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Saha D, Taily IM, Kumar R, Banerjee P. Electrochemical rearrangement protocols towards the construction of diverse molecular frameworks. Chem Commun (Camb) 2021; 57:2464-2478. [PMID: 33616597 DOI: 10.1039/d1cc00116g] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Rearrangement reactions constitute a critical facet of synthetic organic chemistry and demonstrate an attractive way to take advantage of existing structures to access various important molecular frameworks. Electroorganic chemistry has emerged as an environmentally benign approach to carry out organic transformations by directly employing an electric current and avoids the use of stoichiometric chemical oxidants. The last few years have witnessed a resurgence of electroorganic chemistry that has promoted a renaissance of interest in the development of novel redox electroorganic transformations. This review manifests the evolution of electrosynthesis in the area of rearrangement chemistry and covers the achievements in the field of migration, ring expansion, and rearrangements along with the mechanisms involved.
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Affiliation(s)
- Debarshi Saha
- Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab-140001, India.
| | - Irshad Maajid Taily
- Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab-140001, India.
| | - Rakesh Kumar
- Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab-140001, India.
| | - Prabal Banerjee
- Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab-140001, India.
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Lennox AJJ, Nutting JE, Stahl SS. Selective electrochemical generation of benzylic radicals enabled by ferrocene-based electron-transfer mediators. Chem Sci 2018; 9:356-361. [PMID: 29732109 PMCID: PMC5909123 DOI: 10.1039/c7sc04032f] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 10/25/2017] [Indexed: 11/25/2022] Open
Abstract
The generation and intermolecular functionalisation of carbon-centred radicals has broad potential synthetic utility. Herein, we show that benzylic radicals may be generated electrochemically from benzylboronate derivatives at low electrode potentials (ca. -0.3 V vs. Cp2Fe0/+) via single electron oxidation. Use of a catalytic quantity of a ferrocene-based electron-transfer mediator is crucial to achieve successful radical functionalisation and avoid undesirable side reactions arising from direct electrochemical oxidation or from the use of stoichiometric ferrocenium-based oxidants.
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Affiliation(s)
- Alastair J J Lennox
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , USA .
| | - Jordan E Nutting
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , USA .
| | - Shannon S Stahl
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , USA .
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Turygin VV, Tomilov AP. Possible trends in the development of applied electrochemical synthesis of organic compounds (Review). RUSS J ELECTROCHEM+ 2015. [DOI: 10.1134/s1023193515110191] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Ogawa KA, Boydston AJ. Recent Developments in Organocatalyzed Electroorganic Chemistry. CHEM LETT 2015. [DOI: 10.1246/cl.140915] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Francke R, Little RD. Redox catalysis in organic electrosynthesis: basic principles and recent developments. Chem Soc Rev 2014; 43:2492-521. [DOI: 10.1039/c3cs60464k] [Citation(s) in RCA: 1071] [Impact Index Per Article: 107.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Francke R, Little RD. Optimizing electron transfer mediators based on arylimidazoles by ring fusion: synthesis, electrochemistry, and computational analysis of 2-aryl-1-methylphenanthro[9,10-d]imidazoles. J Am Chem Soc 2013; 136:427-35. [PMID: 24328337 DOI: 10.1021/ja410865z] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
A significant improvement of the properties of redox catalysts based on the triarylimidazole framework can be achieved with a simple structural modification. By linking the ortho-carbons of the aromatics positioned at C-4 and C-5, a fused framework is generated, removing the distortion from planarity and enhancing the influence of the substituents on the redox properties. This modification leads not only to a much broader range of available redox potentials for the resulting phenanthro[9,10-d]imidazoles but also to improved stability of the corresponding radical cation. These concepts were verified with eight new phenanthro[9,10-d]imidazole derivatives, using cyclic voltammetry and DFT calculations. For this purpose, an optimized and general synthetic route to the desired compounds was developed. An excellent linear correlation of the calculated effective ionization potentials with the experimental oxidation potentials was obtained, allowing for an accurate prediction of oxidation potentials of derivatives yet to be synthesized. Moreover, high catalytic activity was found for electro-oxidative C-H activation reactions.
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Affiliation(s)
- Robert Francke
- Department of Chemistry and Biochemistry, University of California , Santa Barbara, California 93106-9510, United States
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Morofuji T, Shimizu A, Yoshida JI. Electrochemical C-H amination: synthesis of aromatic primary amines via N-arylpyridinium ions. J Am Chem Soc 2013; 135:5000-3. [PMID: 23510504 DOI: 10.1021/ja402083e] [Citation(s) in RCA: 191] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We have developed a new method for C-H amination of aromatic compounds based on electrochemical oxidation of aromatic compounds in the presence of pyridine followed by the reaction of the resulting N-arylpyridinium ions with an alkylamine. This new transformation serves as a powerful method for synthesizing aromatic primary amines from aromatic compounds without using metal catalysts and harsh chemical reagents. High chemoselectivity of the present method is demonstrated by C-H amination of aromatic compounds bearing a nitro group to give a key intermediate for the synthesis of VLA-4 antagonist.
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Affiliation(s)
- Tatsuya Morofuji
- Department of Synthetic Chemistry, Biological Chemistry, Graduate School of Engineering, Kyoto University , Nishikyo-ku, Kyoto 615-8510, Japan
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Ashikari Y, Nokami T, Yoshida JI. Oxidative hydroxylation mediated by alkoxysulfonium ions. Org Lett 2012; 14:938-41. [PMID: 22273445 DOI: 10.1021/ol203467v] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Oxidative hydroxylation of toluene derivatives via alkoxysulfonium ion intermediates was achieved by integration of anodic oxidation and hydrolysis to give benzyl alcohols which are also susceptible to oxidation. Alkenes were also oxidized to give 1,2-diols without overoxidation. The integration of electrochemical oxidative cyclization and hydrolysis was achieved using alkenes bearing a nitrogen atom in an appropriate position to give cyclic β-amino-substituted alcohols.
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Affiliation(s)
- Yosuke Ashikari
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
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Okada Y, Yamaguchi Y, Chiba K. Efficient Intermolecular Carbon-Carbon Bond-Formation Reactions Assisted by Surface-Condensed Electrodes. European J Org Chem 2011. [DOI: 10.1002/ejoc.201101313] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Okada Y, Yoshioka T, Koike M, Chiba K. Heterogeneous continuous flow synthetic system using cyclohexane-based multiphase electrolyte solutions. Tetrahedron Lett 2011. [DOI: 10.1016/j.tetlet.2011.07.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ashikari Y, Nokami T, Yoshida JI. Integrated electrochemical-chemical oxidation mediated by alkoxysulfonium ions. J Am Chem Soc 2011; 133:11840-3. [PMID: 21744849 DOI: 10.1021/ja202880n] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Generation of carbocations by the "cation pool" method followed by reaction with dimethyl sulfoxide (DMSO) gave the corresponding alkoxysulfonium ions. Alkoxysulfonium ions could also be generated by in situ DMSO trapping of electrochemically generated carbocations. The resulting alkoxysulfonium ions were transformed into carbonyl compounds by treatment with triethylamine. The present integrated electrochemical-chemical oxidation can be applied to the oxidation of diarylmethanes to diaryl ketones, toluenes to benzaldehydes, and aryl-substituted alkenes to 1,2-diketones. Moreover, the oxidation of unsaturated compounds bearing a nucleophilic group in an appropriate position gives cyclized carbonyl compounds.
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Affiliation(s)
- Yosuke Ashikari
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
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Okada Y, Nishimoto A, Akaba R, Chiba K. Electron-Transfer-Induced Intermolecular [2 + 2] Cycloaddition Reactions Based on the Aromatic “Redox Tag” Strategy. J Org Chem 2011; 76:3470-6. [DOI: 10.1021/jo200490q] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yohei Okada
- Department of Applied Life Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Asaki Nishimoto
- Department of Applied Life Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Ryoichi Akaba
- Department of Chemistry, Gunma College of Technology, 580 Toriba-machi, Maebashi, Gunma 371-8530, Japan
| | - Kazuhiro Chiba
- Department of Applied Life Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
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