cleavage.
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Affiliation(s)
- Jingwei Liu
- College of Chemistry and Molecular Engineering, Qingdao University of Science & Technology, Qingdao 266042, China
| | - Jinyao Du
- College of Chemistry and Molecular Engineering, Qingdao University of Science & Technology, Qingdao 266042, China
| | - Lin-Bao Zhang
- College of Chemistry and Molecular Engineering, Qingdao University of Science & Technology, Qingdao 266042, China
| | - Ming Li
- College of Chemistry and Molecular Engineering, Qingdao University of Science & Technology, Qingdao 266042, China
| | - Weisi Guo
- College of Chemistry and Molecular Engineering, Qingdao University of Science & Technology, Qingdao 266042, China
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3
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Zhang Z, Lv Y, Ji L, Chen P, Han S, Zhu Y, Li L, Jia Z, Loh TP. Triaryl Carbenium Ion Pair Mediated Electrocatalytic Benzylic C-H Oxygenation in Air. Angew Chem Int Ed Engl 2024:e202406588. [PMID: 38664822 DOI: 10.1002/anie.202406588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Indexed: 06/05/2024]
Abstract
The selective oxidation of benzylic C-H bonds is a pivotal transformation in organic synthesis. Undoubtedly, achieving efficient and highly selective aerobic oxidation of methylarenes to benzaldehydes has been highly challenging due to the propensity of benzaldehyde to undergo overoxidation under typical aerobic conditions. Herein, we propose an innovative approach to address this issue by leveraging electrocatalytic processes, facilitated by ion-pair mediators [Ph3C]+[B(C6F5)4]-. By harnessing the power of electrochemistry, we successfully demonstrated the effectiveness of our strategy, which enables the selective oxidation of benzylic C-H bonds in benzylic molecules and toluene derivatives. Notably, our approach exhibited high efficiency, excellent selectivity, and compatibility with various functional groups, underscoring the broad applicability of our methodology.
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Affiliation(s)
- Zhenguo Zhang
- Henan University of Technology, 100 Lianhua Street, Zhongyuan District, Zhengzhou, 450001, China
- Division of Chemistry and Biological Chemistry, School of Chemistry Chemical Engineering & Biotechnology, Nanyang Technological University, 21 Nanyang Link, Nanyang, 637371, Singapore
| | - Yongheng Lv
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Liang Ji
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Peng Chen
- Henan University of Technology, 100 Lianhua Street, Zhongyuan District, Zhengzhou, 450001, China
| | - Shuyan Han
- Henan University of Technology, 100 Lianhua Street, Zhongyuan District, Zhengzhou, 450001, China
| | - Yufei Zhu
- Henan University of Technology, 100 Lianhua Street, Zhongyuan District, Zhengzhou, 450001, China
| | - Lanyang Li
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Zhenhua Jia
- Henan University of Technology, 100 Lianhua Street, Zhongyuan District, Zhengzhou, 450001, China
- Division of Chemistry and Biological Chemistry, School of Chemistry Chemical Engineering & Biotechnology, Nanyang Technological University, 21 Nanyang Link, Nanyang, 637371, Singapore
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Teck-Peng Loh
- Henan University of Technology, 100 Lianhua Street, Zhongyuan District, Zhengzhou, 450001, China
- Division of Chemistry and Biological Chemistry, School of Chemistry Chemical Engineering & Biotechnology, Nanyang Technological University, 21 Nanyang Link, Nanyang, 637371, Singapore
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
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4
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Alcázar J, Anderson EA, Davies HML, Febrian R, Kelly CB, Noël T, Voight EA, Zarate C, Zysman-Colman E. Better Together: Catalyzing Innovation in Organic Synthesis via Academic-Industrial Consortia. Org Lett 2024; 26:2677-2681. [PMID: 38284620 DOI: 10.1021/acs.orglett.4c00192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2024]
Affiliation(s)
- Jesús Alcázar
- Global Discovery Chemistry, Johnson & Johnson Innovative Medicine, Janssen-Cilag, S. A., Jarama 75 A, 45007 Toledo, Spain
| | - Edward A Anderson
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Huw M L Davies
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Rio Febrian
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Christopher B Kelly
- Discovery Process Research, Johnson & Johnson Innovative Medicine, 1400 McKean Road, Spring House, Pennsylvania 19477, United States
| | - Timothy Noël
- Flow Chemistry Group, van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Eric A Voight
- Discovery Research, AbbVie, Inc., 1 N Waukegan Rd, North Chicago, Illinois 60064, United States
| | - Cayetana Zarate
- Chemical Process R&D, Johnson & Johnson Innovative Medicine, Janssen-Cilag AG, Hochstrasse 201, 8200 Schaffhausen, Switzerland
| | - Eli Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, North Haugh, KY16 9ST St Andrews, U.K
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5
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Rani S, Aslam S, Lal K, Noreen S, Alsader KAM, Hussain R, Shirinfar B, Ahmed N. Electrochemical C-H/C-C Bond Oxygenation: A Potential Technology for Plastic Depolymerization. CHEM REC 2024; 24:e202300331. [PMID: 38063812 DOI: 10.1002/tcr.202300331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 11/23/2023] [Indexed: 03/10/2024]
Abstract
Herein, we provide eco-friendly and safely operated electrocatalytic methods for the selective oxidation directly or with water, air, light, metal catalyst or other mediators serving as the only oxygen supply. Heavy metals, stoichiometric chemical oxidants, or harsh conditions were drawbacks of earlier oxidative cleavage techniques. It has recently come to light that a crucial stage in the deconstruction of plastic waste and the utilization of biomass is the selective activation of inert C(sp3 )-C/H(sp3 ) bonds, which continues to be a significant obstacle in the chemical upcycling of resistant polyolefin waste. An appealing alternative to chemical oxidations using oxygen and catalysts is direct or indirect electrochemical conversion. An essential transition in the chemical and pharmaceutical industries is the electrochemical oxidation of C-H/C-C bonds. In this review, we discuss cutting-edge approaches to chemically recycle commercial plastics and feasible C-C/C-H bonds oxygenation routes for industrial scale-up.
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Affiliation(s)
- Sadia Rani
- Department of Chemistry, The Women University Multan, Multan, 60000, Pakistan
| | - Samina Aslam
- Department of Chemistry, The Women University Multan, Multan, 60000, Pakistan
| | - Kiran Lal
- Department of Chemistry, The Women University Multan, Multan, 60000, Pakistan
| | - Sobia Noreen
- Institute of Chemistry, University of Sargodha, Sargodha, 40100, Pakistan
| | | | - Riaz Hussain
- Department of Chemistry, University of Education Lahore, D.G. Khan Campus, 32200, Pakistan
| | - Bahareh Shirinfar
- West Herts College - University of Hertfordshire, Watford, WD17 3EZ, London, United Kingdom
| | - Nisar Ahmed
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, United Kingdom
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6
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Tan HR, Zhou X, Gong T, You H, Zheng Q, Zhao SY, Xuan W. Anderson-type polyoxometalate-based metal-organic framework as an efficient heterogeneous catalyst for selective oxidation of benzylic C-H bonds. RSC Adv 2024; 14:364-372. [PMID: 38173623 PMCID: PMC10759227 DOI: 10.1039/d3ra07120k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 12/11/2023] [Indexed: 01/05/2024] Open
Abstract
Oxidative transformation of benzylic C-H bonds into functional carbonyl groups under mild conditions represents an efficient method for the synthesis of aromatic carboxylic acids and ketones. Here we report a high-efficiency catalyst system constructed from an Anderson-type polyoxometalate-based metal-Organic framework (POMOF-1) and N-hydroxyphthalimide (NHPI) for selective oxidation of methylarenes and alkylarenes under 1 atm O2 atmosphere. POMOF-1 exerted a synergistic effect originating from the well-aligned Anderson {CrMo6} clusters and Cu centers within the framework, and this entailed good cooperation with NHPI to catalyze the selective oxidation. Accordingly, the reactions exhibit good tolerance and chemical selectivity for a wide range of substrates bearing diverse substituent groups, and the corresponding carboxylic acids and ketones were harvested in good yields under mild conditions. Mechanism study reveals that POMOF-1 worked synergistically with NPHI to activate the benzylic C-H bonds of substrates, which are sequentially oxidized by oxygen and HOO˙ to give rise to the products. This work may pave a way to design high-efficiency catalysts by integration of polyoxometalate-based materials with NPHI for challenging C-H activation.
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Affiliation(s)
- Hong-Ru Tan
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering, Donghua University Shanghai 201620 P. R. China
| | - Xiang Zhou
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University Shanghai 201620 P. R. China
| | - Tengfei Gong
- Jiaxing Jiayuan Inspection Technology Service Co., Ltd Building 2, No. 1403, Hongbo Road, Economic and Technological Development Zone Jiaxing City Zhejiang Province P. R. China
| | - Hanqi You
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering, Donghua University Shanghai 201620 P. R. China
| | - Qi Zheng
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University Shanghai 201620 P. R. China
| | - Sheng-Yin Zhao
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering, Donghua University Shanghai 201620 P. R. China
| | - Weimin Xuan
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering, Donghua University Shanghai 201620 P. R. China
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7
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Yang K, Feng T, Qiu Y. Organo-Mediator Enabled Electrochemical Deuteration of Styrenes. Angew Chem Int Ed Engl 2023; 62:e202312803. [PMID: 37698174 DOI: 10.1002/anie.202312803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 09/11/2023] [Accepted: 09/12/2023] [Indexed: 09/13/2023]
Abstract
Despite widespread use of the deuterium isotope effect, selective deuterium labeling of chemical molecules remains a major challenge. Herein, a facile and general electrochemically driven, organic mediator enabled deuteration of styrenes with deuterium oxide (D2 O) as the economical deuterium source was reported. Importantly, this transformation could be suitable for various electron rich styrenes mediated by triphenylphosphine (TPP). The reaction proceeded under mild conditions without transition-metal catalysts, affording the desired products in good yields with excellent D-incorporation (D-inc, up to >99 %). Mechanistic investigations by means of isotope labeling experiments and cyclic voltammetry tests provided sufficient support for this transformation. Notably, this method proved to be a powerful tool for late-stage deuteration of biorelevant compounds.
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Affiliation(s)
- Keming Yang
- 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
| | - 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
| | - 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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8
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Liu M, Feng T, Wang Y, Kou G, Wang Q, Wang Q, Qiu Y. Metal-free electrochemical dihydroxylation of unactivated alkenes. Nat Commun 2023; 14:6467. [PMID: 37833286 PMCID: PMC10575955 DOI: 10.1038/s41467-023-42106-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023] Open
Abstract
Herein, a metal-free electrochemical dihydroxylation of unactivated alkenes is described. The transformation proceeds smoothly under mild conditions with a broad range of unactivated alkenes, providing valuable and versatile dihydroxylated products in moderate to good yields without the addition of costly transition metals and stoichiometric amounts of chemical oxidants. Moreover, this method can be applied to a range of natural products and pharmaceutical derivatives, further demonstrating its synthetic utility. Mechanistic studies have revealed that iodohydrin and epoxide intermediate are formed during the reaction process.
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Affiliation(s)
- Min 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
| | - 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
| | - Yanwei 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
| | - Guangsheng Kou
- 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
| | - Qiuyan 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.
| | - Qian 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
| | - 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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9
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Wang Y, Dana S, Long H, Xu Y, Li Y, Kaplaneris N, Ackermann L. Electrochemical Late-Stage Functionalization. Chem Rev 2023; 123:11269-11335. [PMID: 37751573 PMCID: PMC10571048 DOI: 10.1021/acs.chemrev.3c00158] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Indexed: 09/28/2023]
Abstract
Late-stage functionalization (LSF) constitutes a powerful strategy for the assembly or diversification of novel molecular entities with improved physicochemical or biological activities. LSF can thus greatly accelerate the development of medicinally relevant compounds, crop protecting agents, and functional materials. Electrochemical molecular synthesis has emerged as an environmentally friendly platform for the transformation of organic compounds. Over the past decade, electrochemical late-stage functionalization (eLSF) has gained major momentum, which is summarized herein up to February 2023.
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Affiliation(s)
| | | | | | - Yang Xu
- Institut für Organische
und Biomolekulare Chemie and Wöhler Research Institute for
Sustainable Chemistry (WISCh), Georg-August-Universität, Göttingen 37077, Germany
| | - Yanjun Li
- Institut für Organische
und Biomolekulare Chemie and Wöhler Research Institute for
Sustainable Chemistry (WISCh), Georg-August-Universität, Göttingen 37077, Germany
| | - Nikolaos Kaplaneris
- Institut für Organische
und Biomolekulare Chemie and Wöhler Research Institute for
Sustainable Chemistry (WISCh), Georg-August-Universität, Göttingen 37077, Germany
| | - Lutz Ackermann
- Institut für Organische
und Biomolekulare Chemie and Wöhler Research Institute for
Sustainable Chemistry (WISCh), Georg-August-Universität, Göttingen 37077, Germany
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10
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Chen TS, Long H, Gao Y, Xu HC. Continuous Flow Electrochemistry Enables Practical and Site-Selective C-H Oxidation. Angew Chem Int Ed Engl 2023; 62:e202310138. [PMID: 37590086 DOI: 10.1002/anie.202310138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 08/08/2023] [Accepted: 08/17/2023] [Indexed: 08/18/2023]
Abstract
The selective oxygenation of ubiquitous C(sp3 )-H bonds remains a highly sought-after method in both academia and the chemical industry for constructing functionalized organic molecules. However, it is extremely challenging to selectively oxidize a certain C(sp3 )-H bond to afford alcohols due to the presence of multiple C(sp3 )-H bonds with similar strength and steric environment in organic molecules, and the alcohol products being prone to further oxidation. Herein, we present a practical and cost-efficient electrochemical method for the highly selective monooxygenation of benzylic C(sp3 )-H bonds using continuous flow reactors. The electrochemical reactions produce trifluoroacetate esters that are resistant to further oxidation but undergo facile hydrolysis during aqueous workup to form benzylic alcohols. The method exhibits a broad scope and exceptional site selectivity and requires no catalysts or chemical oxidants. Furthermore, the electrochemical method demonstrates excellent scalability by producing 115 g of one of the alcohol products. The high site selectivity of the electrochemical method originates from its unique mechanism to cleave benzylic C(sp3 )-H bonds through sequential electron/proton transfer, rather than the commonly employed hydrogen atom transfer (HAT).
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Affiliation(s)
- Tian-Sheng Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Hao Long
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Yuxing Gao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Hai-Chao Xu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
- Discipline of Intelligent Instrument and Equipment, Xiamen University, Xiamen, 361005, China
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11
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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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12
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Meger FS, Murphy JA. Recent Advances in C-H Functionalisation through Indirect Hydrogen Atom Transfer. Molecules 2023; 28:6127. [PMID: 37630379 PMCID: PMC10459052 DOI: 10.3390/molecules28166127] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 08/09/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
The functionalisation of C-H bonds has been an enormous achievement in synthetic methodology, enabling new retrosynthetic disconnections and affording simple synthetic equivalents for synthons. Hydrogen atom transfer (HAT) is a key method for forming alkyl radicals from C-H substrates. Classic reactions, including the Barton nitrite ester reaction and Hofmann-Löffler-Freytag reaction, among others, provided early examples of HAT. However, recent developments in photoredox catalysis and electrochemistry have made HAT a powerful synthetic tool capable of introducing a wide range of functional groups into C-H bonds. Moreover, greater mechanistic insights into HAT have stimulated the development of increasingly site-selective protocols. Site-selectivity can be achieved through the tuning of electron density at certain C-H bonds using additives, a judicious choice of HAT reagent, and a solvent system. Herein, we describe the latest methods for functionalizing C-H/Si-H/Ge-H bonds using indirect HAT between 2018-2023, as well as a critical discussion of new HAT reagents, mechanistic aspects, substrate scopes, and background contexts of the protocols.
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Affiliation(s)
- Filip S. Meger
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, 16 Avinguda dels Països Catalans, 43007 Tarragona, Catalonia, Spain
| | - John A. Murphy
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, UK
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13
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Li A, Li X, Ma F, Gao H, Li H. Cyclization of Azobenzenes Via Electrochemical Oxidation Induced Benzylic Radical Generation. Org Lett 2023; 25:5978-5983. [PMID: 37548915 DOI: 10.1021/acs.orglett.3c02099] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
An electrochemical oxidation-induced cyclization of ortho-alkyl-substituted azobenzenes has been developed. The direct electrochemical benzylic C-H functionalization with respect to azobenzenes could proceed in the absence of any catalyst or external chemical oxidant to afford a number of 2H-indazole derivatives in moderate to good yields. This protocol enables the reuse of the byproduct to the same 2H-indazoles, thus significantly reducing pollution discharge in synthetic chemistry.
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Affiliation(s)
- Anni Li
- Key Laboratory of Green and Precise Synthetic Chemistry, Ministry of Education, School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui, P. R. China
| | - Xiangyi Li
- Key Laboratory of Green and Precise Synthetic Chemistry, Ministry of Education, School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui, P. R. China
| | - Fang Ma
- Key Laboratory of Green and Precise Synthetic Chemistry, Ministry of Education, School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui, P. R. China
| | - Hui Gao
- Key Laboratory of Green and Precise Synthetic Chemistry, Ministry of Education, School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui, P. R. China
- Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, P. R. China
| | - Hongji Li
- Key Laboratory of Green and Precise Synthetic Chemistry, Ministry of Education, School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui, P. R. China
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14
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Zhang S, Findlater M. Electrochemically Driven Hydrogen Atom Transfer Catalysis: A Tool for C(sp 3)/Si-H Functionalization and Hydrofunctionalization of Alkenes. ACS Catal 2023; 13:8731-8751. [PMID: 37441236 PMCID: PMC10334887 DOI: 10.1021/acscatal.3c01221] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/27/2023] [Indexed: 07/15/2023]
Abstract
Electrochemically driven hydrogen atom transfer (HAT) catalysis provides a complementary approach for the transformation of redox-inactive substrates that would be inaccessible to conventional electron transfer (ET) catalysis. Moreover, electrochemically driven HAT catalysis could promote organic transformations with either hydrogen atom abstraction or donation as the key step. It provides a versatile and effective tool for the direct functionalization of C(sp3)-H/Si-H bonds and the hydrofunctionalization of alkenes. Despite these attractive properties, electrochemically driven HAT catalysis has been largely overlooked due to the lack of understanding of both the catalytic mechanism and how catalyst selection should occur. In this Review, we give an overview of the HAT catalysis applications in the direct C(sp3)-H/Si-H functionalization and hydrofunctionalization of alkenes. The mechanistic pathways, physical properties of the HAT mediators, and state-of-the-art examples are described and discussed.
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Affiliation(s)
- Sheng Zhang
- Institutes
of Physical Science and Information Technology, Key Laboratory of
Structure and Functional Regulation of Hybrid Materials of Ministry
of Education, Anhui University, Hefei, Anhui 230601, China
| | - Michael Findlater
- Department
of Chemistry and Biochemistry, University
of California Merced, Merced, California 95343, United States
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15
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Sitter JD, Lemus-Rivera EE, Vannucci AK. Insights into reactivity trends for electrochemical C-N bond formations. Org Biomol Chem 2023; 21:4290-4296. [PMID: 37158009 DOI: 10.1039/d3ob00236e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Electrochemical synthesis techniques are currently of great interest due to the possibility of synthesizing products while limiting reactant and energy input and providing potentially unique selectivity. Our group has previously reported the development of the "anion pool" synthesis method. As this is a new method for organic synthesis and the coupling of C-N bonds, it is important to understand the reactivity trends and limitations this method provides. In this report we explore the reactivity trends of a series of nitrogen-containing heterocycles under reductive electrochemical conditions. The results show that anionic nitrogen heterocycles are stable at room temperature in acetonitrile/electrolyte solutions up to a parent N-H pKa value up to 23. Addition of carbon electrophiles to solutions containing the electrochemically generated anionic nitrogen heterocycles led to the C-N cross-coupling reactivity. Product yields tracked linearly with the pKa value of the N-H bond of the heterocycles over 4 orders of acidity magnitude. Both benzylic halides and perfluorinated aromatics were found suitable for undergoing C-N cross-coupling with the anionic nitrogen heterocycles with product yields as high as 90%. It is also shown that the stability and reactivity of the anions are affected by the choice of electrolyte and temperature. Additionally, this procedure compares well to green chemistry processes in atom economy and PMI values.
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Affiliation(s)
- James D Sitter
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA.
| | - Edgar E Lemus-Rivera
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA.
| | - Aaron K Vannucci
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA.
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16
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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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17
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Ding Y, Wu J, Huang H. Carbonylative Formal Cycloaddition between Alkylarenes and Aldimines Enabled by Palladium-Catalyzed Double C-H Bond Activation. J Am Chem Soc 2023; 145:4982-4988. [PMID: 36821463 DOI: 10.1021/jacs.3c00004] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Double C-H bond activation can enable an expeditious reaction pathway to cyclic compounds, offering an efficient tool to synthesize valuable molecules. However, cyclization reaction enabled by double C-H bond activation at one carbon atom is nearly unknown. Herein, we report a carbonylative formal cycloaddition of alkylarenes with imines via double benzylic C-H bond activation at one carbon atom, allowing a straightforward synthesis of β-lactams from readily accessible alkylarenes and imines, which paves the way for developing an annulation reaction through double C-H bond activation at one carbon atom.
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Affiliation(s)
- Yongzheng Ding
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Chemistry, Center for Excellence in Molecular Synthesis of CAS, University of Science and Technology of China, Hefei, 230026, P. R. China
| | - Jianing Wu
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Chemistry, Center for Excellence in Molecular Synthesis of CAS, University of Science and Technology of China, Hefei, 230026, P. R. China
| | - Hanmin Huang
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Chemistry, Center for Excellence in Molecular Synthesis of CAS, University of Science and Technology of China, Hefei, 230026, P. R. China.,Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China
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18
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Bai F, Wang N, Bai Y, Ma X, Gu C, Dai B, Chen J. NHPI-Mediated Electrochemical α-Oxygenation of Amides to Benzimides. J Org Chem 2023. [PMID: 36866582 DOI: 10.1021/acs.joc.2c02700] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
This report describes a mild electrochemical α-oxygenation of a wide range of linear and cyclic benzamides mediated by N-hydroxyphthalimide (NHPI) in an undivided cell using O2 as the oxygen source and 2,4,6-trimethylpyridine perchlorate as an electrolyte. The radical scavenger experiment and the 18O labeling experiment were carried out, which indicated the involvement of a radical pathway and suggested O2 as an oxygen source in the imides, respectively.
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Affiliation(s)
- Fang Bai
- State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, School of Chemistry and Chemical Engineering, Shihezi University, Xinjiang Uygur Autonomous Region 832000, China
| | - Ning Wang
- State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, School of Chemistry and Chemical Engineering, Shihezi University, Xinjiang Uygur Autonomous Region 832000, China
| | - Yinshan Bai
- State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, School of Chemistry and Chemical Engineering, Shihezi University, Xinjiang Uygur Autonomous Region 832000, China
| | - Xiaowei Ma
- State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, School of Chemistry and Chemical Engineering, Shihezi University, Xinjiang Uygur Autonomous Region 832000, China
| | - Chengzhi Gu
- State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, School of Chemistry and Chemical Engineering, Shihezi University, Xinjiang Uygur Autonomous Region 832000, China
| | - Bin Dai
- State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, School of Chemistry and Chemical Engineering, Shihezi University, Xinjiang Uygur Autonomous Region 832000, China
| | - Jianpeng Chen
- Hami Shuoyuan Chemical Co., Ltd, Xinjiang Uygur Autonomous Region 832000, China
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19
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Liu XH, Yu HY, Huang JY, Zhou XT, Xue C, Ji HB. Time-resolved EPR revealed C(sp 3)–H activation through a photo-enhanced phthalimide- N-oxyl (PINO) radical. Chem Commun (Camb) 2023; 59:243-246. [DOI: 10.1039/d2cc05906a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The time-resolved EPR technique under operando photochemical conditions as an efficient strategy to investigate the fast formation of abundant long-lived PINO radicals and their activation of the C(sp3)–H reaction is reported.
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Affiliation(s)
- Xiao-Hui Liu
- Fine Chemical Industry Research Institute, School of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China
| | - Hai-Yang Yu
- Fine Chemical Industry Research Institute, School of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China
| | - Jia-Ying Huang
- Fine Chemical Industry Research Institute, School of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China
| | - Xian-Tai Zhou
- Fine Chemical Industry Research Institute, School of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China
| | - Can Xue
- Fine Chemical Industry Research Institute, School of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, China
| | - Hong-Bing Ji
- Fine Chemical Industry Research Institute, School of Chemistry, Sun Yat-sen University, Guangzhou, 510275, China
- Advanced Energy Science and Technology Guangdong Laboratory, Huizhou, Guangdong, 516003, China
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20
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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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