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Liu L, Du L, Li B. Recent advances in 8π electrocyclization reactions. Chem Commun (Camb) 2023; 59:670-687. [PMID: 36597987 DOI: 10.1039/d2cc04805a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Medium-ring systems, which constitute a class of structurally intriguing and biologically important molecules, are present in many natural products and pharmaceuticals. However, the construction of these skeletons tends to be difficult because of the torsional strain of the medium-sized ring, and control of the selectivity is also challenging in these flexible skeletons. Electrocyclization is one of the most straightforward methods to construct medium-sized rings and this process typically proceeds in a stereospecific manner, resulting in the stereo-controlled formation of two neighboring stereocenters. At present, there are few studies on 8π electrocyclization, mainly focusing on the synthesis of small molecules, while the applications in the synthesis of functional materials and biological contexts are rare. This feature article highlights recent advances, from 2000 to 2022, in the 8π electrocyclization reaction. This study is organized into four sections based on the size/composition of the target ring, including the synthesis of aza-seven-membered, cycloheptene, cyclooctene and bicyclo[4,2,0]octane frameworks. We expect that this feature article will provide beneficial guidance for the selective construction of medium-ring skeletons.
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Affiliation(s)
- Lei Liu
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400044, China.
| | - Luan Du
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400044, China.
| | - Baosheng Li
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400044, China.
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2
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Neue B, Reiermann R, Fröhlich R, Wibbeling B, Bergander K, Würthwein EU. Isocyanide Cyclization Reactions: 4-Methylene-4H-benzo[d][1,3]oxazine, 3-Benzyl-4-methylene-3,4-dihydroquinazolines and 3-(4-Benzyl)-3H-quinazolin-4-ones - Experiment and Theory. European J Org Chem 2013. [DOI: 10.1002/ejoc.201300293] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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3
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Nedolya NA, Trofimov BA. [1,7]-Electrocyclization reactions in the synthesis of azepine derivatives. Chem Heterocycl Compd (N Y) 2013. [DOI: 10.1007/s10593-013-1236-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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4
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Neue B, Reiermann R, Gerdes K, Fröhlich R, Wibbeling B, Würthwein EU. Ring closure reactions of 2,6-diazaheptatrienyl metal compounds: synthesis of 3-aminoindole derivatives and 14-membered macrocyclic dimers. J Org Chem 2011; 76:8794-806. [PMID: 21988327 DOI: 10.1021/jo201521v] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
2,6-Diazaheptatrienyl metal compounds 6(-)K(+) are easily accessible from the corresponding diimines 6 by deprotonation using KO-t-Bu as base. According to quantum chemical calculations, they are, in comparison to other isomeric species with nitrogen atoms in other positions, highly reactive intermediates, which undergo in dilute solution at 50 °C ring closure reactions to form 3-aminoindole derivatives 8/10. In contrast, in more concentrated solution at room temperature, the formation of 14-membered macrocyclces 13 as a result of formal dimerization is observed. The 3-aminoindole derivatives obtained in this work possess rare substitution patterns, and the macrocyclic compounds are essentially unknown. Two-fold vinylogous derivatives 7 give rise to tricyclic systems with δ-carboline backbone 12. The experimental results are interpreted using high-level DFT calculations with regard to the possible reaction mechanism and the nature of the transition state of the five-membered ring formation. The molecular structures in the solid state of all types of compounds were elucidated by X-ray diffraction.
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Affiliation(s)
- Benedikt Neue
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
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5
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Nedolya NA, Tarasova OA, Volostnykh OG, Albanov AI, Trofimov BA. Simultaneous synthesis of 4,5-dihydro-3H-azepines and 3H-azepines, bearing alkoxy and alkylsulfanyl substituents, through metallation of 2-aza-1,3,5-trienes by t-BuOK. J Organomet Chem 2011. [DOI: 10.1016/j.jorganchem.2011.07.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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6
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Kleine T, Fröhlich R, Wibbeling B, Würthwein EU. Cyclization Reactions of 3,4-Diazaheptatrienyl Metal Compounds. Pyridines from an Anionic Analogue of the Fischer Indole Synthesis: Experiment and Theory. J Org Chem 2011; 76:4591-9. [DOI: 10.1021/jo200487v] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tillmann Kleine
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, D-48149 Münster, Germany
| | - Roland Fröhlich
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, D-48149 Münster, Germany
| | - Birgit Wibbeling
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, D-48149 Münster, Germany
| | - Ernst-Ulrich Würthwein
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, D-48149 Münster, Germany
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7
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Kleine T, Bergander K, Fröhlich R, Wibbeling B, Würthwein EU. Ring-Closure Reactions of 1,2-Diaza-4,5-benzoheptatrienyl Metal Compounds: Experiment and Theory. J Org Chem 2011; 76:1979-91. [DOI: 10.1021/jo2001534] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tillmann Kleine
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, D-48149 Münster, Germany
| | - Klaus Bergander
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, D-48149 Münster, Germany
| | - Roland Fröhlich
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, D-48149 Münster, Germany
| | - Birgit Wibbeling
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, D-48149 Münster, Germany
| | - Ernst-Ulrich Würthwein
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, D-48149 Münster, Germany
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8
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Shagun VA, Nedolya NA, Tarasova OA, Volostnykh OG, Kazheva ON, Chekhlov AN, Aleksandrov GG, D’yachenko OA. Reactions of heterocumulenes with organometallic reagents: XVI. Quantum-chemical study on the mechanisms of formation of homo- and heteroannular azacycloheptadienes in reactions of 2-aza-1,3,5-trienes with potassium tert-butoxide. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2011. [DOI: 10.1134/s1070428010120146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Nedolya NA, Tarasova OA, Volostnykh OG, Albanov AI, Trofimov BA. Unexpected transformations of 1-aza-1,3,4-trienes in alcoholic potassium hydroxide. New classes of aza dienes. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2011. [DOI: 10.1134/s1070428011010209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Sajitz M, Fröhlich R, Würthwein EU. 1,7-Electrocyclization Reactions of 2-Aza-4,5-benzoheptatrienyl- and 4-Aza-6,7-benzononatetraenyllithium Compounds: Synthesis of Novel 2-Benzazepines and (Benzocyclooctenyl)amines. European J Org Chem 2009. [DOI: 10.1002/ejoc.200801295] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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11
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Lyaskovskyy V, Fröhlich R, Würthwein EU. Mechanistic Study on Rearrangement Cascades Starting from Annulated 2-Aza-hepta-2,4-dienyl-6-ynyl Anions: Formation of Aniline and Azepine Derivatives. Chemistry 2007; 13:3113-9. [PMID: 17205595 DOI: 10.1002/chem.200601491] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Deprotonation of benzothiophene-derived alkynyl imine 11 with lithium diisopropylamide (LDA) and subsequent transmetalation with ZnCl2 etherate furnished azepine 12 upon aqueous workup. Similarly, alkynyl benzaldimine 1a gave a mixture of benzazepine 13 and naphthylamine 14. Allylic benzonitriles 15 a,b reacted to produce naphthylamine 16 upon deprotonation with LDA at room temperature. In an analogous manner, imino benzonitrile 17 may be converted into 4-amino isoquinoline 18 by means of an intramolecular nucleophilic attack on the nitrile function upon treatment with LDA. The allylic benzonitriles 19 a,b were prepared by LDA treatment of alkynyl imine 11. They were further converted to amino dibenzothiophene 20 by LDA deprotonation and aqueous workup. These various transformations represent the key steps of a multistep reaction cascade, which was previously postulated on the basis of quantum chemical calculations. Thus, all features of this complex rearrangement mechanism could now be confirmed experimentally. DFT calculations support the lower reactivity of zinc species in the ring-opening step compared to the lithium intermediates. All new compounds were completely characterized by spectroscopic data, including X-ray diffraction studies for the key compounds 12, 19 a, and 20.
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Affiliation(s)
- Volodymyr Lyaskovskyy
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
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12
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Lyaskovskyy V, Bergander K, Fröhlich R, Würthwein EU. Novel Synthesis of Azepine Derivatives via Copper-Mediated Cyclization of 2-Aza-hepta-2,4-dien-6-ynyl Anions. Intramolecular Addition of Organocopper Centers to the C−C Triple Bond. Org Lett 2007; 9:1049-52. [PMID: 17298076 DOI: 10.1021/ol063081y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Deprotonation of alkynyl imines 1 with LDA at low temperature and subsequent transmetalation with copper thiophenolate gives the annulated azepines 11a-i in 41-73% yield after aqueous workup. The key step of the reaction is a copper-mediated intramolecular nucleophilic attack at the triple bond. [reaction: see text]
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Affiliation(s)
- Volodymyr Lyaskovskyy
- Organisch-Chemisches Institut der Westfälischen Wilhelms-Universität Münster, D-48149 Münster, Germany
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13
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Dieker J, Fröhlich R, Würthwein EU. Substituted 3-Hydroxypyrroles from 1-Azapenta-1,4-dien-3-ones:The Aza-Nazarov Reaction – Synthesis and Quantum Chemical Calculations. European J Org Chem 2006. [DOI: 10.1002/ejoc.200600602] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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14
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Nedolya NA, Dmitrieva LL, Albanov AI, Klyba LV, Tarasova OA, Ushakov IA. Reactions of lithiated allenes with isothiocyanates: First example of deprotonation of 2-aza-1,3,5-trienes. Synthesis of 6-methoxy-2-methyl-3H-azepine and 3-methoxy-7-methyl-2-methylsulfanyl-4,5-dihydro-3H-azepine. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2006. [DOI: 10.1134/s1070428006030250] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Sagar P, Fröhlich R, Würthwein EU. Eine vielseitige Aminobenzanellierungsmethode durch Deprotonierung von 2-(1-Alkinyl)benzaldiminen und ähnlichen 2-Aza-2,4-heptadienyl-6-inen: eine mehrstufige Umlagerungskaskade. Angew Chem Int Ed Engl 2004. [DOI: 10.1002/ange.200461031] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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16
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Sagar P, Fröhlich R, Würthwein EU. A Versatile Aminobenzannulation Method Based on the Deprotonation of 2-(1-Alkynyl)benzaldimines and Similar 2-Aza-2,4-heptadienyl-6-ynes: A Multistep Rearrangement Cascade. Angew Chem Int Ed Engl 2004; 43:5694-7. [PMID: 15495156 DOI: 10.1002/anie.200461031] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Pramod Sagar
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149 Münster, Germany
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17
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Alickmann D, Fröhlich R, Maulitz A, Würthwein EU. Electrocyclization Reactions of 1-Aza- and 1-Oxapentadienyl and -heptatrienyl Cations: Synthesis of Pyrrole and Furan Derivatives. European J Org Chem 2002. [DOI: 10.1002/1099-0690(200205)2002:9%3c1523::aid-ejoc1523%3e3.0.co%3b2-s] [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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18
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Alickmann D, Fröhlich R, Maulitz A, Würthwein EU. Electrocyclization Reactions of 1-Aza- and 1-Oxapentadienyl and -heptatrienyl Cations: Synthesis of Pyrrole and Furan Derivatives. European J Org Chem 2002. [DOI: 10.1002/1099-0690(200205)2002:9<1523::aid-ejoc1523>3.0.co;2-s] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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20
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1,7-Electrocyclisation reactions of 2-azaheptatrienyl lithium compounds: Synthesis of 1-acyl-2,3-dihydroazepines. Tetrahedron 1996. [DOI: 10.1016/0040-4020(96)00938-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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