1
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Meiszter E, Gazdag T, Mayer PJ, Kunfi A, Holczbauer T, Sulyok-Eiler M, London G. Revisiting Hafner's Azapentalenes: The Chemistry of 1,3-Bis(dimethylamino)-2-azapentalene. J Org Chem 2024; 89:5941-5951. [PMID: 38630009 PMCID: PMC11077492 DOI: 10.1021/acs.joc.3c02564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 03/19/2024] [Accepted: 04/03/2024] [Indexed: 05/04/2024]
Abstract
Stable azaheterocyclic derivatives of pentalene have been reported by the group of Hafner in the 1970s. However, these structures remained of low interest until recently, when they started to be investigated in the context of organic light-emitting diodes' (OLEDs') development. Herein, we revisit the synthesis of stable azapentalene derivative 1,3-bis(dimethylamino)-2-azapentalene and further explore its properties both computationally and experimentally. Beyond the reproduction and optimization of some previously reported transformations, such as formylation and amine substitution, the available scope of reactions was expanded with azo-coupling, selective halogenations, and cross-coupling reactions.
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Affiliation(s)
- Enikő Meiszter
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, HUN-REN Research Centre
for Natural Sciences, Magyar tudósok krt. 2, 1117 Budapest, Hungary
- Department
of Organic Chemistry and Technology, Faculty of Chemical Technology
and Biotechnology, Budapest University of
Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
| | - Tamás Gazdag
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, HUN-REN Research Centre
for Natural Sciences, Magyar tudósok krt. 2, 1117 Budapest, Hungary
- Hevesy
György PhD School of Chemistry, Eötvös
Loránd University, Pázmány Péter Sétány 1/a, 1117 Budapest, Hungary
| | - Péter J. Mayer
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, HUN-REN Research Centre
for Natural Sciences, Magyar tudósok krt. 2, 1117 Budapest, Hungary
| | - Attila Kunfi
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, HUN-REN Research Centre
for Natural Sciences, Magyar tudósok krt. 2, 1117 Budapest, Hungary
| | - Tamás Holczbauer
- Chemical
Crystallography Research Laboratory and Stereochemistry Research Group,
Institute for Organic Chemistry, HUN-REN
Research Centre for Natural Sciences, Magyar tudósok krt. 2, 1117 Budapest, Hungary
| | - Máté Sulyok-Eiler
- Hevesy
György PhD School of Chemistry, Eötvös
Loránd University, Pázmány Péter Sétány 1/a, 1117 Budapest, Hungary
- Laboratory
of Structural Chemistry and Biology, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter
Sétány 1/a, 1117 Budapest, Hungary
| | - Gábor London
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, HUN-REN Research Centre
for Natural Sciences, Magyar tudósok krt. 2, 1117 Budapest, Hungary
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2
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Konishi A, Yasuda M. Breathing New Life into Nonalternant Hydrocarbon Chemistry: Syntheses and Properties of Polycyclic Hydrocarbons Containing Azulene, Pentalene, and Heptalene Frameworks. CHEM LETT 2021. [DOI: 10.1246/cl.200650] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Akihito Konishi
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
- Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Makoto Yasuda
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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3
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Shoji T, Miura K, Ariga Y, Yamazaki A, Ito S, Yasunami M. Synthesis of thiophene-fused heptalenes by cycloaddition of azulenothiophenes with dimethyl acetylenedicarboxylate. Sci Rep 2020; 10:12477. [PMID: 32719442 PMCID: PMC7385116 DOI: 10.1038/s41598-020-69425-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 07/06/2020] [Indexed: 11/09/2022] Open
Abstract
Heptalene has a fused structure of two cycloheptatrienes which is one of the non-aromatic bicyclic molecules with a 12π-electronic structure. We report herein the synthesis of thiophene-fused heptalene derivatives from the corresponding azulenothiophenes via cycloaddition reaction with dimethyl acetylenedicarboxylate. Their structure was clarified by single-crystal X-ray structural analysis. The electronic properties of the thiophene-fused heptalenes obtained by this study were characterized by UV/Vis and fluorescence spectroscopy measurements. The electrochemical features of these derivatives were also examined by voltammetry and spectroelectrochemical experiments.
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Affiliation(s)
- Taku Shoji
- Department of Material Science, Graduate School of Science and Technology, Shinshu University, Matsumoto, Nagano, 390-8621, Japan.
| | - Kota Miura
- Department of Material Science, Graduate School of Science and Technology, Shinshu University, Matsumoto, Nagano, 390-8621, Japan
| | - Yukino Ariga
- Department of Material Science, Graduate School of Science and Technology, Shinshu University, Matsumoto, Nagano, 390-8621, Japan
| | - Akari Yamazaki
- Department of Material Science, Graduate School of Science and Technology, Shinshu University, Matsumoto, Nagano, 390-8621, Japan
| | - Shunji Ito
- Graduate School of Science and Technology, Hirosaki University, Hirosaki, Aomori, 036-8561, Japan
| | - Masafumi Yasunami
- Department of Chemical Biology and Applied Chemistry, College of Engineering, Nihon University, Koriyama, Fukushima, 963-8642, Japan
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4
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Briling KR, Laikov DN. Heptalene Synthesis by Addition of Aryl Acetylenes to
Azulenes. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2020. [DOI: 10.1134/s1070428020040028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Kosai T, Ishida S, Iwamoto T. Transformation of azulenes to bicyclic [4]dendralene and heptafulvene derivatives via photochemical cycloaddition of dialkylsilylene. Chem Commun (Camb) 2015; 51:10707-9. [DOI: 10.1039/c5cc03424h] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Regioselective cycloaddition of dialkylsilylene upon irradiation converts azulene and guaiazulene to bicyclic [4]dendralene and heptafulvene derivatives, respectively.
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Affiliation(s)
- Tomoyuki Kosai
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Sendai 980-8578
- Japan
| | - Shintaro Ishida
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Sendai 980-8578
- Japan
| | - Takeaki Iwamoto
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Sendai 980-8578
- Japan
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6
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Hansen HJ, Uebelhart P, Lehto E. A Thermal Potential [6+4] 2H-Transfer Reaction in a Cyclic Dimer of Dimethyl 2a,8a-Dihydrocyclopent[c,d]azulene-1,2-dicarboxylate. HETEROCYCLES 2014. [DOI: 10.3987/com-13-s(s)76] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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7
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8
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Klärner FG, Dogan B, Roth WR, Hafner K. Cycloadditionen des Azulens unter hohem Druck. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.19820940926] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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9
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Harre M, Raddatz P, Walenta R, Winterfeldt E. 4-Oxo-2-cyclopentenylacetat - ein Synthesebaustein. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.19820940704] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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10
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Hafner K, Goltz M. Einfache Umwandlung des Azulen-Systems in das Pentalen-System. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.19820940914] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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11
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Synthesis and properties of 1,6-methano[10]annuleno[3,4-c]thiophene and its 1,3-dicyano derivative. Tetrahedron Lett 2005. [DOI: 10.1016/j.tetlet.2005.08.145] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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12
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Bernhard W, Brügger P, Daly JJ, Schönholzer P, Weber RH, Hansen HJ. First Optically Active Heptalenes and their Absolute Configuration. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19850680215] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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13
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14
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Hafner K, Knaup GL, Lindner HJ, Flöter HC. Synthesis and Dynamic Properties of Chiral Heptalenes. ACTA ACUST UNITED AC 2003. [DOI: 10.1002/anie.198502121] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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15
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16
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Singh G, Linden A, Abou-Hadeed K, Hansen HJ. New Products from the Heptalene-Forming Reaction of Azulenes and Acetylenedicarboxylates in Polar Media. Helv Chim Acta 2002. [DOI: 10.1002/1522-2675(200201)85:1<27::aid-hlca27>3.0.co;2-f] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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17
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Oda M, Sakamoto A, Miyatake R, Kuroda S. Formation, characterization, and some reactions of spiro[cyclobutane-1,1′-1′H-azulenium] ion. Tetrahedron 1999. [DOI: 10.1016/s0040-4020(99)00740-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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18
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19
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Abou-Hadeed K, Hansen HJ. A ?One-Pot? Anellation Method for the Transformation of Heptalene-4,5-dicarboxylates into Benzo[a]heptalenes. Helv Chim Acta 1997. [DOI: 10.1002/hlca.19970800821] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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20
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Briquet AAS, Uebelhart P, Hansen HJ. Double-Bond Shifts in [4n]Annulenes as a New Principle for Molecular Switches: First Results with Dimethyl Heptalene-1,2- and -4,5-dicarboxylates. Helv Chim Acta 1996. [DOI: 10.1002/hlca.19960790819] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Fallahpour RA, Hansen HJ. Formation and Thermal Rearrangement of Dimethyl Tricyclo[6.2.2.01,7]dodeca-2,4,6,9,11-pentaene-9,10-dicarboxylates. Helv Chim Acta 1995. [DOI: 10.1002/hlca.19950780805] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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22
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Fallahpour RA, Sigrist R, Hansen HJ. Reaction of Hydroxymethyl- and Alkyl-Substituted Azulenes with Manganese Dioxide. Helv Chim Acta 1995. [DOI: 10.1002/hlca.19950780603] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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23
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24
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Yasunami M, Sato T, Yoshifuji M. Reaction of benz[a]azulene with dimethyl acetylenedicarboxylate. Formation of a π-bond fixed heptalene derivative. Tetrahedron Lett 1995. [DOI: 10.1016/0040-4039(94)02176-c] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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25
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Briquet AAS, Hansen HJ. Thermal and Ru-catalyzed Reactions of Styryl-Substituted Azulenes with Dimethyl Acetylenedicarboxylate. Helv Chim Acta 1994. [DOI: 10.1002/hlca.19940770723] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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26
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Kuroda S, Mouri M, Hayashi K, Oda M, Yamada (LM, Shimao I, Osaki H, Yasunami M. Synthesis and Properties of Azuleno[1,2-a]acenaphthylene and Dimethyl acenaphthyleno[1,2-d]heptalene-8,9-dicarboxylate. CHEM LETT 1994. [DOI: 10.1246/cl.1994.85] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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27
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Rippert AJ, Linden A, Hansen HJ. Cationic RhI Complexes of Azulenes and Their Catalytic Activity on the Formation of Heptalene-1,2-dicarboxylates from Dimethyl Acetylenedicarboxylate and Azulenes. Helv Chim Acta 1993. [DOI: 10.1002/hlca.19930760812] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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28
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Chen Y, Hansen HJ. Thermal Reaction of Azulene and Some of Its Symmetrically Substituted Methyl Derivatives with Dimethyl Acetylenedicarboxylate. Helv Chim Acta 1993. [DOI: 10.1002/hlca.19930760111] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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29
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Uebelhart P, Hansen HJ. Thermal Reactions of Guaiazulene and Its 3-Methyl Derivative with Dimethyl Acetylenedicarboxylate. Helv Chim Acta 1992. [DOI: 10.1002/hlca.19920750804] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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30
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Chen Y, Kunz RW, Uebelhart P, Weber RH, Hansen HJ. Thermal Reaction of Highly Alkylated Azulenes with Dimethyl Acetylenedicarboxylate: HOMO(Azulene)vs. SHOMO(Azulene) Control in the Primary Thermal Addition Step. Helv Chim Acta 1992. [DOI: 10.1002/hlca.19920750803] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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31
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32
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Rippert AJ, Hansen HJ. Ru-Catalyzed Heptalene Formation from Azulenes and Dimethyl Acetylenedicarboxylate. Helv Chim Acta 1992. [DOI: 10.1002/hlca.19920750707] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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33
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Abe N. Reactions of 2-Aminoazulenes with Electron-Deficient Acetylenes. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1991. [DOI: 10.1246/bcsj.64.2393] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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34
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35
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Hafner K, Knaup GL, Lindner HJ. Syntheses and Dynamic Behavior of Chiral Heptalenes. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1988. [DOI: 10.1246/bcsj.61.155] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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36
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Müllen K. Neue reduktive Umwandlungen cyclischer ungesättigter Kohlenwasserstoffe. Angew Chem Int Ed Engl 1987. [DOI: 10.1002/ange.19870990306] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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37
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Hafner K, Knaup GL, Lindner HJ. Synthese und dynamische Eigenschaften substituierter Cyclohepta[ef]heptalene. Angew Chem Int Ed Engl 1986. [DOI: 10.1002/ange.19860980722] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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38
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Hafner K, Knaup GL, Lindner HJ, Flöter HC. Synthese und dynamische Eigenschaften chiraler Heptalene. Angew Chem Int Ed Engl 1985. [DOI: 10.1002/ange.19850970311] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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39
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Neunhoeffer H, Schaberger FD. Zur Synthese von 1,2,4-Triazinen, X. Cycloadditionen mit Azabenzolen, XV. Versuche zur Synthese von 1-Azaheptalenen. ACTA ACUST UNITED AC 1983. [DOI: 10.1002/jlac.198319831102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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40
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Hafner K, Goltz M. Simple Transformation of the Azulene System into the Pentalene System. ACTA ACUST UNITED AC 1982. [DOI: 10.1002/anie.198206951] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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41
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Harre M, Raddatz P, Walenta R, Winterfeldt E. 4-Oxo-2-cyclopentenyl Acetate?A Synthetic Intermediate. ACTA ACUST UNITED AC 1982. [DOI: 10.1002/anie.198204801] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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42
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Kl�rner FG, Dogan B, Roth WR, Hafner K. Organische Reaktionen unter hohem Druck, I. Cycloadditionen des Azulens unter hohem Druck. Angew Chem Int Ed Engl 1982. [DOI: 10.1002/anie.198214990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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43
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Tochtermann W, Rösner P. Synthese mittlerer und großer Ringe, II: Funktionalisierte Cyclodecene und Cyclodecadiene durch Ringerweiterung des Cyclooctins. ACTA ACUST UNITED AC 1981. [DOI: 10.1002/cber.19811141124] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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44
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Vogel E, Kerimis D, Allison NT, Zellerhoff R, Wassen J. Heptalen-bis(tricarbonyleisen). Angew Chem Int Ed Engl 1979. [DOI: 10.1002/ange.19790910723] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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45
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Vogel E, Kerimis D, Allison NT, Zellerhoff R, Wassen J. Heptalenebis(tricarbonyliron). Angew Chem Int Ed Engl 1979. [DOI: 10.1002/anie.197905451] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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46
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Hafner K, Lindner HJ, Ude W. Überraschende Umwandlung von Azulen durch Cycloaddition mit 1-(Diethylamino)propin. Angew Chem Int Ed Engl 1979. [DOI: 10.1002/ange.19790910224] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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47
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Hafner K, Lindner HJ, Ude W. Surprising Transformation of Azulene by Cycloaddition with 1-(Diethylamino)propyne. Angew Chem Int Ed Engl 1979. [DOI: 10.1002/anie.197901611] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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48
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49
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Hafner K, Diehl H, Richarz W. Cycloadditions of Aceheptylene?A Facile Synthesis of Dicyclopenta[ef,kl]heptalenes. ACTA ACUST UNITED AC 1976. [DOI: 10.1002/anie.197601081] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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