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Fan ZH, Kang JX, Jia S, Pan QJ, Cao L, Chen XM, Xu CQ, Ma YN, Chen X. Triborane (B 3H 7)-mediated regioselective substitution reactions of pyridine derivatives. Chem Sci 2024:d4sc03109a. [PMID: 39139736 PMCID: PMC11317908 DOI: 10.1039/d4sc03109a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Accepted: 07/18/2024] [Indexed: 08/15/2024] Open
Abstract
There exists an interplay between borane and a Lewis base in their adducts. However, studies on these adducts so far have mainly focused on the different reactions of B-H bonds with limited attention given to the influence of borane on the chemistry of the Lewis base, except for BF3 and BAr3. Herein, we have synthesized novel borane adducts with pyridine derivatives, Py·B3H7, in which the coordination of B3H7 efficiently achieved the intra-molecular charge transfer. The strong B-N bond in these adducts resulted in the formation of stable dearomatic intermediates of pyridine derivatives, confirmed by 1H and 11B NMR spectroscopy, from which different reactions have transpired to realize C(sp3)-H and C(sp2)-H functionalization under mild conditions. The B3H7 pyridine derivatives are stable and do not dissociate or decompose during the reaction process. The high stability of the B-N bond makes this method a good option for boron-containing drugs with potential for use in boron neutron capture therapy (BNCT).
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Affiliation(s)
- Zi-Heng Fan
- School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Materials, Henan Normal University Xinxiang Henan 453007 China
| | - Jia-Xin Kang
- School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Materials, Henan Normal University Xinxiang Henan 453007 China
| | - Sihan Jia
- School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Materials, Henan Normal University Xinxiang Henan 453007 China
| | - Qiao-Jing Pan
- School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Materials, Henan Normal University Xinxiang Henan 453007 China
| | - Lei Cao
- School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Materials, Henan Normal University Xinxiang Henan 453007 China
| | - Xi-Meng Chen
- School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Materials, Henan Normal University Xinxiang Henan 453007 China
| | - Cong-Qiao Xu
- Department of Chemistry, Southern University of Science and Technology Shenzhen 518055 China
| | - Yan-Na Ma
- College of Chemistry, Zhengzhou University Zhengzhou Henan 450001 China
| | - Xuenian Chen
- School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Materials, Henan Normal University Xinxiang Henan 453007 China
- College of Chemistry, Zhengzhou University Zhengzhou Henan 450001 China
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2
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Guo SM, Xu P, Studer A. Meta-Selective Copper-Catalyzed C-H Arylation of Pyridines and Isoquinolines through Dearomatized Intermediates. Angew Chem Int Ed Engl 2024; 63:e202405385. [PMID: 38634294 DOI: 10.1002/anie.202405385] [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: 03/19/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 04/19/2024]
Abstract
C(sp2)-H functionalization offers an efficient strategy for the synthesis of various elaborated N-containing heteroarenes. Along these lines, oxazino pyridines that can be readily prepared from pyridines, have been introduced as powerful substrates in radical- and ionic-mediated meta-C-H functionalization. However, the regioselective meta-C-H arylation of pyridines remains a great challenge. Herein, a copper-catalyzed meta-selective C-H arylation of pyridines and isoquinolines through bench-stable dearomatized intermediates is reported. Electrophilic aryl-Cu(III) species, generated from readily accessible aryl I(III) reagents, enable the efficient meta-arylation of a broad range of pyridines and isoquinolines. The method also allows the meta-selective alkenylation of these heteroarenes using the corresponding alkenyl I(III)-reagents. Late-stage arylation of drug-derived pyridines and larger-scale experiments demonstrate the potential of this synthetic methodology.
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Affiliation(s)
- Shu-Min Guo
- Organisch-Chemisches Institut, Universität Münster, 48149, Münster, Germany
| | - Pengwei Xu
- Organisch-Chemisches Institut, Universität Münster, 48149, Münster, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, Universität Münster, 48149, Münster, Germany
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3
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Cao VD, Joung S. Synthesis and utility of N-boryl and N-silyl enamines derived from the hydroboration and hydrosilylation of N-heteroarenes and N-conjugated compounds. Front Chem 2024; 12:1414328. [PMID: 38911995 PMCID: PMC11190178 DOI: 10.3389/fchem.2024.1414328] [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: 04/08/2024] [Accepted: 05/17/2024] [Indexed: 06/25/2024] Open
Abstract
Catalytic hydroboration and hydrosilylation have emerged as promising strategies for the reduction of unsaturated hydrocarbons and carbonyl compounds, as well as for the dearomatization of N-heteroarenes. Various catalysts have been employed in these processes to achieve the formation of reduced products via distinct reaction pathways and intermediates. Among these intermediates, N-silyl enamines and N-boryl enamines, which are derived from hydrosilylation and hydroboration, are commonly underestimated in this reduction process. Because these versatile intermediates have recently been utilized in situ as nucleophilic reagents or dipolarophiles for the synthesis of diverse molecules, an expeditious review of the synthesis and utilization of N-silyl and N-boryl enamines is crucial. In this review, we comprehensively discuss a wide range of hydrosilylation and hydroboration catalysts used for the synthesis of N-silyl and N-boryl enamines. These catalysts include main-group metals (e.g., Mg and Zn), transition metals (e.g., Rh, Ru, and Ir), earth-abundant metals (e.g., Fe, Co, and Ni), and non-metal catalysts (including P, B, and organocatalysts). Furthermore, we highlight recent research efforts that have leveraged these versatile intermediates for the synthesis of intriguing molecules, offering insights into future directions for these invaluable building blocks.
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Affiliation(s)
| | - Seewon Joung
- Department of Chemistry, Inha University, Incheon, Republic of Korea
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4
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Xu P, Wang Z, Guo SM, Studer A. Introduction of the difluoromethyl group at the meta- or para-position of pyridines through regioselectivity switch. Nat Commun 2024; 15:4121. [PMID: 38750008 PMCID: PMC11096164 DOI: 10.1038/s41467-024-48383-1] [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] [Accepted: 04/30/2024] [Indexed: 05/18/2024] Open
Abstract
Difluoromethyl pyridines have gained significant attention in medicinal and agricultural chemistry. The direct C-H-difluoromethylation of pyridines represents a highly efficient economic way to access these azines. However, the direct meta-difluoromethylation of pyridines has remained elusive and methods for site-switchable regioselective meta- and para-difluoromethylation are unknown. Here, we demonstrate the meta-C-H-difluoromethylation of pyridines through a radical process by using oxazino pyridine intermediates, which are easily accessed from pyridines. The selectivity can be readily switched to para by in situ transformation of the oxazino pyridines to pyridinium salts upon acid treatment. The preparation of various meta- and para-difluoromethylated pyridines through this approach is presented. The mild conditions used also allow for the late-stage meta- or para-difluoromethylation of pyridine containing drugs. Sequential double functionalization of pyridines is presented, which further underlines the value of this work.
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Affiliation(s)
- Pengwei Xu
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse 40, 48149, Münster, Germany
| | - Zhe Wang
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse 40, 48149, Münster, Germany
| | - Shu-Min Guo
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse 40, 48149, Münster, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, Universität Münster, Corrensstrasse 40, 48149, Münster, Germany.
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5
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Cheng Q, Bhattacharya D, Haring M, Cao H, Mück-Lichtenfeld C, Studer A. Skeletal editing of pyridines through atom-pair swap from CN to CC. Nat Chem 2024; 16:741-748. [PMID: 38238464 PMCID: PMC11087273 DOI: 10.1038/s41557-023-01428-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 12/15/2023] [Indexed: 05/12/2024]
Abstract
Skeletal editing is a straightforward synthetic strategy for precise substitution or rearrangement of atoms in core ring structures of complex molecules; it enables quick diversification of compounds that is not possible by applying peripheral editing strategies. Previously reported skeletal editing of common arenes mainly relies on carbene- or nitrene-type insertion reactions or rearrangements. Although powerful, efficient and applicable to late-stage heteroarene core structure modification, these strategies cannot be used for skeletal editing of pyridines. Here we report the direct skeletal editing of pyridines through atom-pair swap from CN to CC to generate benzenes and naphthalenes in a modular fashion. Specifically, we use sequential dearomatization, cycloaddition and rearomatizing retrocycloaddition reactions in a one-pot sequence to transform the parent pyridines into benzenes and naphthalenes bearing diversified substituents at specific sites, as defined by the cycloaddition reaction components. Applications to late-stage skeletal diversification of pyridine cores in several drugs are demonstrated.
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Affiliation(s)
- Qiang Cheng
- Organisch-Chemisches Institut, Universität Münster, Münster, Germany
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, P. R. China
| | | | - Malte Haring
- Organisch-Chemisches Institut, Universität Münster, Münster, Germany
| | - Hui Cao
- Organisch-Chemisches Institut, Universität Münster, Münster, Germany
| | | | - Armido Studer
- Organisch-Chemisches Institut, Universität Münster, Münster, Germany.
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6
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Lei J, Xu ZG. Reaction strategies for the meta-selective functionalization of pyridine through dearomatization. Mol Divers 2024:10.1007/s11030-024-10861-5. [PMID: 38647989 DOI: 10.1007/s11030-024-10861-5] [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: 02/19/2024] [Accepted: 03/25/2024] [Indexed: 04/25/2024]
Abstract
The pyridine moiety is a crucial structural component in various pharmaceuticals. While the direct ortho- and para-functionalization of pyridines is relatively straightforward, the meta-selective C-H functionalization remains a significant challenge. This review highlights dearomatization strategies as a key area of interest in expanding the application of meta-C-H functionalization of pyridines. Dearomatization enables the meta-functionalization through various catalytic methods that directly generate dearomatization products, and some products can be rearomatized back to pyridine derivatives. Furthermore, this article also covers the dearomatization of multiple positions of pyridine in the synthesis of polycyclic compounds. It offers a comprehensive overview of the latest advancements in dearomatization at different positions of pyridine, aiming to provide a valuable resource for researchers in this field. It also highlights the advantages and limitations of existing technologies, aiming to inform a broader audience about this important field and foster its future development.
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Affiliation(s)
- Jie Lei
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, IATTI, Chongqing University of Arts and Sciences, Chongqing, 402160, China
| | - Zhi-Gang Xu
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, IATTI, Chongqing University of Arts and Sciences, Chongqing, 402160, China.
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7
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Yu F, Wang W, Wang S. Copper-Catalyzed, Interrupted Remote Fluoromethylthiolation of Unactivated C(sp3)-H Bonds. Org Lett 2024; 26:2068-2072. [PMID: 38426710 DOI: 10.1021/acs.orglett.4c00336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
An efficient copper-catalyzed selective fluoromethylthiolation of an inert δ-C(sp3)-H bond in sulfonamides was reported. In the presence of a copper catalyst and PhSO2SRf, the radical generated through 1,5-hydrogen atom transfer (HAT) was sufficiently trapped by PhSO2SRf, instead of copper, which was prevalent in metal-catalyzed radical-relay processes, incorporating a fluoromethylthio group into molecules. The general substrate scope and mild conditions endowed the method with wide potential applications in pharmaceuticals and agrochemicals.
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Affiliation(s)
- Fan Yu
- Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, People's Republic of China
| | - Wengui Wang
- Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, People's Republic of China
| | - Shoufeng Wang
- Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, People's Republic of China
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8
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Jin R, Wang J, Li M, Tang T, Feng Y, Zhou S, Xie H, Feng H, Guo J, Fu R, Liu J, Tang Y, Shi Y, Guo H, Wang Y, Nie F, Li J. Discovery of a Novel Benzothiadiazine-Based Selective Aldose Reductase Inhibitor as Potential Therapy for Diabetic Peripheral Neuropathy. Diabetes 2024; 73:497-510. [PMID: 38127948 DOI: 10.2337/db23-0006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 12/13/2023] [Indexed: 12/23/2023]
Abstract
Aldose reductase 2 (ALR2), an activated enzyme in the polyol pathway by hyperglycemia, has long been recognized as one of the most promising targets for complications of diabetes, especially in diabetic peripheral neuropathy (DPN). However, many of the ALR2 inhibitors have shown serious side effects due to poor selectivity over aldehyde reductase (ALR1). Herein, we describe the discovery of a series of benzothiadiazine acetic acid derivatives as potent and selective inhibitors against ALR2 and evaluation of their anti-DPN activities in vivo. Compound 15c, carrying a carbonyl group at the 3-position of the thiadiazine ring, showed high potent inhibition against ALR2 (IC50 = 33.19 nmol/L) and ∼16,109-fold selectivity for ALR2 over ALR1. Cytotoxicity assays ensured the primary biosafety of 15c. Further pharmacokinetic assay in rats indicated that 15c had a good pharmacokinetic feature (t1/2 = 5.60 h, area under the plasma concentration time curve [AUC(0-t)] = 598.57 ± 216.5 μg/mL * h), which was superior to epalrestat (t1/2 = 2.23 h, AUC[0-t] = 20.43 ± 3.7 μg/mL * h). Finally, in a streptozotocin-induced diabetic rat model, 15c significantly increased the nerve conduction velocities of impaired sensory and motor nerves, achieved potent inhibition of d-sorbitol production in the sciatic nerves, and significantly increased the paw withdrawal mechanical threshold. By combining the above investigations, we propose that 15c might represent a promising lead compound for the discovery of an antidiabetic peripheral neuropathy drug. ARTICLE HIGHLIGHTS
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Affiliation(s)
- Ruyi Jin
- Shaanxi Key Lab Basic & New Herbal Medicament Research Center, College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, China
- Shenzhen Neptunus Pharmaceutical Research Institute Co., Ltd., Shenzhen, China
| | - Jin Wang
- Shenzhen Neptunus Pharmaceutical Research Institute Co., Ltd., Shenzhen, China
- Shenzhen Huahong Marine Biomedicine Co. Ltd., Shenzhen, China
| | - Mingyue Li
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Tianjin, China
| | - Tian Tang
- Shenzhen Neptunus Pharmaceutical Research Institute Co., Ltd., Shenzhen, China
- Cali Biosciences, Shenzhen, China
| | - Yidong Feng
- Shenzhen Neptunus Pharmaceutical Research Institute Co., Ltd., Shenzhen, China
| | - Sha Zhou
- State Key Laboratory of Elemento-Organic Chemistry, Institute of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering, College of Chemistry, Nankai University, Tianjin, China
| | - Honglei Xie
- School of Pharmacy, Shandong First Medical University and Shandong Academy of Medical Sciences, Yantai, China
| | - Haiyu Feng
- Shaanxi Key Lab Basic & New Herbal Medicament Research Center, College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, China
| | - Jianshuang Guo
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Tianjin, China
| | - Ruijia Fu
- Shaanxi Key Lab Basic & New Herbal Medicament Research Center, College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, China
| | - Jiping Liu
- Shaanxi Key Lab Basic & New Herbal Medicament Research Center, College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, China
| | - Yuping Tang
- Shaanxi Key Lab Basic & New Herbal Medicament Research Center, College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, China
| | - Yajun Shi
- Shaanxi Key Lab Basic & New Herbal Medicament Research Center, College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, China
| | - Hui Guo
- Shaanxi Key Lab Basic & New Herbal Medicament Research Center, College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, China
| | - Yuwei Wang
- Shaanxi Key Lab Basic & New Herbal Medicament Research Center, College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, China
| | - Fayi Nie
- Shaanxi Key Laboratory of Acupuncture and Medicine, Shaanxi University of Chinese Medicine, Xianyang, China
| | - Jing Li
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Tianjin, China
- State Key Laboratory of Elemento-Organic Chemistry, Institute of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering, College of Chemistry, Nankai University, Tianjin, China
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9
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Wang H, Greaney MF. Regiodivergent Arylation of Pyridines via Zincke Intermediates. Angew Chem Int Ed Engl 2024; 63:e202315418. [PMID: 37985419 DOI: 10.1002/anie.202315418] [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: 10/13/2023] [Revised: 11/16/2023] [Accepted: 11/20/2023] [Indexed: 11/22/2023]
Abstract
An arylation protocol for pyridines is described, via the ring-opened Zincke intermediate. Treatment of pyridines with triflic anhydride and a secondary amine produces an azahexatriene species, which undergoes regioselective Pd-catalyzed arylation at the putative C4 position. Recyclization then provides the pyridine products. Alternatively, metal-free arylation with a diaryliodonium salt is selective for the pyridine meta-position, affording a regiodivergent approach to pyridine biaryls from a common intermediate.
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Affiliation(s)
- Haiwen Wang
- School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Michael F Greaney
- School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
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10
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Wang J, Lu XX, Yang RP, Zhang BB, Xiang ZH, Li JC, Liu L, Chao S, Shang X. N-Trifluoromethylselenophthalimide, an Electrophilic Trifluoromethylselenolation Reagent and Its Application for the Synthesis of 4-Trifluoromethylselenolated Isoxazoles. Org Lett 2023; 25:8489-8494. [PMID: 37966853 DOI: 10.1021/acs.orglett.3c03446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
A new electrophilic trifluoromethylselenolation reagent, N-trifluoromethylselenophthalimide (Phth-SeCF3), was developed. A strategy for the synthesis of 4-trifluoromethylselenolated isoxazoles through electrophilic trifluoromethylselenolation cyclization has been established by using Phth-SeCF3 as an electrophilic reagent. Moreover, this protocol has the features of broad substrate scope, good functional group tolerance, and high yields.
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Affiliation(s)
- Jia Wang
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Xiao-Xiao Lu
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Run-Ping Yang
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Bing-Bing Zhang
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Zhi-Hao Xiang
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Jia-Cheng Li
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Lixia Liu
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Shujun Chao
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Xuefang Shang
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan 453003, China
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11
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Cao H, Cheng Q, Studer A. meta-Selective C-H Functionalization of Pyridines. Angew Chem Int Ed Engl 2023; 62:e202302941. [PMID: 37013613 DOI: 10.1002/anie.202302941] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/01/2023] [Accepted: 04/03/2023] [Indexed: 04/05/2023]
Abstract
The pyridine moiety is an important core structure for a variety of drugs, agrochemicals, catalysts, and functional materials. Direct functionalization of C-H bonds in pyridines is a straightforward approach to access valuable substituted pyridines. Compared to the direct ortho- and para-functionalization, meta-selective pyridine C-H functionalization is far more challenging due to the inherent electronic properties of the pyridine entity. This review summarizes currently available methods for pyridine meta-C-H functionalization using a directing group, non-directed metalation, and temporary dearomatization strategies. Recent advances in ligand control and temporary dearomatization are highlighted. We analyze the advantages as well as limitations of current techniques and hope to inspire further developments in this important area.
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Affiliation(s)
- Hui Cao
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Qiang Cheng
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
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12
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Kuninobu Y. Regioselective C-H Trifluoromethylation and Its Related Reactions of (Hetero)aromatic Compounds. CHEM REC 2023; 23:e202300003. [PMID: 36899485 DOI: 10.1002/tcr.202300003] [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: 01/04/2023] [Revised: 02/04/2023] [Indexed: 03/12/2023]
Abstract
Fluorinated functional groups, including trifluoromethyl group, play important roles in the development of drugs, agrochemicals, and organic functional materials. Therefore, the development of highly effective and practical reactions to introduce fluorinated functional groups into (hetero)aromatic compounds is highly desirable. We have achieved several regioselective C-H trifluoromethylation and related reactions by electrophilic and nucleophilic activation of six-membered heteroaromatic compounds and steric protection of aromatic compounds. These reactions proceed in good to excellent yields, even on a gram scale, with high functional group tolerance, and are applicable to the regioselective trifluoromethylation of drug molecules. In this personal account, the background of the introduction reactions of fluorinated functional groups, our reaction designs to achieve regioselective C-H trifluoromethylation and the related reactions of (hetero)aromatic compounds are explained.
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Affiliation(s)
- Yoichiro Kuninobu
- Institute for Materials Chemistry and Engineering, Interdisciplinary Engineering Sciences, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasugakoen, Kasuga-shi, Fukuoka 816-8580, Japan
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13
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Tian JJ, Li RR, Tian GX, Wang XC. Enantioselective C3-Allylation of Pyridines via Tandem Borane and Palladium Catalysis. Angew Chem Int Ed Engl 2023; 62:e202307697. [PMID: 37395559 DOI: 10.1002/anie.202307697] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 06/28/2023] [Accepted: 07/03/2023] [Indexed: 07/04/2023]
Abstract
Herein, we report a one-pot method for enantioselective C-H allylation of pyridines at C3 via tandem borane and palladium catalysis. This method involves borane-catalyzed pyridine hydroboration to generate dihydropyridines, then palladium-catalyzed enantioselective allylation of the dihydropyridines with allylic esters, and finally air oxidation of the allylated dihydropyridines to afford the products. This method enables the introduction of an allylic group at C3 with excellent regio- and enantioselectivities.
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Affiliation(s)
- Jun-Jie Tian
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Rui-Rui Li
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Gui-Xiu Tian
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Xiao-Chen Wang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
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14
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Wei J, Xing Y, Ye X, Nguyen B, Wojtas L, Hong X, Shi X. Gold-Catalyzed Amine Cascade Addition to Diyne-Ene: Enantioselective Synthesis of 1,2-Dihydropyridines. Angew Chem Int Ed Engl 2023; 62:e202305409. [PMID: 37167070 PMCID: PMC10524696 DOI: 10.1002/anie.202305409] [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: 04/17/2023] [Revised: 05/10/2023] [Accepted: 05/11/2023] [Indexed: 05/13/2023]
Abstract
With the well-documented chemical and biological applications, piperidine and pyridine are among the most important N-heterocycles, and a new synthetic strategy, especially one with an alternative bond-forming design, is of general interest. Using the gold-catalyzed intermolecular condensation of amine and diyne-ene, we report herein the first example of enantioselective 1,2-dihydropyridine synthesis through a formal [3+2+1] fashion (up to 95 % yield, up to 99 % e.e.).
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Affiliation(s)
- Jingwen Wei
- Department of Chemistry, University of South Florida, FL 33620, Tampa, USA
| | - Yangyang Xing
- Center of Chemistry for Frontier Technologies, Department of Chemistry, Zhejiang University, 310027, Hangzhou, China
| | - Xiaohan Ye
- Department of Chemistry, University of South Florida, FL 33620, Tampa, USA
| | - Bao Nguyen
- Department of Chemistry, University of South Florida, FL 33620, Tampa, USA
| | - Lukasz Wojtas
- Department of Chemistry, University of South Florida, FL 33620, Tampa, USA
| | - Xin Hong
- Center of Chemistry for Frontier Technologies, Department of Chemistry, Zhejiang University, 310027, Hangzhou, China
| | - Xiaodong Shi
- Department of Chemistry, University of South Florida, FL 33620, Tampa, USA
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15
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Abstract
Azines, such as pyridines, quinolines, pyrimidines, and pyridazines, are widespread components of pharmaceuticals. Their occurrence derives from a suite of physiochemical properties that match key criteria in drug design and is tunable by varying their substituents. Developments in synthetic chemistry, therefore, directly impact these efforts, and methods that can install various groups from azine C-H bonds are particularly valuable. Furthermore, there is a growing interest in late-stage functionalization (LSF) reactions that focus on advanced candidate compounds that are often complex structures with multiple heterocycles, functional groups, and reactive sites. Because of factors such as their electron-deficient nature and the effects of the Lewis basic N atom, azine C-H functionalization reactions are often distinct from their arene counterparts, and the application of these reactions in LSF contexts is difficult. However, there have been many significant advances in azine LSF reactions, and this review will describe this progress, much of which has occurred over the past decade. It is possible to categorize these reactions as radical addition processes, metal-catalyzed C-H activation reactions, and transformations occurring via dearomatized intermediates. Substantial variation in reaction design within each category indicates both the rich reactivity of these heterocycles and the creativity of the approaches involved.
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Affiliation(s)
- Celena M Josephitis
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Hillary M H Nguyen
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Andrew McNally
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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16
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Shen Q. A Toolbox of Reagents for Trifluoromethylthiolation: From Serendipitous Findings to Rational Design. J Org Chem 2023; 88:3359-3371. [PMID: 36795864 DOI: 10.1021/acs.joc.2c02777] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Two types of electrophilic trifluoromethylthiolating reagents were developed in the past 10 years in our laboratory. The development of the first type of reagent, trifluoromethanesulfenate I, which is highly reactive toward a variety of nucleophiles, was based on an unexpected discovery in the initial design for the development of an electrophilic trifluoromethylthiolating reagent with a hypervalent iodine skeleton. A structure-activity study disclosed that α-cumyl trifluoromethanesulfenate (reagent II) without the iodo substituent is equally effective. Subsequent derivatization let us develop an α-cumyl bromodifluoromethanesulfenate III that could be used for the preparation of [18F]ArSCF3. To remediate the low reactivity of the type I electrophilic trifluoromethylthiolating reagent for Friedel-Crafts trifluoromethylthiolation of electron-rich (hetero)arenes, we designed and prepared N-trifluoromethylthiosaccharin IV, which exhibits broad reactivity toward various nucleophiles, including electron-rich arenes. A comparison of the structure of N-trifluoromethylthiosaccharin IV with that of N-trifluoromethylthiophthalimide showed that the replacement of one carbonyl group in N-trifluoromethylthiophthalimide with a sulfonyl group made N-trifluoromethylthiosaccharin IV much more electrophilic. Thus, the replacement of both carbonyls with two sulfonyl groups would further increase the electrophilicity. Such a rationale prompted us to design and develop the current most electrophilic trifluoromethylthiolating reagent, N-trifluoromethylthiodibenzenesulfonimide V, and its reactivity was much higher than that of N-trifluoromethylthiosaccharin IV. We further developed an optically pure electrophilic trifluoromethylthiolating reagent, (1S)-(-)-N-trifluoromethylthio-2,10-camphorsultam VI, for the preparation of optically active trifluoromethylthio-substituted carbon stereogenic centers. Reagents I-VI now constitute a powerful toolbox for the introduction of the trifluoromethylthio group into the target molecules.
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Affiliation(s)
- Qilong Shen
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
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17
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Chakraborty S, Biju AT. Directing Group-Free Regioselective meta-C-H Functionalization of Pyridines. Angew Chem Int Ed Engl 2023; 62:e202300049. [PMID: 36829265 DOI: 10.1002/anie.202300049] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 02/22/2023] [Accepted: 02/24/2023] [Indexed: 02/26/2023]
Abstract
The pyridine core is among the most common motifs found in pharmaceuticals and agrochemicals. Consequently, the C-H functionalization of pyridine is a prized reaction, as it can help access a broad spectrum of valuable chemicals. However, the intrinsic electronic properties of pyridines hinder their meta-C-H functionalization, requiring drastic conditions affecting functional group compatibility. A synthetic manoeuvre to overcome this challenge involves the temporary conversion of pyridines into electron-rich intermediates and subsequent regioselective electrophilic functionalization. This was recently accomplished by a ring-opening ring-closing sequence via Zincke imine intermediates by McNally and co-workers, and a dearomatization-rearomatization sequence via oxazino-pyridine intermediates by the Studer group. The mildness and simplicity of these protocols enable them to work with complex molecular setups for synthesizing natural products and bioactive molecules.
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Affiliation(s)
- Sukriyo Chakraborty
- Department of Organic Chemistry, Indian Institute of Science Bangalore, C.V. Raman Avenue, Bengaluru, 560 012, India
| | - Akkattu T Biju
- Department of Organic Chemistry, Indian Institute of Science Bangalore, C.V. Raman Avenue, Bengaluru, 560 012, India
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18
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Zhang M, Zhou Q, Luo H, Tang ZL, Xu X, Wang XC. C3-Cyanation of Pyridines: Constraints on Electrophiles and Determinants of Regioselectivity. Angew Chem Int Ed Engl 2023; 62:e202216894. [PMID: 36517651 DOI: 10.1002/anie.202216894] [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: 11/17/2022] [Revised: 12/14/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Methods for C-H cyanation of pyridines are rare. Here, we report a method for C3-selective cyanation of pyridines by a tandem process with the reaction of an in situ generated dihydropyridine with a cyano electrophile as the key step. The method is suitable for late-stage functionalization of pyridine drugs. The low reduction potential of the electrophile and effective transfer of the nitrile group were found to be essential for the success of this method. We studied the reaction mechanism in detail by means of control experiments and theoretical calculations and found that a combination of electronic and steric factors determined the regioselectivity of reactions involving C2-substituted pyridines.
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Affiliation(s)
- Ming Zhang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Qingyang Zhou
- Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Heng Luo
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Zi-Lu Tang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Xiufang Xu
- Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
| | - Xiao-Chen Wang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Haihe Laboratory of Sustainable Chemical Transformations, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, 94 Weijin Road, Tianjin, 300071, China
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19
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Hu C, Vo C, Merchant RR, Chen SJ, Hughes JME, Peters BK, Qin T. Uncanonical Semireduction of Quinolines and Isoquinolines via Regioselective HAT-Promoted Hydrosilylation. J Am Chem Soc 2023; 145:25-31. [PMID: 36548026 PMCID: PMC9930105 DOI: 10.1021/jacs.2c11664] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Heterocycles are the backbone of modern medical chemistry and drug development. The derivatization of "an olefin" inside aromatic rings represents an ideal approach to access functionalized saturated heterocycles from abundant aromatic building blocks. Here, we report an operationally simple, efficient, and practical method to selectively access hydrosilylated and reduced N-heterocycles from bicyclic aromatics via a key diradical intermediate. This approach is expected to facilitate complex heterocycle functionalizations that enable access to novel medicinally relevant scaffolds.
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Affiliation(s)
- Chao Hu
- Department of Biochemistry, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
| | - Cuong Vo
- Department of Biochemistry, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
| | - Rohan R. Merchant
- Department of Discovery Chemistry, Merck & Co., Inc., South San Francisco, California 94080, United States
| | - Si-Jie Chen
- Department of Discovery Chemistry, Merck & Co., Inc., South San Francisco, California 94080, United States
| | - Jonathan M. E. Hughes
- Department of Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Byron K. Peters
- Department of Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Tian Qin
- Department of Biochemistry, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
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20
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Joo JM. Adding functions to pyridines. Science 2022; 378:710-711. [DOI: 10.1126/science.ade5501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Chemical reactions break a pyridine ring to allow its modification
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Affiliation(s)
- Jung Min Joo
- Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan 46241, South Korea
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21
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Cao H, Cheng Q, Studer A. Radical and ionic
meta
-C–H functionalization of pyridines, quinolines, and isoquinolines. Science 2022; 378:779-785. [DOI: 10.1126/science.ade6029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Carbon-hydrogen (C−H) functionalization of pyridines is a powerful tool for the rapid construction and derivatization of many agrochemicals, pharmaceuticals, and materials. Because of the inherent electronic properties of pyridines, selective
meta
-C−H functionalization is challenging. Here, we present a protocol for highly regioselective
meta
-C−H trifluoromethylation, perfluoroalkylation, chlorination, bromination, iodination, nitration, sulfanylation, and selenylation of pyridines through a redox-neutral dearomatization-rearomatization process. The introduced dearomative activation mode provides a diversification platform for meta-selective reactions on pyridines and other azaarenes through radical as well as ionic pathways. The broad scope and high selectivity of these catalyst-free reactions render these processes applicable for late-stage functionalization of drugs.
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Affiliation(s)
- Hui Cao
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Münster, Germany
| | - Qiang Cheng
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Münster, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Münster, Germany
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22
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Boyle BT, Levy JN, de Lescure L, Paton RS, McNally A. Halogenation of the 3-position of pyridines through Zincke imine intermediates. Science 2022; 378:773-779. [PMID: 36395214 PMCID: PMC10631470 DOI: 10.1126/science.add8980] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
Pyridine halogenation reactions are crucial for obtaining the vast array of derivatives required for drug and agrochemical development. However, despite more than a century of synthetic endeavors, halogenation processes that selectively functionalize the carbon-hydrogen bond in the 3-position of a broad range of pyridine precursors remain largely elusive. We report a reaction sequence of pyridyl ring opening, halogenation, and ring closing whereby the acyclic Zincke imine intermediates undergo highly regioselective halogenation reactions under mild conditions. Experimental and computational mechanistic studies indicate that the nature of the halogen electrophile can modify the selectivity-determining step. Using this method, we produced a diverse set of 3-halopyridines and demonstrated late-stage halogenation of complex pharmaceuticals and agrochemicals.
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Affiliation(s)
| | | | - Louis de Lescure
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
| | - Robert S. Paton
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
| | - Andrew McNally
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
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23
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Muta R, Torigoe T, Kuninobu Y. 3-Position-Selective C–H Trifluoromethylation of Pyridine Rings Based on Nucleophilic Activation. Org Lett 2022; 24:8218-8222. [DOI: 10.1021/acs.orglett.2c03327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Ryuhei Muta
- Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasugakoen, Kasuga-shi, Fukuoka 816-8580, Japan
| | - Takeru Torigoe
- Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasugakoen, Kasuga-shi, Fukuoka 816-8580, Japan
- Department of Interdisciplinary Engineering Sciences, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasugakoen, Kasuga-shi, Fukuoka 816-8580, Japan
| | - Yoichiro Kuninobu
- Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasugakoen, Kasuga-shi, Fukuoka 816-8580, Japan
- Department of Interdisciplinary Engineering Sciences, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasugakoen, Kasuga-shi, Fukuoka 816-8580, Japan
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24
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Chen F, Qing F. Selective Trifluoromethiolation and Difluoromethiolation of Pyridines at C(3) Position. CHINESE J ORG CHEM 2022. [DOI: 10.6023/cjoc202200055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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