1
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Atkins AP, Dean AC, Lennox AJJ. Benzylic C(sp 3)-H fluorination. Beilstein J Org Chem 2024; 20:1527-1547. [PMID: 39015617 PMCID: PMC11250007 DOI: 10.3762/bjoc.20.137] [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: 04/24/2024] [Accepted: 06/26/2024] [Indexed: 07/18/2024] Open
Abstract
The selective fluorination of C(sp3)-H bonds is an attractive target, particularly for pharmaceutical and agrochemical applications. Consequently, over recent years much attention has been focused on C(sp3)-H fluorination, and several methods that are selective for benzylic C-H bonds have been reported. These protocols operate via several distinct mechanistic pathways and involve a variety of fluorine sources with distinct reactivity profiles. This review aims to give context to these transformations and strategies, highlighting the different tactics to achieve fluorination of benzylic C-H bonds.
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Affiliation(s)
| | - Alice C Dean
- University of Bristol, School of Chemistry, Bristol, BS8 1TS, U.K.
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2
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Jesani MH, Schwarz M, Kim S, Evans FL, White A, Browning A, Abrams R, Clayden J. Selective Defluorination of Trifluoromethyl Substituents by Conformationally Induced Remote Substitution. Angew Chem Int Ed Engl 2024; 63:e202403477. [PMID: 38587304 DOI: 10.1002/anie.202403477] [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: 02/19/2024] [Revised: 03/28/2024] [Accepted: 04/02/2024] [Indexed: 04/09/2024]
Abstract
The selective reduction of an aromatic trifluoromethyl substituent to a difluoromethyl substituent may be achieved by base-promoted elimination to form a difluoro-p-quinomethide which is trapped by an intramolecular nucleophile. High yields are obtained when the nucleophilic trap entails the conformationally favoured cyclisation of an aminoisobutyric acid (Aib) derivative. The resulting cyclised difluoromethyl-substituted arylimidazolidinone products are readily converted to versatile difluoromethyl-substituted aldehydes by reduction and hydrolysis. Defluorination is successful on a range of benzenoid (both para and ortho CF3-substituted) and heterocyclic substrates. Double defluorination may likewise be achieved sequentially, or in a single step, from an Aib dipeptide derivative.
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Affiliation(s)
- Mehul H Jesani
- School of Chemistry, University of Bristol Cantock's Close, Bristol, BS8 1TS, UK
| | - Maria Schwarz
- School of Chemistry, University of Bristol Cantock's Close, Bristol, BS8 1TS, UK
| | - Shiwhu Kim
- School of Chemistry, University of Bristol Cantock's Close, Bristol, BS8 1TS, UK
| | - Finlay L Evans
- School of Chemistry, University of Bristol Cantock's Close, Bristol, BS8 1TS, UK
| | - Alexander White
- School of Chemistry, University of Bristol Cantock's Close, Bristol, BS8 1TS, UK
| | - Alex Browning
- School of Chemistry, University of Bristol Cantock's Close, Bristol, BS8 1TS, UK
| | - Roman Abrams
- School of Chemistry, University of Bristol Cantock's Close, Bristol, BS8 1TS, UK
| | - Jonathan Clayden
- School of Chemistry, University of Bristol Cantock's Close, Bristol, BS8 1TS, UK
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3
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Xu J, Liu B. Metal Free Functionalization of Saturated Heterocycles with Vinylarenes and Pyridine Enabled by Photocatalytic Hydrogen Atom Transfer. Chemistry 2024; 30:e202400612. [PMID: 38566284 DOI: 10.1002/chem.202400612] [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: 02/16/2024] [Revised: 03/25/2024] [Accepted: 04/01/2024] [Indexed: 04/04/2024]
Abstract
Saturated heterocycles are important class of structural scaffolds in small-molecule drugs, natural products, and synthetic intermediates. Here, we disclosed a metal free, mild, and scalable functionalization of saturated heterocycles using vinylarenes as a linchpin approach. Key to success of this transformation is the employing of simple and cheap benzophenone as a hydrogen atom transfer (HAT) catalyst. This operationally robust process was used for the making of diverse functionalized saturated heterocycles. Furthermore, aldehydes, alkane, and alcohol have been functionalized under the optimized conditions. The potential pharmaceutical utility of the procedure has also been demonstrated by late-stage functionalization of bioactive natural compounds and pharmaceutical molecules. Initial mechanism studies and control experiments were performed to elucidate the mechanism of the reactions.
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Affiliation(s)
- Junhua Xu
- School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi, 330031, People's Republic of China
| | - Bin Liu
- School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi, 330031, People's Republic of China
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4
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Zhang F, Zhang G, Zhou Q, Bian T, Zhou L, Zhang Z. Hybrid Palladium-Catalyzed Intramolecular Carboamination of Conjugated Dienes: Synthesis of Functionalized Pyrrolidines via Selective Trifluoromethylarene Defluorination. J Org Chem 2024. [PMID: 38808763 DOI: 10.1021/acs.joc.4c00447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
The incorporation of difluoromethylene groups into aza-heterocycles represents a compelling yet underexplored avenue in contemporary chemical research. In this study, we unveil a hybrid palladium-catalyzed intramolecular gem-difluoroalkylamination of conjugated dienes, providing a versatile approach to the synthesis of diverse functionalized pyrrolidines. Noteworthy features include mild reaction conditions and a remarkable tolerance toward various functional groups. Additionally, the use of alkyl iodides as electrophiles facilitates the generation of the corresponding alkylamination products. Control experiments support a proposed hybrid palladium-catalyzed radical-polar crossover pathway, offering insights into the underlying chemical processes governing this transformation.
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Affiliation(s)
- Feijie Zhang
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Materials Science, Zhejiang Normal University, 688 Yingbin Road, Jinhua 321004, P. R. China
| | - Guocong Zhang
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Materials Science, Zhejiang Normal University, 688 Yingbin Road, Jinhua 321004, P. R. China
| | - Qixin Zhou
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Materials Science, Zhejiang Normal University, 688 Yingbin Road, Jinhua 321004, P. R. China
| | - Tiancen Bian
- Department of Chemistry, University of Hawai'i at Ma̅noa, Honolulu, Hawaii 96822-2217, United States
| | - Liejin Zhou
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Materials Science, Zhejiang Normal University, 688 Yingbin Road, Jinhua 321004, P. R. China
| | - Zuxiao Zhang
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Materials Science, Zhejiang Normal University, 688 Yingbin Road, Jinhua 321004, P. R. China
- Department of Chemistry, University of Hawai'i at Ma̅noa, Honolulu, Hawaii 96822-2217, United States
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5
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Li S, Wei W, Chi K, Ferguson CTJ, Zhao Y, Zhang KAI. Promoting Photocatalytic Direct C-H Difluoromethylation of Heterocycles using Synergistic Dual-Active-Centered Covalent Organic Frameworks. J Am Chem Soc 2024; 146:12386-12394. [PMID: 38500309 PMCID: PMC11082899 DOI: 10.1021/jacs.3c12880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 03/04/2024] [Accepted: 03/05/2024] [Indexed: 03/20/2024]
Abstract
Difluoromethylation reactions are increasingly important for the creation of fluorine-containing heterocycles, which are core groups in a diverse range of biologically and pharmacologically active ingredients. Ideally, this typically challenging reaction could be performed photocatalytically under mild conditions. To achieve this separation of redox processes would be required for the efficient generation of difluoromethyl radicals and the reduction of oxygen. A covalent organic framework photocatalytic material was, therefore, designed with dual reactive centers. Here, anthracene was used as a reduction site and benzothiadiazole was used as an oxidation site, distributed in a tristyryl triazine framework. Efficient charge separation was ensured by the superior electron-donating and -accepting abilities of the dual centers, creating long-lived photogenerated electron-hole pairs. Photocatalytic difluoromethylation of 16 compounds with high yields and remarkable functional group tolerance was demonstrated; compounds included bioactive molecules such as xanthine and uracil. The structure-function relationship of the dual-active-center photocatalyst was investigated through electron spin resonance, femtosecond transient absorption spectroscopy, and density functional theory calculations.
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Affiliation(s)
- Sizhe Li
- Department
of Materials Science, Fudan University, 200433 Shanghai, P. R. China
| | - Wenxin Wei
- Department
of Materials Science, Fudan University, 200433 Shanghai, P. R. China
| | - Kai Chi
- Department
of Materials Science, Fudan University, 200433 Shanghai, P. R. China
| | - Calum T. J. Ferguson
- Max
Planck Institute for Polymer Research, 55128 Mainz, Germany
- School
of Chemistry, University of Birmingham, University Road W, Birmingham B15 2TT, United Kingdom
| | - Yan Zhao
- Department
of Materials Science, Fudan University, 200433 Shanghai, P. R. China
| | - Kai A. I. Zhang
- Department
of Materials Science, Fudan University, 200433 Shanghai, P. R. China
- Max
Planck Institute for Polymer Research, 55128 Mainz, Germany
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6
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Hu X, Cheng-Sánchez I, Kong W, Molander GA, Nevado C. Nickel-catalysed enantioselective alkene dicarbofunctionalization enabled by photochemical aliphatic C-H bond activation. Nat Catal 2024; 7:655-665. [PMID: 38947227 PMCID: PMC11208155 DOI: 10.1038/s41929-024-01153-0] [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: 06/15/2023] [Accepted: 03/25/2024] [Indexed: 07/02/2024]
Abstract
The development of novel strategies to rapidly construct complex chiral molecules from readily available feedstocks is a long-term pursuit in the chemistry community. Radical-mediated alkene difunctionalizations represent an excellent platform towards this goal. However, asymmetric versions remain highly challenging, and more importantly, examples featuring simple hydrocarbons as reaction partners are elusive. Here we report an asymmetric three-component alkene dicarbofunctionalization capitalizing on the direct activation of C(sp 3)-H bonds through the combination of photocatalysed hydrogen atom transfer and nickel catalysis. This protocol provides an efficient platform for installing two vicinal carbon-carbon bonds across alkenes in an atom-economic fashion, providing a wide array of high-value chiral α-aryl/alkenyl carbonyls and phosphonates, as well as 1,1-diarylalkanes from ubiquitous alkane, ether and alcohol feedstocks. This method exhibits operational simplicity, broad substrate scope and excellent regioselectivity, chemoselectivity and enantioselectivity. The compatibility with bioactive motifs and expedient synthesis of pharmaceutically relevant molecules highlight the synthetic potential of this protocol.
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Affiliation(s)
- Xia Hu
- Department of Chemistry, University of Zurich, Zurich, Switzerland
| | | | - Wangqing Kong
- The Institute for Advanced Studies, Wuhan University, Wuhan, China
| | - Gary A. Molander
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA USA
| | - Cristina Nevado
- Department of Chemistry, University of Zurich, Zurich, Switzerland
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7
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Chakrabarti K, Wade Wolfe MM, Guo S, Tucker JW, Lee J, Szymczak NK. A metal-free strategy to construct fluoroalkyl-olefin linkages using fluoroalkanes. Chem Sci 2024; 15:1752-1757. [PMID: 38303957 PMCID: PMC10829021 DOI: 10.1039/d3sc05616c] [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: 10/21/2023] [Accepted: 12/21/2023] [Indexed: 02/03/2024] Open
Abstract
We present a metal-free strategy to access fluoroalkyl-olefin linkages from fluoroalkane precursors and vinyl-pinacol boronic ester (BPin) reagents. This reaction sequence is templated by the boron reagent, which induces C-C bond formation upon oxidation. We developed this strategy into a one-pot synthetic protocol using RCF2H precursors directly with vinyl-BPin reagents in the presence of a Brønsted base, which tolerated oxygen- and nitrogen-containing heterocycles, and aryl halogens. We also found that HCF3 (HCF-23; a byproduct of the Teflon industry) and CH2F2 (HCF-32; a low-cost refrigerant) are amenable to this protocol, representing distinct strategies to generate RCF2H and RCF3 molecules. Finally, we demonstrate that the vinyldifluoromethylene products can be readily derivatized, representing an avenue for late-stage modification after installing the fluoroalkyl unit.
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Affiliation(s)
- Kaushik Chakrabarti
- Department of Chemistry, University of Michigan, 930 N. University Ann Arbor Michigan 48109 USA
| | - Michael M Wade Wolfe
- Department of Chemistry, University of Michigan, 930 N. University Ann Arbor Michigan 48109 USA
| | - Shuo Guo
- College of Chemistry and Chemical Engineering, Inner Mongolia University Hohhot 010021 P.R. China
| | - Joseph W Tucker
- Medicine Design, Pfizer Inc. Eastern Point Rd Groton CT 06340 USA
| | - Jisun Lee
- Medicine Design, Pfizer Inc. Eastern Point Rd Groton CT 06340 USA
| | - Nathaniel K Szymczak
- Department of Chemistry, University of Michigan, 930 N. University Ann Arbor Michigan 48109 USA
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8
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Atkins AP, Chaturvedi AK, Tate JA, Lennox AJJ. Pulsed electrolysis: enhancing primary benzylic C(sp 3)-H nucleophilic fluorination. Org Chem Front 2024; 11:802-808. [PMID: 38298566 PMCID: PMC10825853 DOI: 10.1039/d3qo01865b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 12/09/2023] [Indexed: 02/02/2024]
Abstract
Electrosynthesis is an efficient and powerful tool for the generation of elusive reactive intermediates. The application of alternative electrolysis waveforms provides a new level of control for dynamic redox environments. Herein, we demonstrate that pulsed electrolysis provides a favourable environment for the generation and fluorination of highly unstable primary benzylic cations from C(sp3)-H bonds. By introduction of a toff period, we propose this waveform modulates the electrical double layer to improve mass transport and limit over-oxidation.
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Affiliation(s)
- Alexander P Atkins
- School of Chemistry, University of Bristol Cantock's Close BS8 1TS Bristol UK
| | - Atul K Chaturvedi
- School of Chemistry, University of Bristol Cantock's Close BS8 1TS Bristol UK
| | - Joseph A Tate
- Jealott's Hill International Research Centre, Syngenta Jealott's Hill Bracknell RG426EY UK
| | - Alastair J J Lennox
- School of Chemistry, University of Bristol Cantock's Close BS8 1TS Bristol UK
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9
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Bian KJ, Nemoto D, Chen XW, Kao SC, Hooson J, West JG. Photocatalytic, modular difunctionalization of alkenes enabled by ligand-to-metal charge transfer and radical ligand transfer. Chem Sci 2023; 15:124-133. [PMID: 38131080 PMCID: PMC10732012 DOI: 10.1039/d3sc05231a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 11/09/2023] [Indexed: 12/23/2023] Open
Abstract
Ligand-to-metal charge transfer (LMCT) is a mechanistic strategy that provides a powerful tool to access diverse open-shell species using earth abundant elements and has seen tremendous growth in recent years. However, among many reaction manifolds driven by LMCT reactivity, a general and catalytic protocol for modular difunctionalization of alkenes remains unknown. Leveraging the synergistic cooperation of iron-catalyzed ligand-to-metal charge transfer and radical ligand transfer (RLT), here we report a photocatalytic, modular difunctionalization of alkenes using inexpensive iron salts catalytically to function as both radical initiator and terminator. Additionally, strategic use of a fluorine atom transfer reagent allows for general fluorochlorination of alkenes, providing the first example of interhalogen compound formation using earth abundant element photocatalysis. Broad scope, mild conditions and versatility in converting orthogonal nucleophiles (TMSN3 and NaCl) directly into corresponding open-shell radical species are demonstrated in this study, providing a robust means towards accessing vicinal diazides and homo-/hetero-dihalides motifs catalytically. These functionalities are important precursors/intermediates in medicinal and material chemistry. Preliminary mechanistic studies support the radical nature of these transformations, disclosing the tandem LMCT/RLT as a powerful reaction manifold in catalytic olefin difunctionalization.
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Affiliation(s)
- Kang-Jie Bian
- Department of Chemistry, Rice University 6100 Main St MS 602 Houston TX 77005 USA
| | - David Nemoto
- Department of Chemistry, Rice University 6100 Main St MS 602 Houston TX 77005 USA
| | - Xiao-Wei Chen
- Department of Chemistry, Rice University 6100 Main St MS 602 Houston TX 77005 USA
| | - Shih-Chieh Kao
- Department of Chemistry, Rice University 6100 Main St MS 602 Houston TX 77005 USA
| | - James Hooson
- Department of Chemistry, Rice University 6100 Main St MS 602 Houston TX 77005 USA
| | - Julian G West
- Department of Chemistry, Rice University 6100 Main St MS 602 Houston TX 77005 USA
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10
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Huang J, Gao Q, Zhong T, Chen S, Lin W, Han J, Xie J. Photoinduced copper-catalyzed C-N coupling with trifluoromethylated arenes. Nat Commun 2023; 14:8292. [PMID: 38092783 PMCID: PMC10719352 DOI: 10.1038/s41467-023-44097-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023] Open
Abstract
Selective defluorinative functionalization of trifluoromethyl group (-CF3) is an attractive synthetic route to the pharmaceutically privileged fluorine-containing moiety. Herein, we report a strategy based on photoexcited copper catalysis to activate the C-F bond of di- or trifluoromethylated arenes for divergent radical C-N coupling with carbazoles and aromatic amines. The use of different ligands can tune the reaction products diversity. A range of substituted, structurally diverse α,α-difluoromethylamines can be obtained from trifluoromethylated arenes via defluorinative C-N coupling with carbazoles, while an interesting double defluorinative C-N coupling is ready for difluoromethylated arenes. Based on this success, a carbazole-centered PNP ligand is designed to be an optimal ligand, enabling a copper-catalyzed C-N coupling for the construction of imidoyl fluorides from aromatic amines through double C-F bond functionalization. Interestingly, a 1,2-difluoroalkylamination strategy of styrenes is also developed, delivering γ,γ-difluoroalkylamines, a bioisostere to β-aminoketones, in synthetically useful yields. The DFT studies reveal an inner-sphere electron transfer mechanism for Cu-catalyzed selective activation of C(sp3)-F bonds.
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Affiliation(s)
- Jun Huang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Qi Gao
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Tao Zhong
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Shuai Chen
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Wei Lin
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
- School of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou, 213001, China
| | - Jie Han
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
| | - Jin Xie
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
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11
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Yuan J, Shen L, Guo N, Yin Y, Yang P, Yang L, Xiao Y, Zhang S. Visible-Light-Induced Cascade Cyclization of 1-Acryloyl-2-cyanoindole: Access of Difluoroalkylated Pyrrolo[1,2- a]indolediones. J Org Chem 2023; 88:16598-16608. [PMID: 37948397 DOI: 10.1021/acs.joc.3c02183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
An effective method for accessing diverse difluoroalkylated pyrrolo[1,2-a]indolediones via visible-light-induced PhI(OAc)2-promoted cascade difluoroalkylation/cyclization reaction under mild conditions has been established. This method is noteworthy for its use of DMSO-H2O as a green medium at room temperature and avoidance of photocatalysts. The reactions are straightforward to execute and convenient to expand on, provide good to excellent yields, and have good functional group tolerance.
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Affiliation(s)
- Jinwei Yuan
- School of Chemistry & Chemical Engineering, Henan University of Technology, Zhengzhou 450001, P. R. China
| | - Lu Shen
- School of Chemistry & Chemical Engineering, Henan University of Technology, Zhengzhou 450001, P. R. China
| | - Na Guo
- College of Advanced Interdisciplinary Science and Technology, Henan University of Technology, Zhengzhou 450001, P. R. China
| | - Yanli Yin
- College of Advanced Interdisciplinary Science and Technology, Henan University of Technology, Zhengzhou 450001, P. R. China
| | - Pengyuan Yang
- School of Chemistry & Chemical Engineering, Henan University of Technology, Zhengzhou 450001, P. R. China
| | - Liangru Yang
- School of Chemistry & Chemical Engineering, Henan University of Technology, Zhengzhou 450001, P. R. China
| | - Yongmei Xiao
- School of Chemistry & Chemical Engineering, Henan University of Technology, Zhengzhou 450001, P. R. China
| | - Shouren Zhang
- Henan Key Laboratory of Nanocomposites and Applications, Institute of Nanostructured Functional Materials, Huanghe Science and Technology College, Zhengzhou 450006, P. R. China
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12
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Holt E, Ruskin J, Garrison NG, Vemulapalli S, Lam W, Kiame N, Henriquez N, Borukhova F, Williams J, Dudding T, Lectka T. Photoactivated Pyridine Directed Fluorination through Hydrogen Atom Transfer. J Org Chem 2023. [PMID: 38033293 DOI: 10.1021/acs.joc.3c02146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
We have established hydrogen atom transfer (HAT) as the key player in a directed, photopromoted fluorination of pyridylic groups. The Lewis basic pyridyl nitrogen directs amine radical dication propagated HAT and Selectfluor fluorination of various ortho substituents in a highly regioselective manner with little to no side product formation. A variety of pyridines and quinolines were employed to showcase the directing capability of the nitrogen atom. Additionally, both experimental and computational data are provided that illuminate how this mechanism differs from and complements prior work in the area.
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Affiliation(s)
- Eric Holt
- Department of Chemistry, Johns Hopkins University, 3400 North Charles St., Baltimore, Maryland 21218, United States
| | - Jonah Ruskin
- Department of Chemistry, Johns Hopkins University, 3400 North Charles St., Baltimore, Maryland 21218, United States
| | - Nathaniel G Garrison
- Department of Chemistry, Johns Hopkins University, 3400 North Charles St., Baltimore, Maryland 21218, United States
| | - Srini Vemulapalli
- Department of Chemistry, Brock University, St. Catharines, Ontario L2S3A1, Canada
| | - Winson Lam
- Department of Chemistry, Johns Hopkins University, 3400 North Charles St., Baltimore, Maryland 21218, United States
| | - Neil Kiame
- Department of Chemistry, Johns Hopkins University, 3400 North Charles St., Baltimore, Maryland 21218, United States
| | - Nicolas Henriquez
- Department of Chemistry, Johns Hopkins University, 3400 North Charles St., Baltimore, Maryland 21218, United States
| | - Fanny Borukhova
- Department of Chemistry, Johns Hopkins University, 3400 North Charles St., Baltimore, Maryland 21218, United States
| | - Jack Williams
- Department of Chemistry, Johns Hopkins University, 3400 North Charles St., Baltimore, Maryland 21218, United States
| | - Travis Dudding
- Department of Chemistry, Brock University, St. Catharines, Ontario L2S3A1, Canada
| | - Thomas Lectka
- Department of Chemistry, Johns Hopkins University, 3400 North Charles St., Baltimore, Maryland 21218, United States
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13
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Kitahara T, Tagami Y, Haga Y, Fustero S, Sugiishi T, Amii H. Alkylation and silylation of α-fluorobenzyl anion intermediates. Org Biomol Chem 2023; 21:9210-9215. [PMID: 37961788 DOI: 10.1039/d3ob01586f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Simple α-fluorobenzyl anions reacted with electrophiles such as non-activated alkyl halides and chlorotrimethylsilane. Upon treatment with LTMP as the base, fluoromethylbenzenes took part in the formation of α-monofluorobenzyl anions without stabilizing o-substituents. Furthermore, the resulting α-silyl fluoromethylbenzenes reacted with electrophiles such as acetophenone and benzaldehyde in the presence of cesium fluoride to form α-fluorobenzylated alcohols.
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Affiliation(s)
- Taku Kitahara
- Division of Molecular Science, Graduate School of Science and Technology, 1-5-1, Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
| | - Yuta Tagami
- Division of Molecular Science, Graduate School of Science and Technology, 1-5-1, Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
| | - Yuto Haga
- Division of Molecular Science, Graduate School of Science and Technology, 1-5-1, Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
| | - Santos Fustero
- Departamento de Química Orgánica, Facultad de Farmacia, Universitat de València, Vicente Andrés Estelles s/n, C.P.: 46100 Burjassot, Valencia, Spain
| | - Tsuyuka Sugiishi
- Division of Molecular Science, Graduate School of Science and Technology, 1-5-1, Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
| | - Hideki Amii
- Division of Molecular Science, Graduate School of Science and Technology, 1-5-1, Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
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14
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Dong X, Liu X, Wang L, Zhang Y, Li J, Tian L, Zhao Y. Catalyst-Free gem-Difluorination/Spirocyclization of Indole-2-carboxamides: Synthesis of C2-Spiroindoline Derivatives. Org Lett 2023. [PMID: 38014899 DOI: 10.1021/acs.orglett.3c03906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
A catalyst-free gem-difluorination/spirocyclization reaction has been successfully developed for the synthesis of gem-difluorinated C2-spiroindoline derivatives from indole-2-carboxamides. The resulting gem-difluorinated C2-spiroindolines can be easily converted into 2-spiropseudoindoxyls through hydrolysis. This method offers the benefits of simple operation, convenient access to raw materials, and mild conditions. Dual function of Selectfluor in this reaction is noteworthy as it can serve as both a fluorinating agent and an alkaline accelerator precursor.
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Affiliation(s)
- Xiaotong Dong
- Key Laboratory of Life-Organic Analysis of Shandong Province, Key Laboratory of Green Natural Products and Pharmaceutical Intermediates in Universities of Shandong Province, Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu City, Shandong Province 273165, P. R. China
| | - Xiaonuo Liu
- Key Laboratory of Life-Organic Analysis of Shandong Province, Key Laboratory of Green Natural Products and Pharmaceutical Intermediates in Universities of Shandong Province, Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu City, Shandong Province 273165, P. R. China
| | - Lei Wang
- Key Laboratory of Life-Organic Analysis of Shandong Province, Key Laboratory of Green Natural Products and Pharmaceutical Intermediates in Universities of Shandong Province, Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu City, Shandong Province 273165, P. R. China
| | - Yixuan Zhang
- Key Laboratory of Life-Organic Analysis of Shandong Province, Key Laboratory of Green Natural Products and Pharmaceutical Intermediates in Universities of Shandong Province, Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu City, Shandong Province 273165, P. R. China
| | - Jiale Li
- Key Laboratory of Life-Organic Analysis of Shandong Province, Key Laboratory of Green Natural Products and Pharmaceutical Intermediates in Universities of Shandong Province, Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu City, Shandong Province 273165, P. R. China
| | - Laijin Tian
- Key Laboratory of Life-Organic Analysis of Shandong Province, Key Laboratory of Green Natural Products and Pharmaceutical Intermediates in Universities of Shandong Province, Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu City, Shandong Province 273165, P. R. China
| | - Yulei Zhao
- Key Laboratory of Life-Organic Analysis of Shandong Province, Key Laboratory of Green Natural Products and Pharmaceutical Intermediates in Universities of Shandong Province, Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu City, Shandong Province 273165, P. R. China
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15
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Festa AA, Storozhenko OA, Voskressensky LG, Van der Eycken EV. Visible light-mediated halogenation of organic compounds. Chem Soc Rev 2023. [PMID: 37975853 DOI: 10.1039/d3cs00366c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
The use of visible light and photoredox catalysis emerged as a powerful and sustainable tool for organic synthesis, showing high value for distinctly different ways of bond creation. Halogenated compounds are the cornerstone of contemporary organic synthesis: it is almost impossible to develop a route towards a pharmaceutical reagent, agrochemical, natural product, etc. without the involvement of halogen-containing intermediates. Moreover, the halogenated derivatives as final products became indispensable for drug discovery and materials science. The idea of this review is to understand and summarise the impact of visible light-promoted chemistry on halogenation and halofunctionalisation reactions.
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Affiliation(s)
- Alexey A Festa
- Peoples' Friendship University of Russia (RUDN University), Miklukho-Maklaya st. 6, Moscow, 117198, Russian Federation.
| | - Olga A Storozhenko
- Peoples' Friendship University of Russia (RUDN University), Miklukho-Maklaya st. 6, Moscow, 117198, Russian Federation.
| | - Leonid G Voskressensky
- Peoples' Friendship University of Russia (RUDN University), Miklukho-Maklaya st. 6, Moscow, 117198, Russian Federation.
| | - Erik V Van der Eycken
- Peoples' Friendship University of Russia (RUDN University), Miklukho-Maklaya st. 6, Moscow, 117198, Russian Federation.
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven), Celestijnenlaan 200F, B-3001, Leuven, Belgium
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16
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Chen CL, Wang HY, Weng ZZ, Long LS, Zheng LS, Kong XJ. Uranyl Polyoxotungstate Cluster for Visible-Light-Driven Heterogeneous C-H Selective Fluorination. Inorg Chem 2023; 62:17041-17045. [PMID: 37819767 DOI: 10.1021/acs.inorgchem.3c02531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
The selective fluorination of C-H bonds at room temperature using heterogeneous visible-light catalysts is both interesting and challenging. Herein, we present the heterogeneous sandwich-type structure uranyl-polyoxotungstate cluster Na17{Na@[(SbW9O33)2(UO2)6(PO3OH)6]}·46H2O (denoted as U6P6) to regulate the selective fluorination of the C-H bond under visible light and room temperature. This is the first report in which uranyl participates in the fluorination reaction in the form of an insoluble substance. U6P6 is capable of the effective selective fluorination of cycloalkanes and the recyclability of the photocatalyst due to the synergistic effect of multiple uranyl (UO2)2+ and the insolubility of organic reagents of polyoxotungstate. In situ electron paramagnetic resonance spectroscopy captured the generation of cycloalkane radicals during the photoreaction, confirming the mechanism of direct hydrogen atom transfer.
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Affiliation(s)
- Chao-Long Chen
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surface and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen,361005, China
| | - Hai-Ying Wang
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surface and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen,361005, China
| | - Zhen-Zhang Weng
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surface and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen,361005, China
| | - La-Sheng Long
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surface and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen,361005, China
| | - Lan-Sun Zheng
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surface and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen,361005, China
| | - Xiang-Jian Kong
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surface and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen,361005, China
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17
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Wang M, Rowshanpour R, Guan L, Ruskin J, Nguyen PM, Wang Y, Zhang QA, Liu R, Ling B, Woltornist R, Stephens AM, Prasad A, Dudding T, Lectka T, Pitts CR. Competition between C-C and C-H Bond Fluorination: A Continuum of Electron Transfer and Hydrogen Atom Transfer Mechanisms. J Am Chem Soc 2023; 145:22442-22455. [PMID: 37791901 DOI: 10.1021/jacs.3c06477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
In 2015, we reported a photochemical method for directed C-C bond cleavage/radical fluorination of relatively unstrained cyclic acetals using Selectfluor and catalytic 9-fluorenone. Herein, we provide a detailed mechanistic study of this reaction, during which it was discovered that the key electron transfer step proceeds through substrate oxidation from a Selectfluor-derived N-centered radical intermediate (rather than through initially suspected photoinduced electron transfer). This finding led to proof of concept for two new methodologies, demonstrating that unstrained C-C bond fluorination can also be achieved under chemical and electrochemical conditions. Moreover, as C-C and C-H bond fluorination reactions are both theoretically possible on 2-aryl-cycloalkanone acetals and would involve the same reactive intermediate, we studied the competition between single-electron transfer (SET) and apparent hydrogen-atom transfer (HAT) pathways in acetal fluorination reactions using density functional theory. Finally, these analyses were applied more broadly to other classes of C-H and C-C bond fluorination reactions developed over the past decade, addressing the feasibility of SET processes masquerading as HAT in C-H fluorination literature.
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Affiliation(s)
- Muyuan Wang
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Rozhin Rowshanpour
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way St. Catharines, Ontario L2S 3A1, Canada
| | - Liangyu Guan
- BayRay Innovation Center, Shenzhen Bay Laboratory, Shenzhen 51832, China
| | - Jonah Ruskin
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Phuong Minh Nguyen
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Yuang Wang
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Qinze Arthur Zhang
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Ran Liu
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Bill Ling
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Ryan Woltornist
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Alexander M Stephens
- Department of Chemistry, University of California Davis, 1 Shields Avenue, Davis, California 95616, United States
| | - Aarush Prasad
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Travis Dudding
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way St. Catharines, Ontario L2S 3A1, Canada
| | - Thomas Lectka
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Cody Ross Pitts
- Department of Chemistry, University of California Davis, 1 Shields Avenue, Davis, California 95616, United States
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18
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Wang X, Zhang X, Xue L, Wang Q, You F, Dai L, Wu J, Kramer S, Lian Z. Mechanochemical Synthesis of Aryl Fluorides by Using Ball Milling and a Piezoelectric Material as the Redox Catalyst. Angew Chem Int Ed Engl 2023; 62:e202307054. [PMID: 37523257 DOI: 10.1002/anie.202307054] [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: 05/19/2023] [Revised: 07/27/2023] [Accepted: 07/31/2023] [Indexed: 08/02/2023]
Abstract
Aryl fluorides are important structural motifs in many pharmaceuticals. Although the Balz-Schiemann reaction provides an entry to aryl fluorides from aryldiazonium tetrafluoroborates, it suffers from drawbacks such as long reaction time, high temperature, toxic solvent, toxic gas release, and low functional group tolerance. Here, we describe a general method for the synthesis of aryl fluorides from aryldiazonium tetrafluoroborates using a piezoelectric material as redox catalyst under ball milling conditions in the presence of Selectfluor. This approach effectively addresses the aforementioned limitations. Furthermore, the piezoelectric material can be recycled multiple times. Mechanistic investigations indicate that this fluorination reaction may proceed via a radical pathway, and Selectfluor plays a dual role as both a source of fluorine and a terminal reductant.
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Affiliation(s)
- Xiaohong Wang
- Department of Dermatology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Xuemei Zhang
- Department of Dermatology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Li Xue
- Department of Dermatology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Qingqing Wang
- Department of Dermatology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Fengzhi You
- Department of Dermatology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Lunzhi Dai
- Department of Dermatology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, Chengdu, P. R. China
| | - Jiagang Wu
- Department of Materials Science, Sichuan University, 610064, Chengdu, China
| | - Søren Kramer
- Department of Chemistry, Technical University of Denmark, 2800, Kgs. Lyngby, Denmark
| | - Zhong Lian
- Department of Dermatology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, Chengdu, P. R. China
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19
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Zhang L, Yan J, Ahmadli D, Wang Z, Ritter T. Electron-Transfer-Enabled Concerted Nucleophilic Fluorination of Azaarenes: Selective C-H Fluorination of Quinolines. J Am Chem Soc 2023; 145:20182-20188. [PMID: 37695320 PMCID: PMC10515641 DOI: 10.1021/jacs.3c07119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Indexed: 09/12/2023]
Abstract
Direct C-H fluorination is an efficient strategy to construct aromatic C-F bonds, but the cleavage of specific C-H bonds in the presence of other functional groups and the high barrier of C-F bond formation make the transformation challenging. Progress for the electrophilic fluorination of arenes has been reported, but a similar transformation for electron-deficient azaarenes has remained elusive due to the high energy of the corresponding Wheland intermediates. Nucleophilic fluorination of electron-deficient azaarenes is difficult owing to the identity of the Meisenheimer intermediate after fluoride attack, from which fluoride elimination to regenerate the substrate is favored over hydride elimination to form the product. Herein, we report a new concept for C-H nucleophilic fluorination without the formation of azaarene Meisenheimer intermediates through a chain process with an asynchronous concerted F--e--H+ transfer. The concerted nucleophilic aromatic substitution strategy allows for the first successful nucleophilic oxidative fluorination of quinolines.
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Affiliation(s)
- Li Zhang
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Jiyao Yan
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
- Institute
of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Dilgam Ahmadli
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
- Institute
of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Zikuan Wang
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Tobias Ritter
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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20
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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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21
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Simpson MM, Lam CC, Goodman JM, Balasubramanian S. Selective Functionalisation of 5-Methylcytosine by Organic Photoredox Catalysis. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 135:e202304756. [PMID: 38516645 PMCID: PMC10953388 DOI: 10.1002/ange.202304756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Indexed: 03/23/2024]
Abstract
The epigenetic modification 5-methylcytosine plays a vital role in development, cell specific gene expression and disease states. The selective chemical modification of the 5-methylcytosine methyl group is challenging. Currently, no such chemistry exists. Direct functionalisation of 5-methylcytosine would improve the detection and study of this epigenetic feature. We report a xanthone-photosensitised process that introduces a 4-pyridine modification at a C(sp3)-H bond in the methyl group of 5-methylcytosine. We propose a reaction mechanism for this type of reaction based on density functional calculations and apply transition state analysis to rationalise differences in observed reaction efficiencies between cyanopyridine derivatives. The reaction is initiated by single electron oxidation of 5-methylcytosine followed by deprotonation to generate the methyl group radical. Cross coupling of the methyl radical with 4-cyanopyridine installs a 4-pyridine label at 5-methylcytosine. We demonstrate use of the pyridination reaction to enrich 5-methylcytosine-containing ribonucleic acid.
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Affiliation(s)
- Mathew M. Simpson
- Yusuf Hamied Department of ChemistryUniversity of CambridgeLensfield RoadCB2 1EWCambridgeUK
| | - Ching Ching Lam
- Yusuf Hamied Department of ChemistryUniversity of CambridgeLensfield RoadCB2 1EWCambridgeUK
| | - Jonathan M. Goodman
- Yusuf Hamied Department of ChemistryUniversity of CambridgeLensfield RoadCB2 1EWCambridgeUK
| | - Shankar Balasubramanian
- Yusuf Hamied Department of ChemistryUniversity of CambridgeLensfield RoadCB2 1EWCambridgeUK
- Cancer ResearchUKCambridge Institute Li Ka Shing CentreUniversity of CambridgeRobinson WayCB2 0RECambridgeUK
- School of Clinical MedicineUniversity of CambridgeCB2 0SPCambridgeUK
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22
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Simpson MM, Lam CC, Goodman JM, Balasubramanian S. Selective Functionalisation of 5-Methylcytosine by Organic Photoredox Catalysis. Angew Chem Int Ed Engl 2023; 62:e202304756. [PMID: 37118885 PMCID: PMC10952617 DOI: 10.1002/anie.202304756] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/27/2023] [Accepted: 04/28/2023] [Indexed: 04/30/2023]
Abstract
The epigenetic modification 5-methylcytosine plays a vital role in development, cell specific gene expression and disease states. The selective chemical modification of the 5-methylcytosine methyl group is challenging. Currently, no such chemistry exists. Direct functionalisation of 5-methylcytosine would improve the detection and study of this epigenetic feature. We report a xanthone-photosensitised process that introduces a 4-pyridine modification at a C(sp3 )-H bond in the methyl group of 5-methylcytosine. We propose a reaction mechanism for this type of reaction based on density functional calculations and apply transition state analysis to rationalise differences in observed reaction efficiencies between cyanopyridine derivatives. The reaction is initiated by single electron oxidation of 5-methylcytosine followed by deprotonation to generate the methyl group radical. Cross coupling of the methyl radical with 4-cyanopyridine installs a 4-pyridine label at 5-methylcytosine. We demonstrate use of the pyridination reaction to enrich 5-methylcytosine-containing ribonucleic acid.
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Affiliation(s)
- Mathew M. Simpson
- Yusuf Hamied Department of ChemistryUniversity of CambridgeLensfield RoadCB2 1EWCambridgeUK
| | - Ching Ching Lam
- Yusuf Hamied Department of ChemistryUniversity of CambridgeLensfield RoadCB2 1EWCambridgeUK
| | - Jonathan M. Goodman
- Yusuf Hamied Department of ChemistryUniversity of CambridgeLensfield RoadCB2 1EWCambridgeUK
| | - Shankar Balasubramanian
- Yusuf Hamied Department of ChemistryUniversity of CambridgeLensfield RoadCB2 1EWCambridgeUK
- Cancer ResearchUKCambridge Institute Li Ka Shing CentreUniversity of CambridgeRobinson WayCB2 0RECambridgeUK
- School of Clinical MedicineUniversity of CambridgeCB2 0SPCambridgeUK
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23
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He H, Liu J, Wang T, Guo L, Zhang W, Chen X. Chemo- and regioselectivities of the TBAF-catalyzed C F bond allylation of trifluoromethylalkenes: A theoretical view. MOLECULAR CATALYSIS 2023. [DOI: 10.1016/j.mcat.2023.113111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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24
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Liu M, Liu J, Li J, Zhao Z, Zhou K, Li Y, He P, Wu J, Bao Z, Yang Q, Yang Y, Ren Q, Zhang Z. Blending Aryl Ketone in Covalent Organic Frameworks to Promote Photoinduced Electron Transfer. J Am Chem Soc 2023; 145:9198-9206. [PMID: 37125453 DOI: 10.1021/jacs.3c01273] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Aryl-ketone derivatives have been acknowledged as promising organic photocatalysts for photosynthesis. However, they are limited by their photostability and have been less explored for photoinduced electron transfer (PET) applications. Herein we demonstrate a novel strategy to cover the shortage of aryl-ketone photocatalysts and control the photoreactivity by implanting symmetric aryl ketones into the conjugated covalent organic frameworks (COFs). To prove the concept, three comparative materials with the same topology and varied electronic structures were built, adopting truxenone knot and functionalized terephthalaldehyde linkers. Spectroscopic investigation and excited carrier dynamics analysis disclosed improvements in the photostability and electronic transfer efficiency as well as the structure-performance relationships toward N-aryl tetrahydroisoquinoline oxidation. This system provides a robust rule of thumb for designing new-generation aryl-ketone photocatalysts.
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Affiliation(s)
- Mingjie Liu
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Junnan Liu
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Jing Li
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Zhenghua Zhao
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Kai Zhou
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Yueming Li
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Peipei He
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Jiashu Wu
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Zongbi Bao
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Qiwei Yang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Yiwen Yang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Qilong Ren
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Zhiguo Zhang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
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25
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Sun Q, Li H, Chen X, Hao J, Deng H, Jiang H. Silver-Promoted Radical Cascade Aryldifluoromethylation/Cyclization of 2-Allyloxybenzaldehydes for the Synthesis of 3-Aryldifluoromethyl-Containing Chroman-4-one Derivatives. Molecules 2023; 28:molecules28083578. [PMID: 37110812 PMCID: PMC10142801 DOI: 10.3390/molecules28083578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/12/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
A convenient silver-promoted radical cascade aryldifluoromethylation/cyclization of 2-allyloxybenzaldehydes has been developed. Experimental studies disclosed that the addition of aryldifluoromethyl radicals in situ produced from easily accessible gem-difluoroarylacetic acids to unactivated double bonds in 2-allyloxybenzaldehyde was an effective route to access a series of 3-aryldifluoromethyl-containing chroman-4-one derivatives in moderate to good yields under mild reaction conditions.
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Affiliation(s)
- Qianqian Sun
- Department of Chemistry, Shanghai University, Shanghai 200444, China
| | - Hongxiao Li
- Department of Chemistry, Shanghai University, Shanghai 200444, China
| | - Xingyu Chen
- Department of Chemistry, Shanghai University, Shanghai 200444, China
| | - Jian Hao
- Department of Chemistry, Shanghai University, Shanghai 200444, China
| | - Hongmei Deng
- Laboratory for Microstructures, Shanghai University, Shanghai 200444, China
| | - Haizhen Jiang
- Department of Chemistry, Shanghai University, Shanghai 200444, China
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
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26
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Xu M, Ou J, Luo K, Liang R, Liu J, Li N, Hu B, Liu K. External Catalyst- and Additive-Free Photo-Oxidation of Aromatic Alcohols to Carboxylic Acids or Ketones Using Air/O2. Molecules 2023; 28:molecules28073031. [PMID: 37049794 PMCID: PMC10096038 DOI: 10.3390/molecules28073031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 03/31/2023] Open
Abstract
We present an environment-friendly and highly efficient method for the oxidation of aromatic alcohols to carboxylic acids or ketones in air via light irradiation under external catalyst-, additive-, and base-free conditions. The photoreaction system exhibits a wide substrate scope and the potential for large-scale applications. Most of the desired products are easily obtained via recrystallization and separation from low-boiling reaction medium acetone in good yields, and the products can be subsequent directly transformed without further purification.
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Affiliation(s)
- Meng Xu
- School of Materials Science and Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Jinhua Ou
- School of Materials Science and Engineering, Hunan Institute of Technology, Hengyang 421002, China
- Correspondence: (J.O.); (K.L.)
| | - Kejun Luo
- Analytical Testing Center, Changsha Research Institute of Mining and Metallurgy Co., Ltd., Changsha 410012, China
| | - Rongtao Liang
- School of Materials Science and Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Jian Liu
- School of Materials Science and Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Ni Li
- School of Materials Science and Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Bonian Hu
- School of Materials Science and Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Kaijian Liu
- School of Materials Science and Engineering, Hunan Institute of Technology, Hengyang 421002, China
- Correspondence: (J.O.); (K.L.)
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27
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Bo C, Chen F, Bu Q, Du ZH, Li M, Dai B, Liu N. Visible-Light-Driven Organocatalytic Alkoxylation of Benzylic C-H Bonds. J Org Chem 2023; 88:3532-3538. [PMID: 36881000 DOI: 10.1021/acs.joc.2c02743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
A variety of strategies for direct alkoxylation of the benzyl C-H bond have been developed toward the construction of benzyl ethers. The light-induced benzyl C-H bond alkoxylation provides an alternative strategy for the synthesis of these important intermediates. The photocatalyzed alkoxylation of the benzyl C-H bond has dominated by metal-catalyzed methods. Herein, we reported a light-driven organocatalytic approach for alkoxylation of the benzyl C-H bond by the use of 9,10-dibromoanthracene as a photocatalyst and employing N-fluorobenzenesulfonimide as an oxidant. This reaction proceeds at room temperature and is capable of converting a variety of alkyl biphenyl and coupling partners, including a variety of alcohol and carboxylic acid, as well as peroxide, to the desired products under 400 nm light irradiation.
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Affiliation(s)
- Chunbo Bo
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang 832003, China
| | - Fei Chen
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang 832003, China
| | - Qingqing Bu
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang 832003, China
| | - Zhi-Hong Du
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang 832003, China
| | - Min Li
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang 832003, China
| | - Bin Dai
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang 832003, China
| | - Ning Liu
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang 832003, China
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28
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Roy S, Panja S, Sahoo SR, Chatterjee S, Maiti D. Enroute sustainability: metal free C-H bond functionalisation. Chem Soc Rev 2023; 52:2391-2479. [PMID: 36924227 DOI: 10.1039/d0cs01466d] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
The term "C-H functionalisation" incorporates C-H activation followed by its transformation. In a single line, this can be defined as the conversion of carbon-hydrogen bonds into carbon-carbon or carbon-heteroatom bonds. The catalytic functionalisation of C-H bonds using transition metals has emerged as an atom-economical technique to engender new bonds without activated precursors which can be considered as a major drawback while attempting large-scale synthesis. Replacing the transition-metal-catalysed approach with a metal-free strategy significantly offers an alternative route that is not only inexpensive but also environmentally benign to functionalize C-H bonds. Recently metal free synthetic approaches have been flourishing to functionalize C-H bonds, motivated by the search for greener, cost-effective, and non-toxic catalysts. In this review, we will highlight the comprehensive and up-to-date discussion on recent examples of ground-breaking research on green and sustainable metal-free C-H bond functionalisation.
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Affiliation(s)
- Sayan Roy
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Subir Panja
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Sumeet Ranjan Sahoo
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Sagnik Chatterjee
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Debabrata Maiti
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India. .,Department of Interdisciplinary Program in Climate Studies, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
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29
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Shigeno M, Kajima A, Toyama E, Korenaga T, Yamakoshi H, Nozawa-Kumada K, Kondo Y. LiHMDS-Mediated Deprotonative Coupling of Toluenes with Ketones. Chemistry 2023; 29:e202203549. [PMID: 36479733 DOI: 10.1002/chem.202203549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/05/2022] [Accepted: 12/06/2022] [Indexed: 12/12/2022]
Abstract
We demonstrate that lithium hexamethyldisilazide (LiHMDS) acts as an effective base for deprotonative coupling reactions of toluenes with ketones to afford stilbenes. Various functionalities (halogen, OCF3 , amide, Me, aryl, alkenyl, alkynyl, SMe, and SPh) are allowed on the toluenes. Notably, this system proved successful with low-reactive toluenes bearing a large pKa value compared to that of the conjugate acid of LiHMDS (hexamethyldisilazane, 25.8, THF), as demonstrated by 4-phenyltoluene (38.57, THF) and toluene itself (∼43, DMSO).
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Affiliation(s)
- Masanori Shigeno
- Department of Biophysical Chemistry Graduate School of Pharmaceutical Science, Tohoku University, 6-3 Aoba, Sendai, 980-8578, Japan.,JST, PRESTO, Kawaguchi, Saitama, 332-0012, Japan
| | - Akihisa Kajima
- Department of Biophysical Chemistry Graduate School of Pharmaceutical Science, Tohoku University, 6-3 Aoba, Sendai, 980-8578, Japan
| | - Eito Toyama
- Department of Biophysical Chemistry Graduate School of Pharmaceutical Science, Tohoku University, 6-3 Aoba, Sendai, 980-8578, Japan
| | - Toshinobu Korenaga
- Department of Chemistry and Biological Sciences Faculty of Science and Engineering, Iwate University Ueda, Morioka, 020-8551, Japan.,Soft-Path Science and Engineering Research Center (SPERC), Iwate University, Ueda, Morioka, 020-8551, Japan
| | - Hiroyuki Yamakoshi
- Central Analytical Center, Graduate School of Pharmaceutical Science, Tohoku University, 6-3 Aoba, Sendai, 980-8578, Japan
| | - Kanako Nozawa-Kumada
- Department of Biophysical Chemistry Graduate School of Pharmaceutical Science, Tohoku University, 6-3 Aoba, Sendai, 980-8578, Japan
| | - Yoshinori Kondo
- Department of Biophysical Chemistry Graduate School of Pharmaceutical Science, Tohoku University, 6-3 Aoba, Sendai, 980-8578, Japan
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30
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Fan X, Zhang M, Gao Y, Zhou Q, Zhang Y, Yu J, Xu W, Yan J, Liu H, Lei Z, Ter YC, Chanmungkalakul S, Lum Y, Liu X, Cui G, Wu J. Stepwise on-demand functionalization of multihydrosilanes enabled by a hydrogen-atom-transfer photocatalyst based on eosin Y. Nat Chem 2023; 15:666-676. [PMID: 36894703 DOI: 10.1038/s41557-023-01155-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 02/03/2023] [Indexed: 03/11/2023]
Abstract
Organosilanes are of vital importance for modern human society, having found widespread applications in functional materials, organic synthesis, drug discovery and life sciences. However, their preparation remains far from trivial, and on-demand synthesis of heteroleptic substituted silicon reagents is a formidable challenge. The generation of silyl radicals from hydrosilanes via direct hydrogen-atom-transfer (HAT) photocatalysis represents the most atom-, step-, redox- and catalyst-economic pathway for the activation of hydrosilanes. Here, in view of the green characteristics of neutral eosin Y (such as its abundance, low cost, metal-free nature, absorption of visible light and excellent selectivity), we show that using it as a direct HAT photocatalyst enables the stepwise custom functionalization of multihydrosilanes, giving access to fully substituted silicon compounds. By exploiting this strategy, we realize preferable hydrogen abstraction of Si-H bonds in the presence of active C-H bonds, diverse functionalization of hydrosilanes (for example, alkylation, vinylation, allylation, arylation, deuteration, oxidation and halogenation), and remarkably selective monofunctionalization of di- and trihydrosilanes.
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Affiliation(s)
- Xuanzi Fan
- Department of Chemistry, National University of Singapore, Singapore, Republic of Singapore
| | - Muliang Zhang
- Department of Chemistry, National University of Singapore, Singapore, Republic of Singapore
| | - Yuanjun Gao
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
| | - Qi Zhou
- Department of Chemistry, National University of Singapore, Singapore, Republic of Singapore
| | - Yanbin Zhang
- Department of Chemistry, National University of Singapore, Singapore, Republic of Singapore
| | - Jiajia Yu
- Department of Chemistry, National University of Singapore, Singapore, Republic of Singapore
| | - Wengang Xu
- Department of Chemistry, National University of Singapore, Singapore, Republic of Singapore
| | - Jianming Yan
- Department of Chemistry, National University of Singapore, Singapore, Republic of Singapore
| | - Haiwang Liu
- Department of Chemistry, National University of Singapore, Singapore, Republic of Singapore
| | - Zhexuan Lei
- Department of Chemistry, National University of Singapore, Singapore, Republic of Singapore
| | - Yan Chong Ter
- Department of Chemistry, National University of Singapore, Singapore, Republic of Singapore
| | - Supphachok Chanmungkalakul
- Fluorescence Research Group, Singapore University of Technology and Design, Singapore, Republic of Singapore
| | - Yanwei Lum
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Republic of Singapore
| | - Xiaogang Liu
- Fluorescence Research Group, Singapore University of Technology and Design, Singapore, Republic of Singapore
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
| | - Jie Wu
- Department of Chemistry, National University of Singapore, Singapore, Republic of Singapore.
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31
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Ghosh S, Qu ZW, Roy S, Grimme S, Chatterjee I. Photoredox Catalyzed Single C-F Bond Activation of Trifluoromethyl Ketones: A Solvent Controlled Divergent Access of gem-Difluoromethylene Containing Scaffolds. Chemistry 2023; 29:e202203428. [PMID: 36445786 DOI: 10.1002/chem.202203428] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 11/30/2022]
Abstract
Selective defluorinative functionalization of trifluoromethyl ketones is a long-standing challenge owing to the exhaustive mode of the process. To meet the demands for the installation of the gem-difluoromethylene unit for the construction of the molecular architectures of well-known pharmaceuticals and agrochemicals, a distinct pathway is thereby highly desirable. Here, a protocol is introduced that allows the divergent synthesis of gem-difluoromethylene group containing tetrahydrofuran derivatives and linear ketones via single C-F bond activation of trifluoromethyl ketones using visible-light photoredox catalysis in the presence of suitable olefins as trapping partner. The choice of appropriate solvent and catalyst plays a significant role in controlling the divergent behavior of this protocol. Highly reducing photo-excited catalysts are found to be responsible for the generation of α,α-difluoromethyl ketone (DFMK) radicals as the key intermediate via a SET process. This protocol also results in a high diastereoselectivity towards the formation of partially fluorinated cyclic ketal derivatives with simultaneous construction of one C-C and two C-O bonds. State-of-the-art DFT calculations are performed to address the origin of diastereoselectivity as well as the divergence of this protocol.
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Affiliation(s)
- Soumen Ghosh
- Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab, 140001, India
| | - Zheng-Wang Qu
- Mulliken Center for Theoretical Chemistry, Clausius Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstrasse 4, 53115, Bonn, Germany
| | - Sourav Roy
- Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab, 140001, India
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, Clausius Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstrasse 4, 53115, Bonn, Germany
| | - Indranil Chatterjee
- Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab, 140001, India
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32
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Tian Y, Zheng L, Wang Z, Li Z, Fu W. Metal-Free Electrochemical Oxidative Difluoroethylation/Cyclization of Olefinic Amides To Construct Difluoroethylated Azaheterocycles. J Org Chem 2023; 88:1875-1883. [PMID: 36669162 DOI: 10.1021/acs.joc.2c02579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A new strategy of electrochemical oxidative difluoroethylation to generate difluoroethyl radical with sodium difluoroethylsulfinate (DFES-Na) has been reported for the first time. The method allows quick access to a variety of valuable difluoroethylated azaheterocycles including oxindoles and isoquinoline-1,3-diones via radical tandem difluoroethylation/cyclization in moderate to good yields. The electrochemical cyclopropyldifluoromethylation of N-arylacrylamides also works well using this strategy. Moreover, radical capture and cyclic voltammetry (CV) experiments are also carried out to determine the proposed mechanism.
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Affiliation(s)
- Yunfei Tian
- College of Chemistry and Chemical Engineering, Key Laboratory of Fuction-Oriented Porous Materials of Henan Province, Luoyang Normal University, Luoyang, Henan 471934, P. R. China
| | - Luping Zheng
- College of Chemistry and Chemical Engineering, Key Laboratory of Fuction-Oriented Porous Materials of Henan Province, Luoyang Normal University, Luoyang, Henan 471934, P. R. China
| | - Zhiqiang Wang
- College of Chemistry and Chemical Engineering, Key Laboratory of Fuction-Oriented Porous Materials of Henan Province, Luoyang Normal University, Luoyang, Henan 471934, P. R. China
| | - Zejiang Li
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Hebei University, Baoding, Hebei 071002, P. R. China
| | - Weijun Fu
- College of Chemistry and Chemical Engineering, Key Laboratory of Fuction-Oriented Porous Materials of Henan Province, Luoyang Normal University, Luoyang, Henan 471934, P. R. China
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33
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Zhu JL, Schull CR, Tam AT, Rentería-Gómez Á, Gogoi AR, Gutierrez O, Scheidt KA. Photoinduced Acylations Via Azolium-Promoted Intermolecular Hydrogen Atom Transfer. J Am Chem Soc 2023; 145:1535-1541. [PMID: 36625715 DOI: 10.1021/jacs.2c12845] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Photoinduced hydrogen atom transfer (HAT) has been developed as a powerful tool to generate synthetically valuable radical species. The direct photoexcitation of ketones has been known to promote HAT or to generate acyl radicals through Norrish-type pathways, but these modalities remain severely limited by radical side reactions. We report herein a catalyst- and transition metal-free method for the acylation of C-H bonds that leverages the unique properties of stable, isolable acyl azolium species. Specifically, acyl azolium salts are shown to undergo an intermolecular and regioselective HAT upon LED irradiation with a range of substrates bearing active C-H bonds followed by C-C bond formation to afford ketones. Experimental and computational studies support photoexcitation of the acyl azolium followed by facile intersystem crossing to access triplet diradical species that promote selective HAT and radical-radical cross-coupling.
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Affiliation(s)
- Joshua L Zhu
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois60208, United States
| | - Cullen R Schull
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois60208, United States
| | - Anthony T Tam
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois60208, United States
| | - Ángel Rentería-Gómez
- Department of Chemistry, Texas A&M University, College Station, Texas77843, United States
| | - Achyut Ranjan Gogoi
- Department of Chemistry, Texas A&M University, College Station, Texas77843, United States
| | - Osvaldo Gutierrez
- Department of Chemistry, Texas A&M University, College Station, Texas77843, United States
| | - Karl A Scheidt
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois60208, United States
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34
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Abstract
The emergence of modern photocatalysis, characterized by mildness and selectivity, has significantly spurred innovative late-stage C-H functionalization approaches that make use of low energy photons as a controllable energy source. Compared to traditional late-stage functionalization strategies, photocatalysis paves the way toward complementary and/or previously unattainable regio- and chemoselectivities. Merging the compelling benefits of photocatalysis with the late-stage functionalization workflow offers a potentially unmatched arsenal to tackle drug development campaigns and beyond. This Review highlights the photocatalytic late-stage C-H functionalization strategies of small-molecule drugs, agrochemicals, and natural products, classified according to the targeted C-H bond and the newly formed one. Emphasis is devoted to identifying, describing, and comparing the main mechanistic scenarios. The Review draws a critical comparison between established ionic chemistry and photocatalyzed radical-based manifolds. The Review aims to establish the current state-of-the-art and illustrate the key unsolved challenges to be addressed in the future. The authors aim to introduce the general readership to the main approaches toward photocatalytic late-stage C-H functionalization, and specialist practitioners to the critical evaluation of the current methodologies, potential for improvement, and future uncharted directions.
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Affiliation(s)
- Peter Bellotti
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149Münster, Germany
| | - Huan-Ming Huang
- School of Physical Science and Technology, ShanghaiTech University, 201210Shanghai, China
| | - Teresa Faber
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149Münster, Germany
| | - Frank Glorius
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149Münster, Germany
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35
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Hintz H, Bower J, Tang J, LaLama M, Sevov C, Zhang S. Copper-Catalyzed Electrochemical C-H Fluorination. CHEM CATALYSIS 2023; 3:100491. [PMID: 36743279 PMCID: PMC9894310 DOI: 10.1016/j.checat.2022.100491] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We report the systematic development of an electrooxidative methodology that translates stoichiometric C-H fluorination reactivity of an isolable CuIII fluoride complex into a catalytic process. The critical challenges of electrocatalysis with a highly reactive CuIII species were addressed by the judicious selection of electrolyte, F- source, and sacrificial electron acceptor. Catalyst-controlled C-H fluorination occurs with a preference for hydridic C-H bonds with high bond dissociation energies over weaker but less hydridic C-H bonds. The selectivity is driven by an oxidative asynchronous proton-coupled elelctron transfer (PCET) at an electrophilic CuIII-F complex. We further demonstrate that the asynchronicity factor of hydrogen atom transfer η can be used as a guideline to rationalize the selectivity of C-H fluorination.
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Affiliation(s)
- Heather Hintz
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Jamey Bower
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Jinghua Tang
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Matthew LaLama
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Christo Sevov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
| | - Shiyu Zhang
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, United States
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36
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Wang M, Ren J, Xiao Q, Song A, Yu S, Wang R, Xing L. Photocatalytic One-Pot Synthesis of Quinazolinone Under Ambient Conditions. Catal Letters 2023. [DOI: 10.1007/s10562-022-04266-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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37
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Wang XW, Li RX, Deng Y, Fu MQH, Zhao YN, Guan Z, He YH. Direct Hydroxylarylation of Benzylic Carbons (sp 3/sp 2/sp) via Radical-Radical Cross-Coupling Powered by Paired Electrolysis. J Org Chem 2023; 88:329-340. [PMID: 36563045 DOI: 10.1021/acs.joc.2c02363] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Diaryl alcohol moieties are widespread in pharmaceuticals. Existing methods for the synthesis of diaryl alcohols require the use of pre-functionalized benzylic alcohols, aromatic aldehydes, or ketones as starting materials. Herein, the first convergent paired electrochemical approach to the direct hydroxylarylation of unactivated benzylic carbons (sp3/sp2/sp) is proposed. This protocol features direct functionalization of unactivated benzylic C(sp3)-H bonds and benzylic sp2/sp-carbons, mild conditions (open air, room temperature), an environmentally friendly procedure (without any external catalyst/mediator/additive), and direct access to sterically hindered alcohols from inexpensive and readily available alkyl/alkenyl/alkynylbenzenes. Mechanistic studies, including divided-cell experiments, isotope labeling, radical trapping, electron paramagnetic resonance, reaction kinetics, and cyclic voltammetry, strongly support the proposed radical-radical cross-coupling between transient ketyl radicals and persistent radical anions. Gram-scale synthesis and diversification of drug derivatives have visualized the tremendous potential of this protocol for practical applications.
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Affiliation(s)
- Xiao-Wen Wang
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
| | - Rui-Xue Li
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
| | - Yang Deng
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
| | - Ming-Qiu-Hao Fu
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
| | - Ya-Nan Zhao
- Analytical and Testing Center, Southwest University, Chongqing 400715, China
| | - Zhi Guan
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
| | - Yan-Hong He
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
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38
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Yakubov S, Stockerl WJ, Tian X, Shahin A, Mandigma MJP, Gschwind RM, Barham JP. Benzoates as photosensitization catalysts and auxiliaries in efficient, practical, light-powered direct C(sp 3)-H fluorinations. Chem Sci 2022; 13:14041-14051. [PMID: 36540818 PMCID: PMC9728569 DOI: 10.1039/d2sc05735b] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 10/28/2022] [Indexed: 12/14/2023] Open
Abstract
Of the methods for direct fluorination of unactivated C(sp3)-H bonds, photosensitization of SelectFluor is a promising approach. Although many substrates can be activated with photosensitizing catalysts, issues remain that hamper fluorination of complex molecules. Alcohol- or amine-containing functional groups are not tolerated, fluorination regioselectivity follows factors endogenous to the substrate and cannot be influenced by the catalyst, and reactions are highly air-sensitive. We report that benzoyl groups serve as highly efficient photosensitizers which, in combination with SelectFluor, enable visible light-powered direct fluorination of unactivated C(sp3)-H bonds. Compared to previous photosensitizer architectures, the benzoyls have versatility to function both (i) as a photosensitizing catalyst for simple substrate fluorinations and (ii) as photosensitizing auxiliaries for complex molecule fluorinations that are easily installed and removed without compromising yield. Our auxiliary approach (i) substantially decreases the reaction's induction period, (ii) enables C(sp3)-H fluorination of many substrates that fail under catalytic conditions, (iii) increases kinetic reproducibility, and (iv) promotes reactions to higher yields, in shorter times, on multigram scales, and even under air. Observations and mechanistic studies suggest an intimate 'assembly' of auxiliary and SelectFluor prior/after photoexcitation. The auxiliary allows other EnT photochemistry under air. Examples show how auxiliary placement proximally directs regioselectivity, where previous methods are substrate-directed.
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Affiliation(s)
- Shahboz Yakubov
- Fakultät für Chemie und Pharmazie, Universität Regensburg 93040 Regensburg Germany
| | - Willibald J Stockerl
- Fakultät für Chemie und Pharmazie, Universität Regensburg 93040 Regensburg Germany
| | - Xianhai Tian
- Fakultät für Chemie und Pharmazie, Universität Regensburg 93040 Regensburg Germany
| | - Ahmed Shahin
- Fakultät für Chemie und Pharmazie, Universität Regensburg 93040 Regensburg Germany
- Chemistry Department, Faculty of Science, Benha University 13518 Benha Egypt
| | - Mark John P Mandigma
- Fakultät für Chemie und Pharmazie, Universität Regensburg 93040 Regensburg Germany
| | - Ruth M Gschwind
- Fakultät für Chemie und Pharmazie, Universität Regensburg 93040 Regensburg Germany
| | - Joshua P Barham
- Fakultät für Chemie und Pharmazie, Universität Regensburg 93040 Regensburg Germany
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39
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Selective functionalization of benzylic C(sp3)–H bonds to synthesize complex molecules. Chem 2022. [DOI: 10.1016/j.chempr.2022.10.005] [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]
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40
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Stangier M, Scheremetjew A, Ackermann L. Chemo- and Site-Selective Electro-Oxidative Alkane Fluorination by C(sp 3 )-H Cleavage. Chemistry 2022; 28:e202201654. [PMID: 35844078 PMCID: PMC9804291 DOI: 10.1002/chem.202201654] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Indexed: 01/05/2023]
Abstract
Electrochemical fluorinations of C(sp3 )-H bonds with a nucleophilic fluoride source have been accomplished in a chemo- and site-selective fashion, avoiding the use of electrophilic F+ sources and stoichiometric oxidants. The introduced metal-free strategy exhibits high functional group tolerance, setting the stage for late-stage fluorinations of biorelevant motifs. The synthetic utility of the C(sp3 )-H fluorination was reflected by subsequent one-pot arylation of the generated benzylic fluorides.
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Affiliation(s)
- Maximilian Stangier
- Institut für Organische und Biomolekulare Chemie Wöhler Research Institute for Sustainable Chemistry (WISCh)Georg-August-Universität GöttingenTammannstrasse 237077GöttingenGermany
| | - Alexej Scheremetjew
- Institut für Organische und Biomolekulare Chemie Wöhler Research Institute for Sustainable Chemistry (WISCh)Georg-August-Universität GöttingenTammannstrasse 237077GöttingenGermany
| | - Lutz Ackermann
- Institut für Organische und Biomolekulare Chemie Wöhler Research Institute for Sustainable Chemistry (WISCh)Georg-August-Universität GöttingenTammannstrasse 237077GöttingenGermany
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41
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Dey J, Paul S, Bhakat M, Guin J. Photocatalytic Incorporation of an Oxime Ether Functional Group at Inert C(sp 3)–H Bonds via HAT. Org Lett 2022; 24:8047-8051. [DOI: 10.1021/acs.orglett.2c03300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jayanta Dey
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A and 2B Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal 700032, India
| | - Subhasis Paul
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A and 2B Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal 700032, India
| | - Manotosh Bhakat
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A and 2B Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal 700032, India
| | - Joyram Guin
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A and 2B Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal 700032, India
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42
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Zhang Y, Sahoo PK, Ren P, Qin Y, Cauwenbergh R, Nimmegeers P, SivaRaman G, Van Passel S, Guidetti A, Das S. Transition metal-free approach for late-stage benzylic C(sp 3)-H etherifications and esterifications. Chem Commun (Camb) 2022; 58:11454-11457. [PMID: 36148867 DOI: 10.1039/d2cc02661a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a transition metal-free approach for the regioselective functionalization of benzylic C(sp3)-H bonds using alcohols and carboxylic acids as the nucleophiles. This straightforward and general route has provided various benzylic ethers and esters, including twelve pharmaceutically relevant compounds.
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Affiliation(s)
- Yu Zhang
- ORSY Division, Department of Chemistry, Universiteit Antwerpen, Campus Groenenborger, Groenenborgerlaan 171, 2020 Antwerpen, Belgium.
| | - Prakash Kumar Sahoo
- ORSY Division, Department of Chemistry, Universiteit Antwerpen, Campus Groenenborger, Groenenborgerlaan 171, 2020 Antwerpen, Belgium.
| | - Peng Ren
- ORSY Division, Department of Chemistry, Universiteit Antwerpen, Campus Groenenborger, Groenenborgerlaan 171, 2020 Antwerpen, Belgium.
| | - Yuman Qin
- ORSY Division, Department of Chemistry, Universiteit Antwerpen, Campus Groenenborger, Groenenborgerlaan 171, 2020 Antwerpen, Belgium.
| | - Robin Cauwenbergh
- ORSY Division, Department of Chemistry, Universiteit Antwerpen, Campus Groenenborger, Groenenborgerlaan 171, 2020 Antwerpen, Belgium.
| | - Philippe Nimmegeers
- Department of Engineering Management, Universiteit Antwerpen, Prinsstraat 13, 2000, Antwerpen, Belgium.,Intelligence in Processes, Advanced Catalysts and Solvents (iPRACS), Faculty of Applied Engineering, Universiteit Antwerpen, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
| | - Gandhi SivaRaman
- Department of Chemistry, Gandhigram Rural Institute, Gandhigram, 624032, Tamilnadu, India
| | - Steven Van Passel
- Department of Engineering Management, Universiteit Antwerpen, Prinsstraat 13, 2000, Antwerpen, Belgium.,Nanolab Centre of Excellence, Prinsstraat 13, 2000, Antwerpen, Belgium
| | - Andrea Guidetti
- Biophysics and Biomedical Physics (BIMEF), Department of Chemistry, University of Antwerp, B2610 Antwerp, Belgium
| | - Shoubhik Das
- ORSY Division, Department of Chemistry, Universiteit Antwerpen, Campus Groenenborger, Groenenborgerlaan 171, 2020 Antwerpen, Belgium.
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43
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Joshi A, Iqbal Z, Kandwal P, De SR. Pd(II)–Catalyzed Non–Directed Benzylic C(sp3)–H Activation: Cascade C(sp3)–S Bond Cleavage to Access Benzaldehydes from Benzylphenyl Sulfides and Sulfoxides. ASIAN J ORG CHEM 2022. [DOI: 10.1002/ajoc.202200400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Asha Joshi
- NIT Uttarakhand: National Institute of Technology Uttarakhand Department of Chemistry Srinagar INDIA
| | - Zafar Iqbal
- NIT Uttarakhand: National Institute of Technology Uttarakhand Department of Chemistry Srinagar INDIA
| | - Pankaj Kandwal
- NIT Uttarakhand: National Institute of Technology Uttarakhand Department of Chemistry Srinagar INDIA
| | - Saroj Ranjan De
- National Institute of Technology Uttarakhand Dept. of Chemistry Srinagar Garhwal 246174 Srinagar INDIA
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44
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Steiner A, Nelson RC, Dallinger D, Kappe CO. Synthesis of Thiomorpholine via a Telescoped Photochemical Thiol–Ene/Cyclization Sequence in Continuous Flow. Org Process Res Dev 2022; 26:2532-2539. [PMID: 36032361 PMCID: PMC9396661 DOI: 10.1021/acs.oprd.2c00214] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Alexander Steiner
- Institute of Chemistry, University of Graz, NAWI Graz, Heinrichstrasse 28, 8010 Graz, Austria
- Center for Continuous Flow Synthesis and Processing (CCFLOW), Research Center Pharmaceutical Engineering GmbH (RCPE), Inffeldgasse 13, 8010 Graz, Austria
| | - Ryan C. Nelson
- Medicines for All Institute, Virginia Commonwealth University, 737 North Fifth Street, P.O. Box 980100, Richmond, Virginia 23298, United States
| | - Doris Dallinger
- Institute of Chemistry, University of Graz, NAWI Graz, Heinrichstrasse 28, 8010 Graz, Austria
- Center for Continuous Flow Synthesis and Processing (CCFLOW), Research Center Pharmaceutical Engineering GmbH (RCPE), Inffeldgasse 13, 8010 Graz, Austria
| | - C. Oliver Kappe
- Institute of Chemistry, University of Graz, NAWI Graz, Heinrichstrasse 28, 8010 Graz, Austria
- Center for Continuous Flow Synthesis and Processing (CCFLOW), Research Center Pharmaceutical Engineering GmbH (RCPE), Inffeldgasse 13, 8010 Graz, Austria
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45
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Madani A, Anghileri L, Heydenreich M, Möller HM, Pieber B. Benzylic Fluorination Induced by a Charge-Transfer Complex with a Solvent-Dependent Selectivity Switch. Org Lett 2022; 24:5376-5380. [PMID: 35848228 PMCID: PMC9344467 DOI: 10.1021/acs.orglett.2c02050] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
![]()
We present a divergent strategy for the fluorination
of phenylacetic
acid derivatives that is induced by a charge-transfer complex between
Selectfluor and 4-(dimethylamino)pyridine. A comprehensive investigation
of the conditions revealed a critical role of the solvent on the reaction
outcome. In the presence of water, decarboxylative fluorination through
a single-electron oxidation is dominant. Non-aqueous conditions result
in the clean formation of α-fluoro-α-arylcarboxylic acids.
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Affiliation(s)
- Amiera Madani
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany.,Department of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany
| | - Lucia Anghileri
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany.,Department of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany
| | - Matthias Heydenreich
- Institute of Chemistry/Analytical Chemistry, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
| | - Heiko M Möller
- Institute of Chemistry/Analytical Chemistry, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
| | - Bartholomäus Pieber
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
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46
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Li T, Vijeta A, Casadevall C, Gentleman AS, Euser T, Reisner E. Bridging Plastic Recycling and Organic Catalysis: Photocatalytic Deconstruction of Polystyrene via a C–H Oxidation Pathway. ACS Catal 2022; 12:8155-8163. [PMID: 35874621 PMCID: PMC9295126 DOI: 10.1021/acscatal.2c02292] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Chemical recycling
of synthetic polymers represents a promising
strategy to deconstruct plastic waste and make valuable products.
Inspired by small-molecule C–H bond activation, a visible-light-driven
reaction is developed to deconstruct polystyrene (PS) into ∼40%
benzoic acid as well as ∼20% other monomeric aromatic products
at 50 °C and ambient pressure. The practicality of this strategy
is demonstrated by deconstruction of real-world PS foam on a gram
scale. The reaction is proposed to proceed via a C–H bond oxidation
pathway, which is supported by theoretical calculations and experimental
results. Fluorescence quenching experiments also support efficient
electron transfer between the photocatalyst and the polymer substrate,
providing further evidence for the proposed mechanism. This study
introduces concepts from small-molecule catalysis to polymer deconstruction
and provides a promising method to tackle the global crisis of plastic
pollution.
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Affiliation(s)
- Tengfei Li
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
- Department of Natural Sciences, Manchester Metropolitan University, Manchester M1 5GD, U.K
| | - Arjun Vijeta
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
| | - Carla Casadevall
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
| | | | - Tijmen Euser
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K
| | - Erwin Reisner
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
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47
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Huang CY, Li J, Li CJ. Photocatalytic C(sp 3) radical generation via C-H, C-C, and C-X bond cleavage. Chem Sci 2022; 13:5465-5504. [PMID: 35694342 PMCID: PMC9116372 DOI: 10.1039/d2sc00202g] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 04/17/2022] [Indexed: 12/12/2022] Open
Abstract
C(sp3) radicals (R˙) are of broad research interest and synthetic utility. This review collects some of the most recent advancements in photocatalytic R˙ generation and highlights representative examples in this field. Based on the key bond cleavages that generate R˙, these contributions are divided into C–H, C–C, and C–X bond cleavages. A general mechanistic scenario and key R˙-forming steps are presented and discussed in each section. C(sp3) radicals (R˙) are of broad research interest and synthetic utility.![]()
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Affiliation(s)
- Chia-Yu Huang
- Department of Chemistry, FRQNT Centre for Green Chemistry and Catalysis, McGill University 801 Sherbrooke Street W. Montreal Quebec H3A 0B8 Canada
| | - Jianbin Li
- Department of Chemistry, FRQNT Centre for Green Chemistry and Catalysis, McGill University 801 Sherbrooke Street W. Montreal Quebec H3A 0B8 Canada
| | - Chao-Jun Li
- Department of Chemistry, FRQNT Centre for Green Chemistry and Catalysis, McGill University 801 Sherbrooke Street W. Montreal Quebec H3A 0B8 Canada
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48
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Golden DL, Suh SE, Stahl SS. Radical C(sp3)–H functionalization and cross-coupling reactions. Nat Rev Chem 2022; 6:405-427. [DOI: 10.1038/s41570-022-00388-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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49
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Wang J, Huang H, Gao H, Qin G, Xiao T, Jiang Y. DBU/AgOTf Relay‐Catalysis Enabled One‐Pot Synthesis of 1,3‐Dihydroisobenzofurans and Its Conversion to Indanones. Adv Synth Catal 2022. [DOI: 10.1002/adsc.202200287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jiazhuang Wang
- Faculty of Science Kunming University of Science and Technology Kunming 650500 People's Republic of China
| | - Hongtai Huang
- Faculty of Science Kunming University of Science and Technology Kunming 650500 People's Republic of China
| | - Haotian Gao
- Faculty of Science Kunming University of Science and Technology Kunming 650500 People's Republic of China
| | - Guiping Qin
- Faculty of Science Kunming University of Science and Technology Kunming 650500 People's Republic of China
| | - Tiebo Xiao
- Faculty of Science Kunming University of Science and Technology Kunming 650500 People's Republic of China
| | - Yubo Jiang
- Faculty of Science Kunming University of Science and Technology Kunming 650500 People's Republic of China
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50
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Zhao L, Du Z, Ji G, Wang Y, Cai W, He C, Duan C. Eosin Y-Containing Metal-Organic Framework as a Heterogeneous Catalyst for Direct Photoactivation of Inert C-H Bonds. Inorg Chem 2022; 61:7256-7265. [PMID: 35507831 DOI: 10.1021/acs.inorgchem.1c03813] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Xanthene dyes as a class of ideal organic homogeneous photocatalyst have received significant attention in C-H bond activation; however, the inherent nature of fast carrier recombination/deactivation and low stability limits their practical applications. Herein, by the ingenious decoration of eosin Y into a porous metal-organic framework (MOF), a high-performance heterogeneous MOF-based photocatalyst was prepared to efficiently activate inert C-H bonds on the reactants via the hydrogen atom transfer pathway for the functionalization of the C-H bonds. Taking advantage of the fixation effect of a rigid framework, the incorporation of eosin Y into MOF leads to great enhancement of their chemical durability. More importantly, by the introduction of the second auxiliary ligand, the carbonyl groups of xanthene on the eosin Y dyes were perfectly retained and periodically aligned within the confined channels of this rigid framework, which could effectively form excited state radicals to prompt inert C-H bond activation, promoting reaction efficiency by the host-guest supramolecular interaction. New eosin Y-based MOFs were recyclable for six times without reducing photocatalytic activity. This eosin Y functionalized MOF-based heterogeneous photocatalytic system provides an availably catalytic avenue to develop a scalable and sustainable synthetic strategy for the practical application of organic dyes.
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Affiliation(s)
- Liang Zhao
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, P. R. China
| | - Zenggang Du
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, P. R. China
| | - Guanfeng Ji
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, P. R. China
| | - Yefei Wang
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, P. R. China
| | - Wei Cai
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, P. R. China
| | - Cheng He
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, P. R. China
| | - Chunying Duan
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, P. R. China
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