1
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He Y, Chen J, Jiang Y, Fang X, Liu J, Yan JL. N-Heterocyclic Carbene Catalyzed Reactions Involving Acetylenic Breslow and/or Acylazolium as Key Intermediates. CHEM REC 2024; 24:e202400165. [PMID: 39558761 DOI: 10.1002/tcr.202400165] [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: 08/20/2024] [Revised: 10/14/2024] [Indexed: 11/20/2024]
Abstract
N-heterocyclic carbene (NHC) organocatalysis has been developed as a powerful tool in modern synthetic chemistry. NHC catalytic activation of ynals and alkynoic acid derivatives provided versatile reactions that involve acetylenic Breslow and/or acylazolium as key intermediates, and diverse transformations have been established for access to molecules with unique skeletons in efficient fashions. Herein we summarize the recent achievements in NHC-catalyzed reactions involving acetylenic Breslow and/or acylazolium intermediates. Different reactions belonging to three catalytic modes, including (1) conjugate additions to acetylenic Breslow derived α,β-unsaturated acylazolium intermediates, (2) β-umpolung of ynals via acetylenic Breslow intermediates, and (3) conjugate additions to acetylenic acylazolium intermediates, are emphasized with examples and plausible mechanisms cited to guide a better understanding.
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Affiliation(s)
- Yujie He
- School of Pharmacy and Food Engineering, Wuyi University, Jiangmen, 529020, China
| | - Jintao Chen
- School of Pharmacy and Food Engineering, Wuyi University, Jiangmen, 529020, China
| | - Yu Jiang
- School of Pharmacy and Food Engineering, Wuyi University, Jiangmen, 529020, China
| | - Xiaoyu Fang
- School of Pharmacy and Food Engineering, Wuyi University, Jiangmen, 529020, China
| | - Junyang Liu
- School of Pharmacy and Food Engineering, Wuyi University, Jiangmen, 529020, China
| | - Jia-Lei Yan
- School of Pharmacy and Food Engineering, Wuyi University, Jiangmen, 529020, China
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2
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Miao Y, Qi J, Li Y, Pan A, Duan XY. N-Heterocyclic Carbene-Catalyzed [3 + 3] Annulation of Enals with Aminonaphthoquinones for the Synthesis of Functionalized Aza-anthraquinones. J Org Chem 2024; 89:16433-16443. [PMID: 39494963 DOI: 10.1021/acs.joc.4c01655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2024]
Abstract
Rapid construction of functionalized aza-anthraquinones has been successfully developed via NHC-catalyzed formal [3 + 3] annulation of 2-aminoquinones with enals. This reaction features several advantages, such as readily available starting materials, mild reaction conditions, and flexible product transformations. The study on the atroposelective version of this strategy was also carried out, and several C-N axial chiral aza-anthraquinones were synthesized in moderate yields with moderate to good enantioselectivities.
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Affiliation(s)
- Yuehua Miao
- College of Chemistry and Materials Science, Chemical Biology Key Laboratory of Hebei Province, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Hebei University, Baoding 071002, China
| | - Jing Qi
- College of Chemistry and Materials Science, Chemical Biology Key Laboratory of Hebei Province, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Hebei University, Baoding 071002, China
- State Key Laboratory of New Pharmaceutical Preparations and Excipients, College of Chemistry and Materials Science, Hebei University, Baoding 071002, China
| | - Yanting Li
- College of Chemistry and Materials Science, Chemical Biology Key Laboratory of Hebei Province, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Hebei University, Baoding 071002, China
| | - Ao Pan
- College of Chemistry and Materials Science, Chemical Biology Key Laboratory of Hebei Province, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Hebei University, Baoding 071002, China
| | - Xiao-Yong Duan
- College of Chemistry and Materials Science, Chemical Biology Key Laboratory of Hebei Province, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Hebei University, Baoding 071002, China
- State Key Laboratory of New Pharmaceutical Preparations and Excipients, College of Chemistry and Materials Science, Hebei University, Baoding 071002, China
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3
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Sarkar S, Das S, Gandhi S. Catalytic Synthesis of 1 H-Benzoxazolo[3,2- a]pyridin-1-ones via Formal [3 + 3] Annulations of NHC-Generated Alkynyl Acylazoliums with Benzoxazolyl Acetates and Their Photophysical Studies. J Org Chem 2024; 89:15559-15567. [PMID: 39431487 DOI: 10.1021/acs.joc.4c01616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2024]
Abstract
We disclose the synthesis of a tricyclic fused N-heterocycle via the NHC-catalyzed annulation of either a ynal or an alkynyl ester with readily accessible benzoxazolyl acetate. While the annulation with ynals requires an oxidant, the reaction with alkynyl esters proceeds via the direct generation of alkynyl acylazolium intermediates with an NHC. With the dearth of catalytic processes to access these 1H-benzoxazolo[3,2-a]pyridin-1-ones from simple starting materials, this method is especially important. The photophysical properties of the products have also been evaluated.
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Affiliation(s)
- Sibasis Sarkar
- Department of Chemical Sciences, Indian Institute of Science Education and Research Berhampur, Berhampur, Odisha 760010, India
| | - Suravi Das
- Department of Chemical Sciences, Indian Institute of Science Education and Research Berhampur, Berhampur, Odisha 760010, India
| | - Shikha Gandhi
- Department of Chemical Sciences, Indian Institute of Science Education and Research Berhampur, Berhampur, Odisha 760010, India
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4
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Li L, Li C, Zhang S, Wang X, Fu P, Wang Y. Catalytic Asymmetric Synthesis of 3,4'-Piperidinoyl Spirooxindoles via [3 + 3] Annulation of 3-Aminobenzofurans and Isatin-Derived Enals. J Org Chem 2024; 89:5170-5180. [PMID: 38545893 DOI: 10.1021/acs.joc.4c00046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
A chiral NHC-catalyzed [3 + 3] cycloaddition reaction of 3-aminobenzofurans with isatin-derived enals has been documented, furnishing 3,4'-piperidinoyl spirooxindoles bearing a quaternary stereocenter with good yields and excellent enantioselectivities. Further gram-scale preparation and synthetic transformation of the cycloadducts to δ-amino acid derivative demonstrated good practicality and applicability of this reaction.
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Affiliation(s)
- Lesong Li
- Molecular Synthesis Center & Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Congyang Li
- Molecular Synthesis Center & Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Shuting Zhang
- Molecular Synthesis Center & Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Xuerui Wang
- Molecular Synthesis Center & Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Peng Fu
- Molecular Synthesis Center & Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
- Laboratory for Marine Drugs and Bioproducts, Laoshan Laboratory, Qingdao 266237, China
| | - Yang Wang
- Molecular Synthesis Center & Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
- Laboratory for Marine Drugs and Bioproducts, Laoshan Laboratory, Qingdao 266237, China
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5
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Wang Y, Huang X, Ji H, Zhou H, Gao H, Xu J. Bifunctional Thiourea-Catalyzed Enantioselective Aza-Friedel-Crafts Reaction of 3-Aminobenzofurans with Isatin-Derived Ketimines. J Org Chem 2023; 88:15486-15493. [PMID: 37867301 DOI: 10.1021/acs.joc.3c01741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2023]
Abstract
A quinine-derived thiourea-promoted enantioselective aza-Friedel-Crafts reaction of 3-aminobenzofurans with isatin-derived ketimines is developed, providing a variety of 3-benzofuran-3-amino-2-oxindoles bearing a quaternary stereocenter with good to excellent yields (72-95%) and moderate to excellent enantioselectivities (48-97%). The synthetic potential of this concise and efficient protocol is revealed by gram-scale preparation and further transformation of the adduct to an optically pure spirocyclic oxindole.
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Affiliation(s)
- Yangyang Wang
- Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
| | - Xiaoming Huang
- Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
| | - Haojie Ji
- Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
| | - Hongwei Zhou
- College of Biological, Chemical Science and Engineering, Jiaxing University, 118 Jiahang Road, Jiaxing 314001, P. R. China
| | - Hongjie Gao
- Pharmaron (Ningbo) Technology Development Co., Ltd., No. 800 Bin-Hai fourth Road, Hangzhou Bay New Zone, Ningbo 315336, P. R. China
| | - Jianfeng Xu
- Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
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Gao J, Zhang S, Du D. Alkynyl Acylazolium: a Versatile 1,3-Bielectrophilic 3C-Synthon in NHC-Organocatalysis. CHEM REC 2023:e202300046. [PMID: 36942970 DOI: 10.1002/tcr.202300046] [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: 02/02/2023] [Revised: 03/03/2023] [Indexed: 03/23/2023]
Abstract
N-Heterocyclic carbene (NHC) organocatalysis has emerged as a powerful tool in the field of modern organic synthesis especially in the asymmetric construction of various cyclic skeletons. As an emerging NHC-bound 1,3-bielectrophilic intermediate, alkynyl acylazolium has drawn substantial attention in recent years, and has been used as a versatile 3C-synthon in synthesizing valuable organic molecules since its discovery. In this review, focused on the different pathways for the formation of alkynyl acylazoliums from different precursors like alkynoic esters, alkynoic acids and ynals, the recent advances in the transformations and applications of alkynyl acylazoliums pioneered or developed over the last decade under NHC-catalysis were summarized comprehensively. At the same time, the outlook for further investigation and exploration of novel reaction modes for alkynyl acylazoliums in the future was also discussed.
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Affiliation(s)
- Jian Gao
- Department of Chemistry, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, P. R. China
| | - Simiao Zhang
- Department of Chemistry, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, P. R. China
| | - Ding Du
- Department of Chemistry, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, P. R. China
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Sun M, Gui J, Zhong R, Wu H, Liu S, Li J, Yang J, Wang Z. TfOH-catalyzed direct Michael addition and cascade cyclization reactions of unactivated ketones: A divergent route to functionalized benzofurans and benzofuro[3,2-b]pyridines. Tetrahedron 2023. [DOI: 10.1016/j.tet.2023.133394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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8
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Liang Z, Li J, Wang L, Wei Z, Huang J, Wang X, Du D. Construction of Functionalized 2 H-Pyran-2-ones via N-Heterocyclic Carbene-Catalyzed [3 + 3] Annulation of Alkynyl Esters with Enolizable Ketones. J Org Chem 2023; 88:1836-1843. [PMID: 36696583 DOI: 10.1021/acs.joc.2c02392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A new synthesis of functionalized 2H-pyran-2-ones has been developed through N-heterocyclic carbene-catalyzed formal [3 + 3] annulation of alkynyl esters with enolizable ketones. The key to the success of this protocol relies on the use of an NHC instead of a tertiary amine as the catalyst. This protocol also features a broad substrate scope and mild metal-free conditions, offering simple and rapid access to the target molecules in a highly regioselective manner.
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Affiliation(s)
- Zheng Liang
- State Key Laboratory of Natural Medicines, School of Science, China Pharmaceutical University, Nanjing, 210009, People's Republic of China
| | - Jibin Li
- State Key Laboratory of Natural Medicines, School of Science, China Pharmaceutical University, Nanjing, 210009, People's Republic of China
| | - Lei Wang
- State Key Laboratory of Natural Medicines, School of Science, China Pharmaceutical University, Nanjing, 210009, People's Republic of China
| | - Zexuan Wei
- State Key Laboratory of Natural Medicines, School of Science, China Pharmaceutical University, Nanjing, 210009, People's Republic of China
| | - Jiahui Huang
- State Key Laboratory of Natural Medicines, School of Science, China Pharmaceutical University, Nanjing, 210009, People's Republic of China
| | - Xinrui Wang
- State Key Laboratory of Natural Medicines, School of Science, China Pharmaceutical University, Nanjing, 210009, People's Republic of China
| | - Ding Du
- State Key Laboratory of Natural Medicines, School of Science, China Pharmaceutical University, Nanjing, 210009, People's Republic of China
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Soto J. Photochemistry of 1-Phenyl-1-diazopropane and Its Diazirine Isomer: A CASSCF and MS-CASPT2 Study. J Phys Chem A 2022; 126:8372-8379. [PMID: 36335481 PMCID: PMC9677432 DOI: 10.1021/acs.jpca.2c04816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 10/10/2022] [Indexed: 11/07/2022]
Abstract
In this work, we studied the wavelength (520 or 350 nm) dependence of the photochemical decomposition of 1-phenyl-1-diazopropane (PDP) and 1-phenyl-1-propyl diazirine (PED) by means of high-level ab initio quantum chemical calculations (CASSCF and MS-CASPT2) to obtain qualitative and quantitative results. It is found that the photochemistry of PDP is governed by nonradiative deactivation processes that can involve one or two S1/S0 conical intersections (CI1 and CI2) depending on the wavelength of the radiation; CI2 is only accessible at the shortest wavelength. It is demonstrated that the main intermediate of the photochemistry of the titled compounds is 1-ethyl-1-phenyl carbene (EPC). Upon irradiation of PDP with the 520 nm light, the carbene is always generated in its ground state as closed-shell singlet carbene. In contrast, the 350 nm radiation can directly decompose PDP into S1 carbene (open shell) and N2 when the conical intersection CI2 is avoided. Once the carbene is formed in the S1 state, it can experience excited state intramolecular proton transfer along a seam of crossing (ESIPT-SC) of the S1 and S0 states to yield the alkene derivative; that is, the proton transfer reaction takes places on a degenerate potential energy surface where the two electronic states have equal energy. In addition, it is found that EPC absorbs at 350 nm (double excitations); therefore, there is another possible route that can induce as well a slightly different photochemistry in changing the wavelength of the radiation because the shortest wavelength (when it is intense enough) decreases the amount of available EPC or generates a highly vibrationally excited state of the carbene; that is, after 350 nm excitation, the carbene intermediate can deactivate via radiation emission or can decay through a cascade of conical intersections to its first excited state (S1), where ESIPT-SC is operative again.
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Affiliation(s)
- Juan Soto
- Department of Physical Chemistry,
Faculty of Science, University of Málaga, 29071 Málaga, Spain
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10
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Dong Z, Jiang C, Zhao C. A Review on Generation and Reactivity of the N-Heterocyclic Carbene-Bound Alkynyl Acyl Azolium Intermediates. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27227990. [PMID: 36432089 PMCID: PMC9696695 DOI: 10.3390/molecules27227990] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/14/2022] [Accepted: 11/14/2022] [Indexed: 11/19/2022]
Abstract
N-heterocyclic carbene (NHC) has been widely used as an organocatalyst for both umpolung and non-umpolung chemistry. Previous works mainly focus on species including Breslow intermediate, azolium enolate intermediate, homoenolate intermediate, alkenyl acyl azolium intermediate, etc. Notably, the NHC-bound alkynyl acyl azolium has emerged as an effective intermediate to access functionalized cyclic molecular skeleton until very recently. In this review, we summarized the generation and reactivity of the NHC-bound alkynyl acyl azolium intermediates, which covers the efforts and advances in the synthesis of achiral and axially chiral cyclic scaffolds via the NHC-bound alkynyl acyl azolium intermediates. In particular, the mechanism related to this intermediate is discussed in detail.
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11
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Barik S, Das RC, Balanna K, Biju AT. Kinetic Resolution Approach to the Synthesis of C-N Axially Chiral N-Aryl Aminomaleimides via NHC-Catalyzed [3 + 3] Annulation. Org Lett 2022; 24:5456-5461. [PMID: 35856856 DOI: 10.1021/acs.orglett.2c02185] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chiral NHC-catalyzed kinetic resolution of N-aryl aminomaleimides allowing the synthesis of C-N axially chiral N-aryl aminomaleimides via remote chirality control is presented. The catalytically generated α,β-unsaturated acylazoliums from 2-bromoenals underwent selective [3 + 3] annulation with one of the enantiomers of maleimide to furnish fused-dihydropyridinone (bearing axial/central chirality, up to 6:1 dr, >99:1 er) leaving the enantioenriched opposite enantiomer (up to >99:1 er). Studies on C-N bond rotation barrier and dependence on temperature are also provided.
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Affiliation(s)
- Soumen Barik
- Department of Organic Chemistry, Indian Institute of Science, Bangalore-560012, India
| | - Rohan Chandra Das
- Department of Organic Chemistry, Indian Institute of Science, Bangalore-560012, India
| | - Kuruva Balanna
- Department of Organic Chemistry, Indian Institute of Science, Bangalore-560012, India
| | - Akkattu T Biju
- Department of Organic Chemistry, Indian Institute of Science, Bangalore-560012, India
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Lu F, Chen Y, Song X, Yu C, Li T, Zhang K, Yao C. NHC-Catalyzed [2 + 4] Annulation of Alkynyl Ester with Chalcone. J Org Chem 2022; 87:6902-6909. [PMID: 35486449 DOI: 10.1021/acs.joc.2c00022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An NHC-catalyzed [2 + 4] cyclization of alkynyl ester with α,β-unsaturated ketone to form a pyran scaffold was developed successfully. The cheap and easily available starting materials, mild reaction conditions, moderate to excellent yields, and high atom economy make this strategy attractive for the syntheses of highly substituted 4H-pyran derivatives.
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Affiliation(s)
- Fangfang Lu
- Jiangsu Key Lab of Green Synthetic Chemistry for Functional Materials, School of Chemistry & Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P. R. China
| | - Yangxu Chen
- Jiangsu Key Lab of Green Synthetic Chemistry for Functional Materials, School of Chemistry & Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P. R. China
| | - Xue Song
- Jiangsu Key Lab of Green Synthetic Chemistry for Functional Materials, School of Chemistry & Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P. R. China
| | - Chenxia Yu
- Jiangsu Key Lab of Green Synthetic Chemistry for Functional Materials, School of Chemistry & Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P. R. China
| | - Tuanjie Li
- Jiangsu Key Lab of Green Synthetic Chemistry for Functional Materials, School of Chemistry & Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P. R. China
| | - Kai Zhang
- Jiangsu Key Lab of Green Synthetic Chemistry for Functional Materials, School of Chemistry & Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P. R. China
| | - Changsheng Yao
- Jiangsu Key Lab of Green Synthetic Chemistry for Functional Materials, School of Chemistry & Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P. R. China
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