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Yue Y, Guo X, Zhang J, Zhang Z, Zhang Y, Tang Q, Bai R, Yi H, Liu J. Electrochemical Oxidation Enables Radical Dearomative Spiroannulation to 2H-Spiro[benzofuran-3,9'-fluoren]-2-one. Chemistry 2024; 30:e202401303. [PMID: 38794842 DOI: 10.1002/chem.202401303] [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: 04/02/2024] [Revised: 05/19/2024] [Accepted: 05/20/2024] [Indexed: 05/26/2024]
Abstract
Developing pragmatic strategies for accessing functional benzofuran-2-ones from 3-([1,1'-biphenyl]-2-yl)benzofuran remains an enduring challenge. Herein, we have achieved a highly discriminating electrochemical oxidative dearomative spiroannulation of 3-([1,1'-biphenyl]-2-yl)benzofuran, culminating in the synthesis of 2H-spiro[benzofuran-3,9'-fluoren]-2-one derivatives. By harnessing the electrophilic intermediates of benzofuryl radical cations supported by DFT calculations, we attain exceptional regioselectivity while eliminating the need for stoichiometric oxidants. Mechanistic investigations reveal a sequence of events involving the benzofuran radical cation, encompassing the capture of H2O, nucleophilic arene attack, and subsequent deprotonation, ultimately yielding the final benzofuran-2-ones.
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Affiliation(s)
- Yuanyuan Yue
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, P.R. China
| | - Xiaohui Guo
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, P.R. China
| | - Jianhang Zhang
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, P.R. China
| | - Zhiqiang Zhang
- The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, Hubei, P. R. China
| | - Yilin Zhang
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, P.R. China
| | - Qinghu Tang
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, P.R. China
| | - Ruopeng Bai
- School of Chemistry and Chemical Engineering, Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing, 401331, P. R. China
| | - Hong Yi
- The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, Hubei, P. R. China
| | - Jianming Liu
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, P.R. China
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Brufani G, Di Erasmo B, Li CJ, Vaccaro L. Csp 2-H functionalization of phenols: an effective access route to valuable materials via Csp 2-C bond formation. Chem Sci 2024; 15:3831-3871. [PMID: 38487228 PMCID: PMC10935747 DOI: 10.1039/d4sc00687a] [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: 01/29/2024] [Accepted: 02/02/2024] [Indexed: 03/17/2024] Open
Abstract
In the vast majority of top-selling pharmaceutical and industrial products, phenolic structural motifs are highly prevalent. Non-functionalized simple phenols serve as building blocks in the synthesis of value-added chemicals. It is worth mentioning that lignin, being the largest renewable biomass source of aromatic building blocks in nature, mainly consists of phenolic units, which enable the production of structurally diverse phenols. Given their remarkable applicability in the chemical value chain, many efforts have been devoted to increasing the molecular complexity of the phenolic scaffold. Among the key techniques, direct functionalization of Csp2-H is a powerful tool, enabling the construction of new Csp2-C bonds in an economical and atomic manner. Herein we present and summarize the large plethora of direct Csp2-H functionalization methods that enables scaffold diversification of simple, unprotected phenols, leading to the formation of new Csp2-C bonds. In this review article, we intend to summarize the contributions that appeared in the literature mainly in the last 5 years dealing with the functionalization of unprotected phenols, both catalytic and non-catalytic. Our goal is to highlight the key findings and the ongoing challenges in the stimulating and growing research dedicated to the development of new protocols for the valorization of phenols.
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Affiliation(s)
- Giulia Brufani
- Laboratory of Green S.O.C., Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia Via Elce di Sotto 8 06123 Perugia Italy https://greensoc.chm.unipg.it
| | - Benedetta Di Erasmo
- Laboratory of Green S.O.C., Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia Via Elce di Sotto 8 06123 Perugia Italy https://greensoc.chm.unipg.it
- Department of Chemistry, FRQNT Centre for Green Chemistry and Catalysis, McGill University 801 Sherbrooke Street West Montreal QC H3A0B8 Canada
| | - Chao-Jun Li
- Department of Chemistry, FRQNT Centre for Green Chemistry and Catalysis, McGill University 801 Sherbrooke Street West Montreal QC H3A0B8 Canada
| | - Luigi Vaccaro
- Laboratory of Green S.O.C., Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia Via Elce di Sotto 8 06123 Perugia Italy https://greensoc.chm.unipg.it
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Li Y, Huang Y, Li Z, Sun J. Recent Advances in Regioselective C-H Bond Functionalization of Free Phenols. Molecules 2023; 28:molecules28083397. [PMID: 37110630 PMCID: PMC10143084 DOI: 10.3390/molecules28083397] [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: 03/17/2023] [Revised: 04/08/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023] Open
Abstract
Phenols are important readily available synthetic building blocks and starting materials for organic synthetic transformations, which are widely found in agrochemicals, pharmaceuticals, and functional materials. The C-H functionalization of free phenols has proven to be an extremely useful tool in organic synthesis, which provides efficient increases in phenol molecular complexity. Therefore, approaches to functionalizing existing C-H bonds of free phenols have continuously attracted the attention of organic chemists. In this review, we summarize the current knowledge and recent advances in ortho-, meta-, and para-selective C-H functionalization of free phenols in the last five years.
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Affiliation(s)
- Yanan Li
- School of Chemical Engineering, Anhui University of Science and Technology, Huainan 232001, China
| | - Yekai Huang
- School of Chemical Engineering, Anhui University of Science and Technology, Huainan 232001, China
| | - Zhi Li
- School of Chemical Engineering, Anhui University of Science and Technology, Huainan 232001, China
| | - Jianan Sun
- School of Biomedical Engineering, Anhui Medical University, Hefei 230032, China
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Wang Y, Xu N, Li W, Li J, Huo Y, Zhu W, Liu Q. Synthesis of 1,3-diselenyl-dihydroisobenzofurans via electrochemical radical selenylation with substituted o-divinylbenzenes and diselenides. Org Biomol Chem 2022; 20:2813-2817. [PMID: 35319056 DOI: 10.1039/d2ob00254j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
An efficient electrochemical method for the direct synthesis of complicated 1,3-diselenyl-dihydroisobenzofurans was developed under external oxidant free conditions at room temperature from substituted o-divinylbenzenes and diselenides. A radical mechanism is proposed for this novel and practical transformation.
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Affiliation(s)
- Ying Wang
- Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Jiangsu Ocean University; School of Pharmacy, Jiangsu Ocean University, Lianyungang, 222005, Jiangsu, China.
| | - Ning Xu
- School of Metallurgy and Environment, Central South University, Changsha, 410083, Hunan, China
| | - Weiwei Li
- Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Jiangsu Ocean University; School of Pharmacy, Jiangsu Ocean University, Lianyungang, 222005, Jiangsu, China.
| | - Jiaojiao Li
- Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Jiangsu Ocean University; School of Pharmacy, Jiangsu Ocean University, Lianyungang, 222005, Jiangsu, China.
| | - Yijun Huo
- Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Jiangsu Ocean University; School of Pharmacy, Jiangsu Ocean University, Lianyungang, 222005, Jiangsu, China.
| | - Wenrong Zhu
- Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Jiangsu Ocean University; School of Pharmacy, Jiangsu Ocean University, Lianyungang, 222005, Jiangsu, China.
| | - Qiang Liu
- Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, Jiangsu Ocean University; School of Pharmacy, Jiangsu Ocean University, Lianyungang, 222005, Jiangsu, China.
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