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Mechanistic studies on Diels-Alder [4þ2] cycloaddition reactions ofa,b-substituted cyclobutenones: Role of substituents in regio- andstereoselectivity
An article published by Elsevier Ltd and also available at http://dx.doi.org/10.1016/j.tet.2016.10.063
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| Format: | Article |
| Language: | English |
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Elsevier Ltd.
2020
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| _version_ | 1867613137975377920 |
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| access_status_str | Open Access |
| author | Fosu, Evans Tia, Richard Adei, Evans |
| author_browse | Adei, Evans Fosu, Evans Tia, Richard |
| author_facet | Fosu, Evans Tia, Richard Adei, Evans |
| author_sort | Fosu, Evans |
| collection | Thesis |
| description | An article published by Elsevier Ltd and also available at http://dx.doi.org/10.1016/j.tet.2016.10.063 |
| format | Article |
| id | oai:ir.knust.edu.gh:123456789/12650 |
| institution | KNUST (Ghana) |
| language | English |
| last_indexed | 2026-06-10T12:31:22.621Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from KNUSTSpace — Kwame Nkrumah University of Science & Technology (Ghana) |
| publishDate | 2020 |
| publishDateRange | 2020 |
| publishDateSort | 2020 |
| publisher | Elsevier Ltd. |
| publisherStr | Elsevier Ltd. |
| record_format | dspace |
| source_str | KNUSTSpace — Kwame Nkrumah University of Science & Technology (Ghana) |
| spelling | oai:ir.knust.edu.gh:123456789/12650 Mechanistic studies on Diels-Alder [4þ2] cycloaddition reactions ofa,b-substituted cyclobutenones: Role of substituents in regio- andstereoselectivity Fosu, Evans Tia, Richard Adei, Evans Diels-Alder cycloaddition Mechanism Regioselectivity Stereoselectivity Dane's diene Cyclobutenone An article published by Elsevier Ltd and also available at http://dx.doi.org/10.1016/j.tet.2016.10.063 Diels-Alder reactions of substituted cyclobutenones with 6-methoxy-1-vinyl-3,4-dihydronaphthaleneand methoxy-substituted-1,3-butadiene have been studied with DFT. In the reactions of 6-methoxy-1-vinyl-3,4-dihydronaphthalene with cyclobutenone anda-bromocyclobutenone, the formation of themetaandorthoisomers have the same barriers, indicating that the two isomers might be formed in equalproportions, contrary to earlier reports. The regiochemistry of the reaction is mainly controlled by theketone functionality at C1 on the dienophiles. In the reactions of methoxy-substituted-1,3-butadienewith cyclobutenone anda,b-substituted cyclobutenones theortho/endoandpara/endostereo-isomericpathways are the most favorable pathways, changing toexoselectivity when OH, Br, CH3are placedon theb-carbon of the cyclobutenone, but still withorthoandpararegioselectivity. The stereoselectivityis independent of the bulkiness of substituents. The stability of substituted cycloadducts are lowercompared to unsubstituted adducts and this explains why thea-cyanoketones anda-bromoketoneproducts readily undergotrans-methylation and angular-alkylation as electrophiles. KNUST 2020-07-08T10:39:54Z 2023-04-19T02:04:49Z 2020-07-08T10:39:54Z 2023-04-19T02:04:49Z 216-11-03 Article E. Fosu et al. Mechanistic studies on Diels-Alder [4þ2] cycloaddition reactions ofa,b-substituted cyclobutenones: Role of substituents in regio- andstereoselectivity. http://dx.doi.org/10.1016/j.tet.2016.10.063 https://ir.knust.edu.gh/handle/123456789/12650 en Elsevier Ltd. |
| spellingShingle | Diels-Alder cycloaddition Mechanism Regioselectivity Stereoselectivity Dane's diene Cyclobutenone Fosu, Evans Tia, Richard Adei, Evans Mechanistic studies on Diels-Alder [4þ2] cycloaddition reactions ofa,b-substituted cyclobutenones: Role of substituents in regio- andstereoselectivity |
| title | Mechanistic studies on Diels-Alder [4þ2] cycloaddition reactions ofa,b-substituted cyclobutenones: Role of substituents in regio- andstereoselectivity |
| title_full | Mechanistic studies on Diels-Alder [4þ2] cycloaddition reactions ofa,b-substituted cyclobutenones: Role of substituents in regio- andstereoselectivity |
| title_fullStr | Mechanistic studies on Diels-Alder [4þ2] cycloaddition reactions ofa,b-substituted cyclobutenones: Role of substituents in regio- andstereoselectivity |
| title_full_unstemmed | Mechanistic studies on Diels-Alder [4þ2] cycloaddition reactions ofa,b-substituted cyclobutenones: Role of substituents in regio- andstereoselectivity |
| title_short | Mechanistic studies on Diels-Alder [4þ2] cycloaddition reactions ofa,b-substituted cyclobutenones: Role of substituents in regio- andstereoselectivity |
| title_sort | mechanistic studies on diels alder 4th2 cycloaddition reactions ofa b substituted cyclobutenones role of substituents in regio andstereoselectivity |
| topic | Diels-Alder cycloaddition Mechanism Regioselectivity Stereoselectivity Dane's diene Cyclobutenone |
| url | https://ir.knust.edu.gh/handle/123456789/12650 |
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