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Haghdadi M, Abaszade A, Abadian L, Nab N, Bosra HG. A theoretical study on the hetero-Diels–Alder reaction of phosphorous substituted diaza- and oxaza-alkenes with olefins derivatives. RSC Adv 2016. [DOI: 10.1039/c6ra15496d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
DFT studies indicated that a hetero-Diels–Alder reaction of 4-phosphinyl and 4-phosphonyl-1,2-diaza- and 1,2-oxaza-1,3-butadienes with some olefins take place via an asynchronous concerted mechanism through endo or exo transition states.
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Affiliation(s)
- M. Haghdadi
- Department of Chemistry
- Islamic Azad University
- Babol
- Iran
| | - A. Abaszade
- Department of Chemistry
- Islamic Azad University
- Babol
- Iran
| | - L. Abadian
- Department of Chemistry
- Islamic Azad University
- Babol
- Iran
| | - N. Nab
- Department of Chemistry
- Islamic Azad University
- Babol
- Iran
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Singh L, Singh Ishar MP, Elango M, Subramanian V, Gupta V, Kanwal P. Synthesis of Unsymmetrical Substituted 1,4-Dihydropyridines through Thermal and Microwave Assisted [4+2] Cycloadditions of 1-Azadienes and Allenic Esters. J Org Chem 2008; 73:2224-33. [DOI: 10.1021/jo702548b] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lakhwinder Singh
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar 143 005, Punjab, India, Chemical Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020, Tamilnadu, India, and P. G. Department of Physics, University of Jammu, Jammu Tawi-180 006, India
| | - M. P. Singh Ishar
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar 143 005, Punjab, India, Chemical Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020, Tamilnadu, India, and P. G. Department of Physics, University of Jammu, Jammu Tawi-180 006, India
| | - Munusamy Elango
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar 143 005, Punjab, India, Chemical Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020, Tamilnadu, India, and P. G. Department of Physics, University of Jammu, Jammu Tawi-180 006, India
| | - Venkatesan Subramanian
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar 143 005, Punjab, India, Chemical Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020, Tamilnadu, India, and P. G. Department of Physics, University of Jammu, Jammu Tawi-180 006, India
| | - Vivek Gupta
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar 143 005, Punjab, India, Chemical Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020, Tamilnadu, India, and P. G. Department of Physics, University of Jammu, Jammu Tawi-180 006, India
| | - Priyanka Kanwal
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar 143 005, Punjab, India, Chemical Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020, Tamilnadu, India, and P. G. Department of Physics, University of Jammu, Jammu Tawi-180 006, India
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Merino P, Tejero T, Chiacchio U, Romeo G, Rescifina A. A DFT study on the 1,3-dipolar cycloaddition reactions of C-(hetaryl) nitrones with methyl acrylate and vinyl acetate. Tetrahedron 2007. [DOI: 10.1016/j.tet.2006.11.073] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Itoh K, Kitoh K, Kishimoto S. Concerted and stepwise mechanisms in the DielsAlder and Michael reactions of furans with methyl 3-nitroacrylate Experimental and theoretical studies. CAN J CHEM 2006. [DOI: 10.1139/v06-013] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The DielsAlder reactions of the furans (1a1c) and methyl 3-nitroacrylate (2) produce the cycloadducts via a concerted mechanism. Then, the products subsequently undergo retro-DielsAlder reactions to give the Michael adducts via a stepwise mechanism. We have used both experimental and theoretical methods to investigate the mechanism for, and the regio- and stereo-selectivity in, the DielsAlder and Michael reactions. To account for the selectivity observed in these additions, we examined the frontier molecular orbitals involved, and to locate the transition states (TS), we employed a B3LYP/6-31G* level density functional calculation. We were able to explain the regio- and stereo-selectivity of the four possible DielsAlder adducts observed in the experiments by a comparison of their calculated activation energies, which ranged from 11 to 18 kcal/mol (1 cal = 4.184 J). The s-cis forms of the dienophile (2) were found to be more stable than the s-trans forms, both in the ground state and in the transition state. In addition, the endo transition structures for the ester group exhibited a lower energy barrier by 0.3 kcal/mol than their exo counterparts, a value that is in disagreement with the experimental results. The presence of the nitro group in 2 may play an important role in determining the selectivity. Our attempts to find a stepwise mechanism leading to the DielsAlder adduct via a zwitterion were unsuccessful. We did find that two stepwise processes lead to the formation of Michael adducts generated via an electrophilic attack by 2 at the α position of 1b and 1c, and an intramolecular proton-transfer mediated by the formation of a four-membered structure. The potential energies for these reactions showed values in the following ranges: 17 kcal/mol for 5a and 5b, and 11 to 12 kcal/mol for 7a and 7b for the first step, and, for the proton-transfer step, 4851 kcal/mol for 5a and 5b, and 4145 kcal/mol for 7a and 7b. Solvent effects in chloroform on the Michael addition did not appear in the electrophilic attack step (less than 4 kcal/mol), but the transition state of the later process was stabilized by 613 kcal/mol.Key words: DielsAlder reactions, Michael reactions, density functional method, furan, retro-DielsAlder reactions, solvent effect.
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López F, Castedo L, Mascareñas JL. A Theoretical Rationalization of the Asymmetric Induction in Sulfinyl-Directed [5C + 2C] Intramolecular Cycloadditions. J Org Chem 2003; 68:9780-6. [PMID: 14656107 DOI: 10.1021/jo035259p] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A computational DFT examination (B3LYP/6-31G and B3LYP/6-311+G//B3LYP/6-31G) of the thermal [5C + 2C] cycloaddditions of 6-acetoxy-3-pyranones and 3-silyloxy-4-pyrones with tethered alkenyl sulfoxides confirms that the high level of diastereofacial selectivity obtained is ultimately due to the preference of the alkenesulfinyl group to adopt a well-defined conformation in the transition state of the reaction. This conformation, which is different from that found in the ground state, is most probably dictated by dipolar interaction effects between the sulfoxide and the oxidopyrylium ylide intermediate.
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Affiliation(s)
- Fernando López
- Departamento de Química Orgánica y Unidad Asociada al CSIC, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
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Jin S, Wessig P, Liebscher J. Intermolecular and Intramolecular Diels−Alder Cycloadditions of 3-Ylidenepiperazine-2,5-diones and 5-Acyloxy-2(1H)-pyrazinones. J Org Chem 2001; 66:3984-97. [PMID: 11375024 DOI: 10.1021/jo0100897] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The 3-ylidenepiperazine-2,5-diones 16 and 39 and 5-acyloxy-2(1H)-pyrazinones 17 can serve as starting materials for the Diels-Alder reactions of alkenes and alkynes to the piperazine ring, under acidic conditions or in the presence of acetyl chloride, to afford tricyclic piperazine-2,5-diones 19, 20, 23-25, 27, 44, and 45. Intramolecular cycloadditions occur if 3-ylidenepiperazine-2,5-diones 30 and 32 are used as the starting materials. This procedure is a convenient path to bridged bicyclo[2.2.2]diazaoctane ring systems such as 31 and 33, the former being found in biologically active secondary mold metabolites, such as VM55599 (1) or brevianamide A (5), which have been isolated from various fungi. The synthesis of the indole compound 31 provided evidence for the proposed biochemical pathway with a Diels-Alder reaction as key step. Quantum chemical calculations have revealed that piperazinones with a cationic azadiene moiety are the most reactive species in Diels-Alder cycloadditions.
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Affiliation(s)
- S Jin
- Institut für Chemie, Humboldt-Universität Berlin, Hessische Strasse 1-2, 10115 Berlin, Germany
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