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Xu G, Bai X, Dang Q. Aromatic Heterocycles as Productive Dienophiles in the Inverse Electron-Demand Diels-Alder Reactions of 1,3,5-Triazines. Acc Chem Res 2020; 53:773-781. [PMID: 32227911 DOI: 10.1021/acs.accounts.9b00604] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Heterocycles are often found as the structural nucleus in natural products and biological active compounds. Consequently, research toward the discovery and development of novel and efficient synthetic methodologies is of constant interest to organic chemists. Diels-Alder reactions are powerful at forming multiple bonds simultaneously, often with stereoselectivity, and thus are one of the most widely used synthetic methodologies in organic syntheses. Inverse electron-demand Diels-Alder (IEDDA) reactions, a subclass of Diels-Alder reactions, have been developed for the efficient synthesis of various heterocycles, with 1,3,5-triazines used as azadienes. The initial 1,3,5-triazine IEDDA reactions mostly included nonaromatic, electron-rich species such as vinyl ethers, enamines, ynamines, and amidines as dienophiles, producing in high yields pyrimidine derivatives with excellent regioselectivity. We hypothesized that some electron-rich aromatic heterocycles could be studied as potential dienophiles for 1,3,5-triazine IEDDA reactions; 5-aminopyrazoles proved to be productive dienophiles leading to high yields of pyrazolopyrimidines. Subsequently, many studies were reported to investigate the mechanism and scope of this new type of IEDDA reaction. Mechanistically, this new type of IEDDA reaction is quite interesting since it entails two aromatic compounds proceeding through a perceived high energy nonaromatic transition state, leading to a new aromatic compound, a counterintuitive process. Both theoretical and experimental studies provide key insights to this reaction mechanism, with learnings from these studies possibly stimulating unconventional thinking in other areas. Theoretical calculations of these cascade reactions of amino-substituted heterocycles with 1,3,5-triazines indicate that the reactions occur in a stepwise fashion via a highly polar zwitterionic intermediate; elimination of ammonia from IEDDA adducts and subsequent retro Diels-Alder reaction drive the reaction toward the fully aromatized IEDDA products. This amino substituent is critical in determining the regioselectivity and driving the cascade reactions to completion. With regard to reaction scope, many amino-heterocycles such as pyrroles, imidazoles, furans, thiophenes, and indoles all proved to be productive dienophiles for this new IEDDA reaction, leading to various fused-pyrimidines in a single step with moderate to high yields and high regioselectivity. Application of this new IEDDA reaction with 1,3,5-triazines was reported to lead to interesting heterocyclic compounds such as nucleoside natural product nebularine and analogues, as well as fluorine-containing fused pyrimidines with potential for biological activities.Herein, the scope of various aromatic heterocycles as dienophiles in the 1,3,5-triazine IEDDA reaction is reviewed. Moreover, both experimental and theoretical studies of the mechanisms for this interesting cascade IEDDA reaction are discussed. Finally, applications of this new type (aromatic heterocycles as dienophiles with 1,3,5-triazines as azadienes) of IEDDA reaction are also covered.
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Affiliation(s)
- Guoxing Xu
- The Center for Combinatorial Chemistry and Drug Discovery of Jilin University, The School of Pharmaceutical Sciences, Jilin University, 1266 Fujin Road, Changchun, Jilin 130021, P.R. China
| | - Xu Bai
- The Center for Combinatorial Chemistry and Drug Discovery of Jilin University, The School of Pharmaceutical Sciences, Jilin University, 1266 Fujin Road, Changchun, Jilin 130021, P.R. China
| | - Qun Dang
- The Center for Combinatorial Chemistry and Drug Discovery of Jilin University, The School of Pharmaceutical Sciences, Jilin University, 1266 Fujin Road, Changchun, Jilin 130021, P.R. China
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Pitre SP, Scaiano JC, Yoon TP. Photocatalytic Indole Diels-Alder Cycloadditions Mediated by Heterogeneous Platinum-Modified Titanium Dioxide. ACS Catal 2017; 7:6440-6444. [PMID: 29104813 DOI: 10.1021/acscatal.7b02223] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Indole alkaloids represent an important class of molecules, with many naturally occurring derivatives possessing significant biological activity. One area that requires further development in the synthesis of indole derivatives is the Diels-Alder reaction. In this work, we expand on our previously developed heterogeneous protocol for the [4+2] cycloaddition of indoles and electron-rich dienes mediated by platinum nanoparticles supported on titanium dioxide semiconductor particles (Pt(0.2%)@TiO2) with visible-light irradiation. This reaction proceeds with broad scope and is more efficient per incident photon than the previous homogeneous method, and the catalyst can be easily recycled and reused.
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Affiliation(s)
- Spencer P. Pitre
- Department
of Chemistry and Biomolecular Sciences and Centre for Catalysis Research
and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
| | - Juan C. Scaiano
- Department
of Chemistry and Biomolecular Sciences and Centre for Catalysis Research
and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
| | - Tehshik P. Yoon
- Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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Feng M, Jiang X. Stereoselective construction of a key hydroindole precursor of epidithiodiketopiperazine (ETP) natural products. Chem Commun (Camb) 2015; 50:9690-2. [PMID: 25017898 DOI: 10.1039/c4cc04148h] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
An asymmetric synthetic strategy for constructing the divergent-synthesis monomer of epidithiodiketopiperazine (ETP) natural products has been successfully developed. The functionalized 2,3,3a,4,7,7a-hexahydroindole scaffold was constructed by a diastereoselective inverse electron-demand Diels-Alder (IEDDA) reaction.
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Affiliation(s)
- Minghao Feng
- Shanghai Key Laboratory of Green Chemistry and Chemical Process, Department of Chemistry, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, P. R. China.
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Andreini M, De Paolis M, Chataigner I. Thiourea-catalyzed dearomatizing [4+2] cycloadditions of 3-nitroindole. CATAL COMMUN 2015. [DOI: 10.1016/j.catcom.2014.07.042] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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5
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Yang G, Jia Q, Chen L, Du Z, Wang J. Direct access to pyrimidines through organocatalytic inverse-electron-demand Diels–Alder reaction of ketones with 1,3,5-triazine. RSC Adv 2015. [DOI: 10.1039/c5ra16995j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
An organocatalytic inverse-electron-demand Diels–Alder reaction of ketones with 1,3,5-triazine through enamine catalysis has been developed.
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Affiliation(s)
- Gongming Yang
- Allan H. Conney Laboratory for Anticancer Research
- Guangdong University of Technology
- China
| | - Qianfa Jia
- Allan H. Conney Laboratory for Anticancer Research
- Guangdong University of Technology
- China
| | - Lei Chen
- Allan H. Conney Laboratory for Anticancer Research
- Guangdong University of Technology
- China
| | - Zhiyun Du
- Allan H. Conney Laboratory for Anticancer Research
- Guangdong University of Technology
- China
| | - Jian Wang
- Allan H. Conney Laboratory for Anticancer Research
- Guangdong University of Technology
- China
- Department of Chemistry
- National University of Singapore
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Guney T, Lee JJ, Kraus GA. First Inverse Electron-Demand Diels–Alder Methodology of 3-Chloroindoles and Methyl Coumalate to Carbazoles. Org Lett 2014; 16:1124-7. [DOI: 10.1021/ol403733n] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Tezcan Guney
- Department of Chemistry and
NSF Engineering Research Center for Biorenewable Chemicals, Iowa State University, Ames, Iowa 50011, United States
| | - Jennifer J. Lee
- Department of Chemistry and
NSF Engineering Research Center for Biorenewable Chemicals, Iowa State University, Ames, Iowa 50011, United States
| | - George A. Kraus
- Department of Chemistry and
NSF Engineering Research Center for Biorenewable Chemicals, Iowa State University, Ames, Iowa 50011, United States
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De Rosa M, Arnold D, Hartline D. Four Mechanisms in the Reactions of 3-Aminopyrrole with 1,3,5-Triazines: Inverse Electron Demand Diels–Alder Cycloadditions vs SNAr Reactions via Uncatalyzed and Acid-Catalyzed Pathways. J Org Chem 2013; 78:8614-23. [DOI: 10.1021/jo4012915] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michael De Rosa
- Department of Chemistry, Penn State Brandywine, 25 Yearsley Mill Road, Media, Pennsylvania 19063, United States
| | - David Arnold
- Department of Chemistry, Penn State Brandywine, 25 Yearsley Mill Road, Media, Pennsylvania 19063, United States
| | - Douglas Hartline
- Department of Chemistry, Penn State Brandywine, 25 Yearsley Mill Road, Media, Pennsylvania 19063, United States
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Wang L, Huang J, Gong X, Wang J. Highly Regioselective Organocatalyzed Synthesis of Pyrazoles from Diazoacetates and Carbonyl Compounds. Chemistry 2013; 19:7555-60. [DOI: 10.1002/chem.201300047] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Revised: 02/19/2013] [Indexed: 11/10/2022]
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Kawano M, Kiuchi T, Negishi S, Tanaka H, Hoshikawa T, Matsuo JI, Ishibashi H. Regioselective Inter- and Intramolecular Formal [4+2] Cycloaddition of Cyclobutanones with Indoles and Total Synthesis of (±)-Aspidospermidine. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/anie.201206734] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Kawano M, Kiuchi T, Negishi S, Tanaka H, Hoshikawa T, Matsuo JI, Ishibashi H. Regioselective Inter- and Intramolecular Formal [4+2] Cycloaddition of Cyclobutanones with Indoles and Total Synthesis of (±)-Aspidospermidine. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201206734] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Albrecht Ł, Dickmeiss G, Weise CF, Rodríguez-Escrich C, Jørgensen KA. Dienamine-Mediated Inverse-Electron-Demand Hetero-Diels-Alder Reaction by Using an Enantioselective H-Bond-Directing Strategy. Angew Chem Int Ed Engl 2012; 51:13109-13. [DOI: 10.1002/anie.201207122] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Indexed: 11/10/2022]
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Albrecht Ł, Dickmeiss G, Weise CF, Rodríguez-Escrich C, Jørgensen KA. Dienamine-Mediated Inverse-Electron-Demand Hetero-Diels-Alder Reaction by Using an Enantioselective H-Bond-Directing Strategy. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201207122] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ziegler RE, Tan SJ, Kam TS, Porco JA. Development of an alkaloid-pyrone annulation: synthesis of pleiomaltinine. Angew Chem Int Ed Engl 2012; 51:9348-51. [PMID: 22893619 PMCID: PMC3574645 DOI: 10.1002/anie.201204093] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Indexed: 11/10/2022]
Abstract
Odd Couple Methodology for the synthesis of alkaloid-pyrones using a novel pyrone annulation of β–carbolines and indoles with 3-siloxy-4-pyrones is reported. The approach has enabled semisynthesis of the unprecedented alkaloid-pyrone pleiomaltinine from the plant-derived indole-alkaloid pleiocarpamine.
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Affiliation(s)
- Robert E. Ziegler
- Department of Chemistry, Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA, Fax: (+1) 617-358-2847
| | - Shin-Jowl Tan
- Department of Chemistry, University of Malaya, Kuala Lumpur, Malaysia 50603
| | - Toh-Seok Kam
- Department of Chemistry, University of Malaya, Kuala Lumpur, Malaysia 50603
| | - John A. Porco
- Department of Chemistry, Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA, Fax: (+1) 617-358-2847
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Ziegler RE, Tan SJ, Kam TS, Porco JA. Development of an Alkaloid-Pyrone Annulation: Synthesis of Pleiomaltinine. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201204093] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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15
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Xu G, Zheng L, Wang S, Dang Q, Bai X. Synthesis of Electron-Deficient 1,3,5-Triazines as Potential Azadienes for Inverse-Electron-Demand Diels–Alder Reactions. SYNTHETIC COMMUN 2010. [DOI: 10.1080/00397910902978031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Guoxing Xu
- a The Center for Combinatorial Chemistry and Drug Discovery, College of Chemistry and School of Pharmaceutical Sciences, Jilin University , Changchun, China
| | - Lianyou Zheng
- a The Center for Combinatorial Chemistry and Drug Discovery, College of Chemistry and School of Pharmaceutical Sciences, Jilin University , Changchun, China
| | - Shixue Wang
- a The Center for Combinatorial Chemistry and Drug Discovery, College of Chemistry and School of Pharmaceutical Sciences, Jilin University , Changchun, China
| | - Qun Dang
- a The Center for Combinatorial Chemistry and Drug Discovery, College of Chemistry and School of Pharmaceutical Sciences, Jilin University , Changchun, China
| | - Xu Bai
- a The Center for Combinatorial Chemistry and Drug Discovery, College of Chemistry and School of Pharmaceutical Sciences, Jilin University , Changchun, China
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16
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[4+2] Cycloaddition Reactions of Indole Derivatives. TOPICS IN HETEROCYCLIC CHEMISTRY 2010. [DOI: 10.1007/7081_2010_55] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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17
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Victoria Gómez M, Aranda AI, Moreno A, Cossío FP, de Cózar A, Díaz-Ortiz Á, de la Hoz A, Prieto P. Microwave-assisted reactions of nitroheterocycles with dienes. Diels–Alder and tandem hetero Diels–Alder/[3,3] sigmatropic shift. Tetrahedron 2009. [DOI: 10.1016/j.tet.2009.04.065] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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18
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De Rosa M, Arnold D. Electronic and Steric Effects on the Mechanism of the Inverse Electron Demand Diels−Alder Reaction of 2-Aminopyrroles with 1,3,5-Triazines: Identification of Five Intermediates by 1H, 13C, 15N, and 19F NMR Spectroscopy. J Org Chem 2008; 74:319-28. [DOI: 10.1021/jo8019626] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Michael De Rosa
- Department of Chemistry, Penn State Brandywine, 25 Yearsley Mill Road, Media, Pennsylvania 19063
| | - David Arnold
- Department of Chemistry, Penn State Brandywine, 25 Yearsley Mill Road, Media, Pennsylvania 19063
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Kimura M, Horino Y, Mori M, Tamaru Y. Chameleon Reactivity of the Allene Bond of 4-Vinylidene-2-oxazolidinone: Novel Through-Space Conjugative Nucleophilic Addition of Electron-Rich Alkenes and Hetero-Nucleophiles. Chemistry 2007; 13:9686-702. [PMID: 17768719 DOI: 10.1002/chem.200700691] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The Calpha==Cbeta double bond of allene carbamates 1 serves as an electron acceptor similar to the double bond of conjugated enones by means of a through-space interaction with the N--SO2 bond; the carbamate double bond is thus subject to nucleophilic addition for a wide variety of nucleophiles, which proceeds under mild conditions by heating at 70-100 degrees C. Depending on the kind of nucleophiles, 1 displays three different reaction modes: 1) Typically enol ethers and allylsilanes promote 1,3-sulfonyl migration of 1 and undergo the inverse electron demand Diels-Alder reaction with the 1-aza-1,3-butadiene intermediates II thus formed to furnish bicyclic 2-alkoxy-5-sulfonyltetrahydropyridines 2 and 2-silylmethyl-5-sulfonyltetrahydropyridines 3, respectively, with high regio- and stereoselectivity and retention of configuration of the double bonds of these electron-rich alkenes; 2) silanes (RnSiH4-n, n=1-3) and thiols deliver the hydride and the thiolate at the Cbeta carbon and promote the 1,3-sulfonyl migration, followed by protonation of the thus-formed carbamate anion (Z)-III to provide, for example, (Z)-4 a and (Z)-4 j, respectively; 3) alcohols simply add to the Calpha==Cbeta double bond and provide (E)-6. Usually, the reaction with alcohols is accompanied by the second pathway, giving rise to, for example, (Z)-4 b in addition to (E)-6 b. Phenol engages in the third pathway and provides (E)-6 g exclusively. Heteroaromatics, such as furans and benzofurans follow the first pathway, however, in a different regioselectivity from enol ethers and allylsilanes, delivering the oxygen atom at the 3-position of 5-sulfonyltetrahydropyridines (2 g and 2 h). Indoles, on the other hand, show a dichotomy, equally enjoying the first and the third pathways and provide mixtures of (E)-7 and (E)-8, respectively.
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Affiliation(s)
- Masanari Kimura
- Graduate School of Science and Technology, Department of Applied Chemistry, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
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Roy S, Kishbaugh TL, Jasinski JP, Gribble GW. 1,3-Dipolar cycloaddition of 2- and 3-nitroindoles with azomethine ylides. A new approach to pyrrolo[3,4-b]indoles. Tetrahedron Lett 2007. [DOI: 10.1016/j.tetlet.2006.12.125] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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21
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Shibasaki M, Ohshima T. Recent studies on the synthesis of strychnine. THE ALKALOIDS. CHEMISTRY AND BIOLOGY 2007; 64:103-138. [PMID: 18085330 DOI: 10.1016/s1099-4831(07)64003-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Affiliation(s)
- Masakatsu Shibasaki
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
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Sato S, Fujino T, Isobe H, Nakamura E. Diels–Alder Reaction of Cyclopentadienone Acetal with Pyrrole and Indole. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2006. [DOI: 10.1246/bcsj.79.1288] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Padwa A, Lynch SM, Mejía-Oneto JM, Zhang H. Cycloaddition Chemistry of 2-Vinyl-Substituted Indoles and Related Heteroaromatic Systems. J Org Chem 2005; 70:2206-18. [PMID: 15760207 DOI: 10.1021/jo047834a] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] The intramolecular Diels-Alder cycloaddition reaction (IMDAF) of several N-phenylsulfonylindolyl-substituted furanyl carbamates containing a tethered pi-bond on the indole ring were examined as an approach to the iboga alkaloid catharanthine. Only in the case where the tethered pi-bond contained two carbomethoxy groups did the [4 + 2]-cycloaddition occur. Push-pull dipoles generated from the Rh(II)-catalyzed reaction of diazo imides, on the other hand, undergo successful intramolecular 1,3-dipolar cycloaddition across both alkenyl and heteroaromatic pi-bonds to provide novel pentacyclic compounds in good yield and in a stereocontrolled fashion. The facility of the cycloaddition was found to be critically dependent on conformational factors in the transition state. Ligand substitution in the rhodium(II) catalyst markedly altered the product ratio between [3 + 2]-cycloaddition and intramolecular C-H insertion. The variation in reactivity reflects the difference in electrophilicity between the various rhodium carbenoid intermediates. Intramolecular C-H insertion is enhanced with the more electrophilic carbene generated using Rh(II) perfluorobutyrate.
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Affiliation(s)
- Albert Padwa
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
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Mejía-Oneto JM, Padwa A. Intramolecular [3 + 2]-Cycloaddition Reaction of Push−Pull Dipoles Across Heteroaromatic π-Systems. Org Lett 2004; 6:3241-4. [PMID: 15355022 DOI: 10.1021/ol048915w] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] Push-pull dipoles generated from the Rh(II)-catalyzed reaction of diazo imides containing tethered heteroaromatic rings undergo successful [3 + 2]-cycloaddition across the 2,3-pi-bond to provide novel pentacyclic compounds in good to excellent yields in a stereocontrolled fashion. The facility of the cycloaddition is critically dependent on conformational factors in the transition state.
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Blattes E, Fleury MB, Largeron M. Simultaneously Electrogenerated Cycloaddition Partners for Regiospecific Inverse-Electron-Demand Diels−Alder Reactions: A Route for Polyfunctionalized 1,4-Benzoxazine Derivatives. J Org Chem 2004; 69:882-90. [PMID: 14750818 DOI: 10.1021/jo035614b] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A multistep one-pot electrochemical synthesis of a variety of complex 2-alkylamino-1,4-benzoxazine derivatives is described. The reactions are regiospecific and diastereospecific in the case of heterocyclic annulation. This cascade sequence, wherein both cycloaddition partners are generated in situ, at room temperature, under metal-free conditions, allows the inverse-electron-demand Diels-Alder reaction of an o-iminoquinone diene and a secondary alkylenamine dienophile, two chemically nonaccessible unstable entities. To increase the molecular diversity, a variant in which the enamine is separately prepared completes the aforementioned procedure. The extension of this reaction should be useful to generate libraries of heterocycles.
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Affiliation(s)
- Estelle Blattes
- UMR 8638 CNRS - Université René Descartes, Synthèse et Structure de Molécules d'Intérêt Pharmacologique, Faculté des Sciences Pharmaceutiques et Biologiques, 4 Avenue de l'Observatoire, 75270 Paris Cedex 06, France
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Kurbatov S, Goumont R, Marrot J, Terrier F. The nitroolefinic behavior of 4-nitrobenzodifuroxan. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2003.11.080] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Bodwell GJ, Li J. Concise synthesis and transannular inverse electron demand Diels-Alder reaction of [3](3,6)pyridazino[3](1,3)indolophane. Rapid access to a pentacyclic indoloid system. Org Lett 2002; 4:127-30. [PMID: 11772107 DOI: 10.1021/ol017014+] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] The title compound was synthesized concisely from indole. A 2-fold sequential hydroboration/Suzuki-Miyaura cross-coupling was employed to generate the cyclophane. When heated in N,N-diethylaniline, it underwent a transannular inverse electron demand Diels-Alder (IEDDA) reaction to form a pentacyclic product, which appears to be well suited as a precursor to a variety of indole alkaloids such as strychnine.
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Affiliation(s)
- Graham J Bodwell
- Department of Chemistry, Memorial University of Newfoundland, St. John's, Newfoundland, Canada, A1B 3X7.
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Kishbaugh TL, Gribble GW. Diels–Alder reactions of 2- and 3-nitroindoles. A simple hydroxycarbazole synthesis. Tetrahedron Lett 2001. [DOI: 10.1016/s0040-4039(01)00854-1] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Ginn JD, Lynch SM, Padwa A. Intramolecular [4+2]-cycloaddition reactions of cyclic 2-thiomethyl-5-amidofurans. Tetrahedron Lett 2000. [DOI: 10.1016/s0040-4039(00)01455-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Intramolecular Inverse Electron Demand Diels–Alder Reactions of Tryptamine with Tethered Heteroaromatic Azadienes. Tetrahedron 2000. [DOI: 10.1016/s0040-4020(00)00003-x] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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