1
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Liang Q, Gao S, Hao W, Zhang G. Palladium-Catalyzed Multicomponent Carbonylation of Halides to Acylhydrazones. J Org Chem 2024; 89:8537-8545. [PMID: 38861493 DOI: 10.1021/acs.joc.4c00451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
The current methods for synthesizing acylhydrazones are limited by their multistep processes, narrow substrate scope, low selectivities, and poor yields. Herein, a fundamentally novel approach to bioactive acylhydrazones was developed based on the palladium-catalyzed multicomponent tandem condensation carbonylation of halides with aldehydes and hydrazines. This method provides a useful and efficient strategy for generating grams of various acylhydrazones in a one-pot manner. Mechanistic studies provided evidence of facile carbonylation of halides with the weak nucleophile hydrazones facilitated by a base.
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Affiliation(s)
- Qianqian Liang
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuo Gao
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wentao Hao
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guoying Zhang
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
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2
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Liu S, Yang Y, Song Q, Liu Z, Lu Y, Wang Z, Sivaguru P, Bi X. Tunable molecular editing of indoles with fluoroalkyl carbenes. Nat Chem 2024; 16:988-997. [PMID: 38443494 DOI: 10.1038/s41557-024-01468-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 01/31/2024] [Indexed: 03/07/2024]
Abstract
Building molecular complexity from simple feedstocks through precise peripheral and skeletal modifications is central to modern organic synthesis. Nevertheless, a controllable strategy through which both the core skeleton and the periphery of an aromatic heterocycle can be modified with a common substrate remains elusive, despite its potential to maximize structural diversity and applications. Here we report a carbene-initiated chemodivergent molecular editing of indoles that allows both skeletal and peripheral editing by trapping an electrophilic fluoroalkyl carbene generated in situ from fluoroalkyl N-triftosylhydrazones. A variety of fluorine-containing N-heterocyclic scaffolds have been efficiently achieved through tunable chemoselective editing reactions at the skeleton or periphery of indoles, including one-carbon insertion, C3 gem-difluoroolefination, tandem cyclopropanation and N1 gem-difluoroolefination, and cyclopropanation. The power of this chemodivergent molecular editing strategy has been highlighted through the modification of the skeleton or periphery of natural products in a controllable and chemoselective manner. The reaction mechanism and origins of the chemo- and regioselectivity have been probed by both experimental and theoretical methods.
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Affiliation(s)
- Shaopeng Liu
- Department of Chemistry, Northeast Normal University, Changchun, China
| | - Yong Yang
- Department of Chemistry, Northeast Normal University, Changchun, China
| | - Qingmin Song
- Department of Chemistry, Northeast Normal University, Changchun, China
| | - Zhaohong Liu
- Department of Chemistry, Northeast Normal University, Changchun, China.
| | - Ying Lu
- Department of Chemistry, Northeast Normal University, Changchun, China
| | - Zhanjing Wang
- Department of Chemistry, Northeast Normal University, Changchun, China
| | | | - Xihe Bi
- Department of Chemistry, Northeast Normal University, Changchun, China.
- State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, China.
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3
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Li L, Sivaguru P, Wei D, Liu M, Zhu Q, Dong S, Casali E, Li N, Zanoni G, Bi X. Silver-catalyzed direct conversion of epoxides into cyclopropanes using N-triftosylhydrazones. Nat Commun 2024; 15:1951. [PMID: 38431716 PMCID: PMC10908805 DOI: 10.1038/s41467-024-46188-w] [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: 09/20/2023] [Accepted: 02/19/2024] [Indexed: 03/05/2024] Open
Abstract
Epoxides, as a prominent small ring O-heterocyclic and the privileged pharmacophores for medicinal chemistry, have recently represented an ideal substrate for the development of single-atom replacements. The previous O-to-C replacement strategy for epoxides to date typically requires high temperatures to achieve low yields and lacks substrate range and functional group tolerance, so achieving this oxygen-carbon exchange remains a formidable challenge. Here, we report a silver-catalyzed direct conversion of epoxides into trifluoromethylcyclopropanes in a single step using trifluoromethyl N-triftosylhydrazones as carbene precursors, thereby achieving oxygen-carbon exchange via a tandem deoxygenation/[2 + 1] cycloaddition. The reaction shows broad tolerance of functional groups, allowing routine cheletropic olefin synthesis in a strategy for the net oxygen-carbon exchange reaction. The utility of this method is further showcased with the late-stage diversification of epoxides derived from bioactive natural products and drugs. Mechanistic experiments and DFT calculations elucidate the reaction mechanism and the origin of the chemo- and stereoselectivity.
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Affiliation(s)
- Linxuan Li
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | | | - Dandan Wei
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Menglin Liu
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Qingwen Zhu
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Shuai Dong
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Emanuele Casali
- Department of Chemistry, University of Pavia, Viale Taramelli 12, 27100, Pavia, Italy
| | - Nan Li
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Giuseppe Zanoni
- Department of Chemistry, University of Pavia, Viale Taramelli 12, 27100, Pavia, Italy
| | - Xihe Bi
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China.
- State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, China.
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4
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Li L, Ning Y, Chen H, Ning Y, Sivaguru P, Liao P, Zhu Q, Ji Y, de Ruiter G, Bi X. Dearomative Insertion of Fluoroalkyl Carbenes into Azoles Leading to Fluoroalkyl Heterocycles with a Quaternary Center. Angew Chem Int Ed Engl 2024; 63:e202313807. [PMID: 37966100 DOI: 10.1002/anie.202313807] [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: 09/18/2023] [Revised: 11/12/2023] [Accepted: 11/13/2023] [Indexed: 11/16/2023]
Abstract
The skeletal ring expansion of heteroarenes through carbene insertion is gaining popularity in synthetic chemistry. Efficient strategies for heterocyclic ring expansion to access heterocycles containing a fluoroalkyl quaternary carbon center through fluoroalkyl carbene insertion are highly desirable because of their broad applications in medicinal chemistry. Herein, we report a general strategy for the dearomative one-carbon insertion of azoles using fluoroalkyl N-triftosylhydrazones as fluoroalkyl carbene precursors, resulting in ring-expanded heterocycles in excellent yields with good functional-group compatibility. The broad generality of this methodology in the late-stage diversification of pharmaceutically interesting bioactive molecules and versatile transformations of the products has been demonstrated.
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Affiliation(s)
- Linxuan Li
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Yongquan Ning
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Hongzhu Chen
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Yongyue Ning
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | | | - Peiqiu Liao
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Qingwen Zhu
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Yong Ji
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Graham de Ruiter
- Schulich Faculty of Chemistry, Technion Israel Institute of Technology, Technion City, 3200008, Haifa, Israel
| | - Xihe Bi
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
- State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, China
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5
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Dongxu Z. Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks. Beilstein J Org Chem 2023; 19:1741-1754. [PMID: 38025086 PMCID: PMC10667715 DOI: 10.3762/bjoc.19.127] [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: 09/02/2023] [Accepted: 11/03/2023] [Indexed: 12/01/2023] Open
Abstract
Nitrogen-containing organofluorine derivatives, which are prepared using fluorinated building blocks, are among the most important active fragments in various pharmaceutical and agrochemical products. This review focuses on the reactivity, synthesis, and applications of fluoromethylated hydrazones and acylhydrazones. It summarizes recent methodologies that have been used for the synthesis of various nitrogen-containing organofluorine compounds.
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Affiliation(s)
- Zhang Dongxu
- Department of Fire Protection Engineering, China Fire and Rescue Institute, Beijing 102202, P. R. of China
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6
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Liu Y, Pang T, Yao W, Zhong F, Wu G. Visible-Light-Induced Radical gem-Iodoallylation of 2,2,2-Trifluorodiazoethane. Org Lett 2023; 25:1958-1962. [PMID: 36912766 DOI: 10.1021/acs.orglett.3c00464] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
A visible-light-induced radical gem-iodoallylation of CF3CHN2 was developed under mild conditions, delivering a variety of α-CF3-substituted homoallylic iodide compounds in moderate to excellent yields. The transformation features broad substrate scope, good functional group compatibility, and operational simplicity. The described protocol provides a convenient and attractive tool to apply CF3CHN2 as CF3-introduction reagent in radical synthetic chemistry.
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Affiliation(s)
- Yu Liu
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, Hubei Engineering Research Center for Biomaterials and Medical Protective Materials, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan 430074, China
| | - Tengfei Pang
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, Hubei Engineering Research Center for Biomaterials and Medical Protective Materials, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan 430074, China
| | - Weijun Yao
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, P.R. China
| | - Fangrui Zhong
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, Hubei Engineering Research Center for Biomaterials and Medical Protective Materials, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan 430074, China
| | - Guojiao Wu
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, Hubei Engineering Research Center for Biomaterials and Medical Protective Materials, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan 430074, China
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7
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Zhang X, Ning Y, Tian C, Zanoni G, Bi X. Asymmetric [2+1] cycloaddition of difluoroalkyl-substituted carbenes with alkenes under rhodium catalysis: Synthesis of chiral difluoroalkyl-substituted cyclopropanes. iScience 2023; 26:105896. [PMID: 36994182 PMCID: PMC10040897 DOI: 10.1016/j.isci.2022.105896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 10/30/2022] [Accepted: 12/22/2022] [Indexed: 02/17/2023] Open
Abstract
Herein, we report a novel strategy for the synthesis of chiral difluoroalkyl-substituted cyclopropanes through enantioselective [2 + 1] cyclopropanation of alkenes and difluoroalkyl-substituted carbenes under rhodium catalysis, wherein the newly designed α, α-difluoro-β-carbonyl ketone N-triftosylhydrazones are used as the difluoroalkyl-substituted carbenes precursors. This approach represents the first asymmetric cyclopropanation of alkenes with difluoroalkyl carbenes, featuring high yield, high enantioselectivity, and broad substrate scope. Gram-scale synthesis and further interconversion of diverse functional groups demonstrate the usefulness of this protocol in the preparation of diverse functionalized chiral difluoroalkyl-substituted cyclopropanes.
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Affiliation(s)
- Xinyu Zhang
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Yongquan Ning
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Chunqi Tian
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Giuseppe Zanoni
- Department of ChemistryUniversity of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
| | - Xihe Bi
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
- State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
- Corresponding author
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8
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Zhang X, Li L, Sivaguru P, Zanoni G, Bi X. Highly electrophilic silver carbenes. Chem Commun (Camb) 2022; 58:13699-13715. [PMID: 36453127 DOI: 10.1039/d2cc04845k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Catalytic carbene transfer reactions are fundamental transformations in modern organic synthesis, which enable direct access to diverse structurally complex molecules. Despite diazo precursors playing a crucial role in catalytic carbene transfer reactions, most reported methodologies take into account only diazoacetates or related compounds. This is primarily because diazoalkanes, unless they contain a resonance stabilizing group, are more susceptible to violent exothermic decomposition. In this feature article, we present an alternative approach to carbene-transfer reactions based on the formation of highly electrophilic silver carbenes from N-sulfonylhydrazones, where the high electrophilicity of silver carbenes stems from the weak interaction between silver and the carbenic carbon. These precursors are readily accessible, stable, and environmentally sustainable. Using the strategy that employs highly electrophilic silver carbenes, it is possible to develop novel intermolecular transformations involving non-stabilized carbenes, including C(sp3)-H insertion, C(sp3)-C(O) insertion, cycloaddition, and defluorinative functionalization. The silver-catalyzed carbene transfer reactions described here have high efficiency, unusual reactivity, exceptional selectivity, and a reaction pathway that differs from typical transition metal-catalyzed reactions. Our research provided fundamental insight into silver carbene chemistry, and we hope to apply this mode of catalysis to other more general transformations, including asymmetric transformations.
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Affiliation(s)
- Xiaolong Zhang
- Department of Chemistry, Northeast Normal University, 5268 Renmin Street, 130024, Changchun, P. R. China.
| | - Linxuan Li
- Department of Chemistry, Northeast Normal University, 5268 Renmin Street, 130024, Changchun, P. R. China.
| | - Paramasivam Sivaguru
- Department of Chemistry, Northeast Normal University, 5268 Renmin Street, 130024, Changchun, P. R. China.
| | - Giuseppe Zanoni
- Department of Chemistry, University of Pavia, Viale Taramelli 12, 27100, Pavia, Italy
| | - Xihe Bi
- Department of Chemistry, Northeast Normal University, 5268 Renmin Street, 130024, Changchun, P. R. China.
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9
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Fang Z, Gong Y, Liu B, Zhang J, Han X, Liu Z, Ning Y. Rh-Catalyzed Coupling Reactions of Fluoroalkyl N-Sulfonylhydrazones with Azides Leading to α-Trifluoroethylated Imines. Org Lett 2022; 24:8920-8924. [DOI: 10.1021/acs.orglett.2c03773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Zhongxue Fang
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng City, Jiangsu 224007, People’s Republic of China
| | - Yanmei Gong
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng City, Jiangsu 224007, People’s Republic of China
| | - Binbin Liu
- Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024, China
| | - Jin Zhang
- Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024, China
| | - Xinyue Han
- Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024, China
| | - Zhaohong Liu
- Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024, China
| | - Yongquan Ning
- Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024, China
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10
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Li L, Zhang X, Ning Y, Zhang X, Liu B, Zhang Z, Sivaguru P, Zanoni G, Li S, Anderson EA, Bi X. Carbodefluorination of fluoroalkyl ketones via a carbene-initiated rearrangement strategy. Nat Commun 2022; 13:4280. [PMID: 35879307 PMCID: PMC9314321 DOI: 10.1038/s41467-022-31976-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 07/12/2022] [Indexed: 11/09/2022] Open
Abstract
The C-F bond cleavage and C-C bond formation (i.e., carbodefluorination) of readily accessible (per)fluoroalkyl groups constitutes an atom-economical and efficient route to partially fluorinated compounds. However, the selective mono-carbodefluorination of trifluoromethyl (CF3) groups remains a challenge, due to the notorious inertness of C-F bond and the risk of over-defluorination arising from C-F bond strength decrease as the defluorination proceeds. Herein, we report a carbene-initiated rearrangement strategy for the carbodefluorination of fluoroalkyl ketones with β,γ-unsaturated alcohols to provide skeletally and functionally diverse α-mono- and α,α-difluoro-γ,δ-unsaturated ketones. The reaction starts with the formation of silver carbenes from fluoroalkyl N-triftosylhydrazones, followed by nucleophilic attack of a β,γ-unsaturated alcohol to form key silver-coordinated oxonium ylide intermediates, which triggers selective C-F bond cleavage by HF elimination and C-C bond formation through Claisen rearrangement of in situ generated difluorovinyl ether. The origin of chemoselectivity and the reaction mechanism are determined by experimental and DFT calculations. Collectively, this strategy by an intramolecular cascade process offers significant advances over existing stepwise strategies in terms of selectivity, efficiency, functional group tolerance, etc.
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Affiliation(s)
- Linxuan Li
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Xinyu Zhang
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Yongquan Ning
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Xiaolong Zhang
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Binbin Liu
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Zhansong Zhang
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | | | - Giuseppe Zanoni
- Department of Chemistry, University of Pavia, Viale Taramelli 12, 27100, Pavia, Italy
| | - Shuang Li
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Edward A Anderson
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Xihe Bi
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China.
- State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, China.
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11
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Liu Z, Sivaguru P, Zanoni G, Bi X. N-Triftosylhydrazones: A New Chapter for Diazo-Based Carbene Chemistry. Acc Chem Res 2022; 55:1763-1781. [PMID: 35675648 DOI: 10.1021/acs.accounts.2c00186] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
ConspectusOver recent decades, N-sulfonylhydrazones have attracted significant attention in academic and industrial contexts owing to their ease of preparation, versatile reactivity, high stability, and practicality. In particular, the use of N-sulfonylhydrazones as precursors for diazo compounds has paved the way for innovative and original organic reactions that are otherwise difficult to achieve. Three key developments are noteworthy in the history of N-sulfonylhydrazone chemistry: (1) Bamford and Stevens initially disclosed the application of N-tosylhydrazones as a diazo source in 1952; (2) Aggarwal and co-workers investigated N-tosylhydrazone salts as diazo precursors for sulfur ylide-mediated asymmetric epoxidation and aziridination in 2001; and (3) Barluenga, Valdés and co-workers first reported Pd-catalyzed cross-coupling reactions with N-tosylhydrazones in 2007, thus introducing the direct use of N-tosylhydrazones in carbene transfer reactions. In the past 2 decades, the synthetic exploration of N-sulfonylhydrazones in carbene chemistry has increased remarkably. N-Tosylhydrazones are the most commonly used N-sulfonylhydrazones, but they are not easy to decompose and normally need relatively high temperatures (e.g., 90-110 °C). Temperature, as a key reaction parameter, has a significant influence on the selectivity and scope of organic reactions, especially the enantioselectivity. Aggarwal and co-workers have addressed this issue by using N-tosylhydrazone salts and achieved a limited number of asymmetric organic reactions, but the method is greatly limited because the salts must be freshly prepared or stored in the dark at -20 °C prior to use. Hence, easily decomposable N-sulfonylhydrazones, especially those capable of decomposing at low temperature, should open up new opportunities for the development of N-sulfonylhydrazone chemistry. Since 2014, our group has worked toward this goal and eventually identified N-2-(trifluoromethyl)benzenesulfonylhydrazone (i.e., N-triftosylhydrazone) as an efficient diazo surrogate that can decompose at temperatures as low as -40 °C. This allowed us to carry out a range of challenging synthetic transformations and to broaden the applications of some known reactions of great relevance.In this Account, we report our achievements in the application of N-triftosylhydrazones in carbene chemistry. On the basis of the reaction types, such applications can be categorized as (i) C(sp3)-H insertion reactions, (ii) defluorinative reactions of fluoroalkyl N-triftosylhydrazones, (iii) cycloaddition reactions with alkenes and alkynes, and (iv) asymmetric reactions. Additional applications in Doyle-Kirmse rearrangements and cross-coupling with isocyanides (ours) and benzyl chlorides (from the group of Xia) are also summarized in this Account concerning miscellaneous reactions. In terms of reaction efficiency, selectivity, and functional group tolerance, N-triftosylhydrazones are generally superior to traditional N-tosylhydrazones because of their easy decomposition. Mechanistic investigations by theoretical calculations provide insights into both the reaction mechanisms and the origin of selectivity. We hope that this Account will inspire broad interest and promote new progress in the synthetic exploration of easily decomposable N-sulfonylhydrazones.
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Affiliation(s)
- Zhaohong Liu
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | | | - Giuseppe Zanoni
- Department of Chemistry, University of Pavia, Pavia 27100, Italy
| | - Xihe Bi
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
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12
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Zhang X, Li L, Zanoni G, Han X, Bi X. Direct gem-Difluoroalkenylation of X-H Bonds with Trifluoromethyl Ketone N-Triftosylhydrazones for Synthesis of Tetrasubstituted Heteroatomic gem-Difluoroalkenes. Chemistry 2022; 28:e202200280. [PMID: 35191565 DOI: 10.1002/chem.202200280] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Indexed: 12/24/2022]
Abstract
The direct gem-difluoroalkenylation of X-H bonds represents the most straightforward approach to access heteroatomic gem-difluoroalkenes that, as the isostere of the carbonyl group, have great potency in drug discovery. However, the construction of tetrasubstituted heteroatomic gem-difluoroalkenes by this strategy is still an unsolved problem. Here, we report the first direct X-H bond gem-difluoroalkenylation of amines and alcohols with trifluoromethyl ketone N-triftosylhydrazones under silver (for (hetero)aryl hydrazones) or rhodium (for alkyl hydrazones), thereby providing a most powerful method for the synthesis of tetrasubstituted heteroatomic gem-difluoroalkenes. This method features a broad substrate scope, high product yield, excellent functional group tolerance, and operational simplicity (open air conditions). Moreover, the site-specific replacement of the carbonyl group with a gem-difluorovinyl ether bioisostere in drug Trimebutine and the post-modification of bioactive molecules demonstrates potential use in medicinal research. Finally, the reaction mechanism was investigated by combining experiments and DFT calculations, and disclosed that the key step of HF elimination occurred via five-membered ring transition state, and the difference in the electrophilicity of Ag- and Rh-carbenes as well as the multiple intermolecular interactions rendered the effectiveness of Rh catalyst selectively for alkyl hydrazones.
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Affiliation(s)
- Xinyu Zhang
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Linxuan Li
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Giuseppe Zanoni
- Department of Chemistry, University of Pavia, Viale Taramelli 12, 27100, Pavia, Italy
| | - Xinyue Han
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China
| | - Xihe Bi
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China.,State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, China
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13
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Fang Z, Jin Q, Wang X, Ning Y. Metal-free [2 + 1 + 3] Cycloaddition of Trifluoroacetaldehyde N-Sulfonylhydrazones with Hexahydro-1,3,5-triazines Leading to Trifluoromethylated 2,3,4,5-Tetrahydro-1,2,4-triazines. J Org Chem 2022; 87:2966-2974. [PMID: 35133818 DOI: 10.1021/acs.joc.1c02810] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A transition-metal-free [2 + 1 + 3] cycloaddition of trifluoroacetaldehyde N-sulfonylhydrazone and hexahydro-1,3,5-triazine was described. This operationally simple protocol provides a general synthesis of diverse trifluoromethylated 2,3,4,5-tetrahydro-1,2,4-triazines in 81-97% yield with a broad substrate scope, including aryl, benzyl, and alkyl hexahydro-1,3,5-triazine.
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Affiliation(s)
- Zhongxue Fang
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng 224007, China
| | - Qihao Jin
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng 224007, China
| | - Xinyu Wang
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Yongquan Ning
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Department of Chemistry, Northeast Normal University, Changchun 130024, China
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14
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Liu Z, Yang Y, Jiang X, Song Q, Zanoni G, Liu S, Bi X. Dearomative [4 + 3] cycloaddition of furans with vinyl- N-triftosylhydrazones by silver catalysis: stereoselective access to oxa-bridged seven-membered bicycles. Org Chem Front 2022. [DOI: 10.1039/d2qo00256f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A practical dearomative [4 + 3] cycloaddition of furans with vinylcarbenes to access oxa-bridged seven-membered carbocycles, with complete and predictable stereoselectivity, is achieved by merging silver catalysis and vinyl-N-triftosylhydrazones.
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Affiliation(s)
- Zhaohong Liu
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Yong Yang
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Xinyu Jiang
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Qingmin Song
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Giuseppe Zanoni
- Department of Chemistry, University of Pavia, Viale Taramelli 12, 27100, Pavia, Italy
| | - Shaopeng Liu
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Xihe Bi
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
- State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
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15
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Fang Z, Ma Y, Liu S, Bai H, Li S, Ning Y, Zanoni G, Liu Z. Silver-catalyzed [4 + 3] cycloaddition of 1,3-dienes with alkenyl- N-triftosylhydrazones: a practical approach to 1,4-cycloheptadienes. Org Chem Front 2022. [DOI: 10.1039/d2qo00806h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A formal [4 + 3] cycloaddition of 1,3-dienes with alkenyl-N-triftosylhydrazones was developed using silver catalysis, producing a broad spectrum of complex 1,4-cycloheptadienes with high yields and predictable stereochemistry.
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Affiliation(s)
- Zhongxue Fang
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng City 224007, People's Republic of China
| | - Yiming Ma
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng City 224007, People's Republic of China
| | - Shaopeng Liu
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Huricha Bai
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Shuang Li
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Yongquan Ning
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Giuseppe Zanoni
- Department of Chemistry, University of Pavia, Viale Taramelli 12, 27100, Pavia, Italy
| | - Zhaohong Liu
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
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16
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Zhang X, Sivaguru P, Zanoni G, Han X, Tong M, Bi X. Catalytic Asymmetric C(sp 3)–H Carbene Insertion Approach to Access Enantioenriched 3-Fluoroalkyl 2,3-Dihydrobenzofurans. ACS Catal 2021. [DOI: 10.1021/acscatal.1c04523] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Xinyu Zhang
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | | | - Giuseppe Zanoni
- Department of Chemistry, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
| | - Xinyue Han
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Minghui Tong
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Xihe Bi
- Department of Chemistry, Northeast Normal University, Changchun 130024, China
- State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
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