1
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Tan Y, Pei M, Yang K, Zhou T, Hu A, Guo JJ. Catalytic Generation of Pyridyl Radicals via Electron Donor-Acceptor Complex Photoexcitation: Synthesis of 2-Pyridylindole-Based Heterobiaryls. Org Lett 2024; 26:8084-8089. [PMID: 39287652 DOI: 10.1021/acs.orglett.4c02985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2024]
Abstract
We report the catalytic generation of pyridyl radicals through photoexcitation of the electron donor-acceptor (EDA) complex, which enables the C2-selective heteroarylation of indole under ambient conditions. In this manifold, catalytic triarylamine and chloropyridine aggregate into an EDA complex in the presence of an inorganic base, making readily available chloropyridines good precursors for the generation of diverse pyridyl radicals. Given the broad reaction scope, this catalytic EDA complex protocol provides robust access to heterobiaryl scaffolds that are widely present in biologically important molecules.
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Affiliation(s)
- Yingfei Tan
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China
| | - Meiting Pei
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China
| | - Kang Yang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China
| | - Tingting Zhou
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China
| | - Anhua Hu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China
| | - Jing-Jing Guo
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, China
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2
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Zhang SP, Guo DW, Yang ML, Xia YT, Yang WC. EDA Complex-Enabled Annulation to Access CF 2-Containing Tetralones and Quinazolinones Using Persulfates as Electron Donors. J Org Chem 2024; 89:10614-10623. [PMID: 39051432 DOI: 10.1021/acs.joc.4c00845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
A photocatalyst-free and EDA complex-enabled radical cascade cyclization reaction of inactive alkenes with bromodifluoroacetamides was reported for the divergent synthesis of fluorine-containing tetralones and quinazolinones. In this transformation, persulfates as electron donors and difluoro bromamide as electron acceptors generate the EDA complex. This is a promising photochemical method with advantages such as mild reaction conditions, simple operation, being metal-free, and excellent functional group tolerance.
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Affiliation(s)
- Shu-Peng Zhang
- Guangling College and School of Plant Protection, Yangzhou University, Yangzhou 225009, P. R. China
| | - Da-Wei Guo
- Guangling College and School of Plant Protection, Yangzhou University, Yangzhou 225009, P. R. China
| | - Mei-Ling Yang
- Guangling College and School of Plant Protection, Yangzhou University, Yangzhou 225009, P. R. China
| | - Yun-Tao Xia
- College of Chemistry & Chemical Engineering, Henan University of Technology, Academician Workstation for Natural Medicinal Chemistry of Henan Province, Zhengzhou 450001, China
| | - Wen-Chao Yang
- Guangling College and School of Plant Protection, Yangzhou University, Yangzhou 225009, P. R. China
- Key Laboratory of Green and Precise Synthetic Chemistry, Ministry of Education, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China
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3
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Mondal M, Ghosh S, Lai D, Hajra A. C-H Functionalization of Heteroarenes via Electron Donor-Acceptor Complex Photoactivation. CHEMSUSCHEM 2024:e202401114. [PMID: 38975970 DOI: 10.1002/cssc.202401114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Revised: 07/05/2024] [Accepted: 07/08/2024] [Indexed: 07/09/2024]
Abstract
C-H Functionalization of heteroarenes stands as a potent instrument in organic synthesis, and with the incorporation of visible light, it emerged as a transformative game-changer. In this domain, electron donor-acceptor (EDA) complex, formed through the pairing of an electron-rich substrate with an electron-accepting molecule, has garnered substantial consideration in recent years due to the related avoidance of the requirement of photocatalyst as well as oxidant. EDA complexes can undergo photoactivation under mild conditions and exhibit high functional group tolerance, making them potentially suitable for the functionalization of biologically relevant heteroarenes. This review article provides an overview of recent advancements in the field of C-H functionalization of heteroarenes via EDA complex photoactivation with literature coverage up to April, 2024.
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Affiliation(s)
- Madhusudan Mondal
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, 731235, India
| | - Sumit Ghosh
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, 731235, India
| | - Dipti Lai
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, 731235, India
| | - Alakananda Hajra
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, 731235, India
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4
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Romero IE, Barata-Vallejo S, Bonesi SM, Postigo A. Perfluoroalkylation of Triarylamines by EDA Complexes and Ulterior Sensitized [6π]-Electrocyclization to Perfluoroalkylated Endo-Carbazoles. Mechanistic and Photophysical Studies. Chemistry 2024; 30:e202400905. [PMID: 38536766 DOI: 10.1002/chem.202400905] [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: 03/04/2024] [Indexed: 04/18/2024]
Abstract
Blue LEDs-irradiation of a mixture of N,N,N',N'-tetramethylethylenediamine (TMEDA) and perfluoroalkyl iodides (RF-I) - Electron Donor Acceptor (EDA)-complex - in the presence of triphenylamines (TPAs) in an aqueous solvent mixture afforded mono-perfluoroalkylated triphenylamines (RF-TPA) in good yields. These RF-TPA were further subjected to acetone-sensitized [6π]-electrocyclization at 315 nm-irradiation affording exclusively perfluoroalkylated endo-carbazole derivatives (RF-CBz) in quantitative yields. Mechanistic studies and photophysical properties of products are studied.
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Affiliation(s)
- Ivan E Romero
- Departamento de Ciencias Químicas, CONICET-Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junin 954, Buenos Aires, CP 1113, Argentina
- Departamento de Química Orgánica Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires Ciudad Universitaria, Buenos Aires, C1428EGA, Argentina
- CONICET-Universidad de Buenos Aires, Centro de Investigaciones en Hidratos de Carbono. (CIHIDECAR), Ciudad Universitaria, Buenos Aires, C1428EGA, Argentina
| | - Sebastian Barata-Vallejo
- Departamento de Ciencias Químicas, CONICET-Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junin 954, Buenos Aires, CP 1113, Argentina
- Istituto per la Sintesi Organica e la Fotoreattività ISOF, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129, Bologna, Italy
| | - Sergio M Bonesi
- Departamento de Química Orgánica Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires Ciudad Universitaria, Buenos Aires, C1428EGA, Argentina
- CONICET-Universidad de Buenos Aires, Centro de Investigaciones en Hidratos de Carbono. (CIHIDECAR), Ciudad Universitaria, Buenos Aires, C1428EGA, Argentina
| | - Al Postigo
- Departamento de Ciencias Químicas, CONICET-Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junin 954, Buenos Aires, CP 1113, Argentina
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5
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Wang Y, Fan S, Tang X. Nucleophilic Organocatalyst for Photochemical Carbon Radical Generation via S N2 Substitution. Org Lett 2024; 26:4002-4007. [PMID: 38691539 DOI: 10.1021/acs.orglett.4c01278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
Photochemical generation of radicals is a powerful way to construct various molecules. But most of these methods rely on initiators or the redox properties of radical precursors. Herein, we report a photochemical organic catalyst that reacts with benzyl halide to generate carbon radical via an SN2 pathway. This nucleophilic catalyst can be easily prepared and is bench-stable. The SN2 process does not rely on the redox properties of halides, showing potential synthetic utility. Control experiments and UV-vis spectroscopic analysis indicate that the SN2 substitution adduct is the key intermediate.
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Affiliation(s)
- Yuzhuo Wang
- Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Shiwen Fan
- Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Xinjun Tang
- Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
- Zhejiang Institute, China University of Geosciences, Hangzhou 311305, China
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6
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Huang XL, Zhang DL, Li Q, Xie ZB, Le ZG, Zhu ZQ. Visible-Light-Induced C-H Cyanoalkylation of Azauracils with Cycloketone Oxime Esters via Catalytic EDA Complex. Org Lett 2024; 26:3727-3732. [PMID: 38678575 DOI: 10.1021/acs.orglett.4c00742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
Photoexcitation electron donor-acceptor (EDA) complexes provide an effective approach to produce radicals under mild conditions, while the catalytic version of EDA complex photoactivation remains scarce. Herein, we report a visible-light-induced organophotocatalytic pathway for the cyanoalkylation of azauracils using inexpensive and readily available 1,4-diazabicyclo[2.2.2]octane (DABCO) as a catalytic electron donor. This synthetic method exhibits exceptional compatibility with various functional groups and presents 34 examples in high yields. The efficient cyanoalkylation offers an environmentally friendly and sustainable route toward enhancing the structural and functional diversity of azauracils.
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Affiliation(s)
- Xiao-Long Huang
- Jiangxi Province Key Laboratory of Synthetic Chemistry, School of Chemistry and Materials Science, East China University of Technology, Nanchang, 330013, China
| | - Dong-Liang Zhang
- Jiangxi Province Key Laboratory of Synthetic Chemistry, School of Chemistry and Materials Science, East China University of Technology, Nanchang, 330013, China
| | - Qing Li
- Jiangxi Province Key Laboratory of Synthetic Chemistry, School of Chemistry and Materials Science, East China University of Technology, Nanchang, 330013, China
| | - Zong-Bo Xie
- Jiangxi Province Key Laboratory of Synthetic Chemistry, School of Chemistry and Materials Science, East China University of Technology, Nanchang, 330013, China
| | - Zhang-Gao Le
- Jiangxi Province Key Laboratory of Synthetic Chemistry, School of Chemistry and Materials Science, East China University of Technology, Nanchang, 330013, China
| | - Zhi-Qiang Zhu
- Jiangxi Province Key Laboratory of Synthetic Chemistry, School of Chemistry and Materials Science, East China University of Technology, Nanchang, 330013, China
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7
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Zhang DL, Le ZG, Li Q, Xie ZB, Yang WW, Zhu ZQ. Visible-light-driven EDA complex-promoted cascade cyclization to construct 4-cyanoalkyl isoquinoline-1,3-diones. Chem Commun (Camb) 2024; 60:2958-2961. [PMID: 38375889 DOI: 10.1039/d4cc00092g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Visible-light-induced EDA complex-promoted ring-opening of cycloketone oxime esters to synthesise various cyanoalkylated products with N-methacryloyl benzamides was developed. Various radical receptors were compatible with the current reaction system to furnish diverse heterocyclic compounds. Mechanistic analysis shows that the formation of an EDA complex was crucial to the photocatalytic strategy. Importantly, 4-cyanoalkyl isoquinoline-1,3-diones were obtained in high yields by using a catalytic amount of 1,4-diazabicyclo[2.2.2]octane (DABCO) through prolonging the reaction time, which provided a practical approach to give a variety of isoquinoline-1,3-dione derivatives.
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Affiliation(s)
- Dong-Liang Zhang
- Jiangxi Province Key Laboratory of Synthetic Chemistry, School of Chemistry and Material Science, East China University of Technology, Nanchang, 330013, Jiangxi, China.
| | - Zhang-Gao Le
- Jiangxi Province Key Laboratory of Synthetic Chemistry, School of Chemistry and Material Science, East China University of Technology, Nanchang, 330013, Jiangxi, China.
| | - Qing Li
- Jiangxi Province Key Laboratory of Synthetic Chemistry, School of Chemistry and Material Science, East China University of Technology, Nanchang, 330013, Jiangxi, China.
| | - Zong-Bo Xie
- Jiangxi Province Key Laboratory of Synthetic Chemistry, School of Chemistry and Material Science, East China University of Technology, Nanchang, 330013, Jiangxi, China.
| | - Wen-Wen Yang
- Jiangxi Province Key Laboratory of Synthetic Chemistry, School of Chemistry and Material Science, East China University of Technology, Nanchang, 330013, Jiangxi, China.
| | - Zhi-Qiang Zhu
- Jiangxi Province Key Laboratory of Synthetic Chemistry, School of Chemistry and Material Science, East China University of Technology, Nanchang, 330013, Jiangxi, China.
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8
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Zhao H, Zong Y, Sun Y, An G, Wang J. An Organocatalytic System for Z-Alkene Synthesis via a Hydrogen-Bonding-Assisted Photoinduced Electron Donor-Acceptor Complex. Org Lett 2024; 26:1739-1744. [PMID: 38367258 DOI: 10.1021/acs.orglett.4c00433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2024]
Abstract
A general catalytic donor for the combination of a photoinduced electron donor-acceptor (EDA) complex and energy transfer was developed. This mild and metal-free protocol allows facile access to various Z-alkenes. Mechanism studies revealed that the organophotocatalyst, 4-CzIPN, formed a distinct three-component EDA complex with redox-active esters and (C6H5O)2P(O)OH to trigger the photoredox catalysis. The E → Z isomerization was achieved via electron exchange energy transfer from 4-CzIPN.
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Affiliation(s)
- Hui Zhao
- School of Chemistry and Materials Science, Heilongjiang University, Harbin, Heilongjiang 150080, P. R.China
| | - Yingxiao Zong
- Key Laboratory of Hexi Corridor Resources Utilization of Gansu, College of Chemistry and Chemical Engineering, Hexi University, Zhangye, Gansu 734000, P. R. China
| | - Yue Sun
- School of Chemistry and Materials Science, Heilongjiang University, Harbin, Heilongjiang 150080, P. R.China
| | - Guanghui An
- School of Chemistry and Materials Science, Heilongjiang University, Harbin, Heilongjiang 150080, P. R.China
| | - Junke Wang
- Key Laboratory of Hexi Corridor Resources Utilization of Gansu, College of Chemistry and Chemical Engineering, Hexi University, Zhangye, Gansu 734000, P. R. China
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9
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Lasso JD, Castillo-Pazos DJ, Salgado JM, Ruchlin C, Lefebvre L, Farajat D, Perepichka DF, Li CJ. A General Platform for Visible Light Sulfonylation Reactions Enabled by Catalytic Triarylamine EDA Complexes. J Am Chem Soc 2024; 146:2583-2592. [PMID: 38232387 DOI: 10.1021/jacs.3c11225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Catalytic electron donor-acceptor (EDA) complexes have recently emerged as a powerful and sustainable alternative to iridium- and ruthenium-based photoredox synthetic methods. Yet, these complexes remain underexplored and reliant on the use of meticulously designed acceptors that require previous installation. Herein, we report a novel EDA complex employing tris(4-methoxyphenyl) amine as a catalytic donor for the sulfonylation of alkenes using inexpensive and readily available sulfonyl chlorides. Applying this operationally simple, visible-light-mediated general platform, we report both the redox-neutral and net-reductive functionalization of more than 60 substrates, encompassing vinylic or allylic sulfonylation, hydrosulfonylation, and sulfamoylation of activated and unactivated alkenes and alkynes.
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Affiliation(s)
- Juan D Lasso
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
- FRQNT Centre for Green Chemistry and Catalysis, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Durbis J Castillo-Pazos
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
- FRQNT Centre for Green Chemistry and Catalysis, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Jan Michael Salgado
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
- FRQNT Centre for Green Chemistry and Catalysis, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Cory Ruchlin
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Loric Lefebvre
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
- FRQNT Centre for Green Chemistry and Catalysis, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Daliah Farajat
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
- FRQNT Centre for Green Chemistry and Catalysis, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Dmytro F Perepichka
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Chao-Jun Li
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
- FRQNT Centre for Green Chemistry and Catalysis, McGill University, Montreal, Quebec H3A 0B8, Canada
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10
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Zhu XL, Wang H, Zhai CK, He W. Photo-induced C(sp 2)-H difluoroalkylation of anilines. Org Biomol Chem 2024; 22:720-724. [PMID: 38165818 DOI: 10.1039/d3ob01757e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
A photoinduced protocol for the direct difluoroalkylation of C(sp2)-H bonds in anilines under catalyst-free reaction conditions is presented. This transformation is characterized by a wide substrate scope, mild reaction conditions, and operational simplicity, and could serve as an alternative tool to established methods for the synthesis of difluoroalkylated anilines. Mechanistic studies suggest the formation of an electron-donor-acceptor (EDA) complex between anilines and difluoroalkyl bromides in this reaction.
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Affiliation(s)
- Xing-Li Zhu
- Department of Chemistry, School of Pharmacy, Air Force Medical University, Xi'an 710032, P.R.China.
| | - Hua Wang
- Department of Chemistry, School of Pharmacy, Air Force Medical University, Xi'an 710032, P.R.China.
| | - Chen-Kai Zhai
- Department of Chemistry, School of Pharmacy, Air Force Medical University, Xi'an 710032, P.R.China.
| | - Wei He
- Department of Chemistry, School of Pharmacy, Air Force Medical University, Xi'an 710032, P.R.China.
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11
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Xu J, Yang RY, Xu B. Chameleonic Reactivity of Imidoyl Sulfoxonium Ylides: Access to Functionalized Pyrroles and Dihydro-pyridines. Org Lett 2024; 26:62-67. [PMID: 38170926 DOI: 10.1021/acs.orglett.3c03625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
We have found a chameleonic reactivity of imidoyl sulfoxonium ylides. On the one hand, imidoyl sulfoxonium ylides react with electron-deficient reagents, such as alkynyl esters, to lead to the formation of 1,2-dihydro-pyridines. The methyl group attached to the sulfur atom acts as a methylene donor. On the other hand, imidoyl sulfoxonium ylides react with pyridinium 1,4-zwitterionic thiolates, which leads to the formation of functionalized pyrroles. Both transformations feature mild reaction conditions and good functional group tolerance.
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Affiliation(s)
- Jingnan Xu
- Key Laboratory of Science and Technology of Eco-Textiles, Ministry of Education, College of Chemistry and Chemical Engineering, Donghua University, Shanghai 201620, China
| | - Ren-Yin Yang
- Key Laboratory of Science and Technology of Eco-Textiles, Ministry of Education, College of Chemistry and Chemical Engineering, Donghua University, Shanghai 201620, China
| | - Bo Xu
- Key Laboratory of Science and Technology of Eco-Textiles, Ministry of Education, College of Chemistry and Chemical Engineering, Donghua University, Shanghai 201620, China
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12
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Chen YX, He JT, Wu MC, Liu ZL, Xia PJ, Chen K, Xiang HY, Yang H. Visible-light-driven oxidation of organosilanes by a charge-transfer complex. Chem Commun (Camb) 2023; 59:6588-6591. [PMID: 37190787 DOI: 10.1039/d3cc01972a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Direct oxidation of organosilanes is one of the most straightforward ways to access silanols. Herein, we describe a novel photo-induced strategy for oxidation of organosilanes to access silanols, promoted by a photoactive charge-transfer complex (CTC) between sodium benzenesulfinate and molecular O2. A streamlined sequence transformation of organosilanes to silyl ethers was also readily achieved. This developed protocol represents the first example of CTC-based oxidation of organosilanes, offering a facile approach to access a series of silanol and silyl ether products.
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Affiliation(s)
- Yi-Xuan Chen
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China.
| | - Jun-Tao He
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China.
| | - Mei-Chun Wu
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China.
- College of Chemistry and Chemical Engineering, Huaihua University, Huaihua 418008, P. R. China
| | - Zhi-Lin Liu
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China.
| | - Peng-Ju Xia
- School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, P. R. China
| | - Kai Chen
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China.
| | - Hao-Yue Xiang
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China.
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, Henan, P. R. China
| | - Hua Yang
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China.
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