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Chiral acyl radicals generated by visible light enable stereoselective access to 3,3-disubstituted oxindoles: application toward the synthesis of (–)- and (+)-physovenine
Radical species serve as powerful tools for carbon-carbon bond formation in synthetic organic chemistry. Such species can be formed in an efficient and environmentally friendly manner by way of photoredox catalysis, which uses a photocatalyst in conjunction with visible light (typically) to generate...
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| Format: | Thesis |
| Language: | English |
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Department of Chemistry
2025
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| _version_ | 1867613210757038080 |
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| access_status_str | Open Access |
| author | Späth, Josef |
| author2 | Petersen, Wade |
| author_browse | Petersen, Wade Späth, Josef |
| author_facet | Petersen, Wade Späth, Josef |
| author_sort | Späth, Josef |
| collection | Thesis |
| description | Radical species serve as powerful tools for carbon-carbon bond formation in synthetic organic chemistry. Such species can be formed in an efficient and environmentally friendly manner by way of photoredox catalysis, which uses a photocatalyst in conjunction with visible light (typically) to generate the necessary environment for radical generation under extremely mild conditions. This work outlines the development of a novel imidazolidinone-derived acyl radical, generated under photoredox catalysis, and its application toward the stereoselective synthesis of 3,3- disubstituted oxindoles via an additional-cyclisation cascade sequence to acrylamide precursors. 6 oxindoles were produced in up to 85% yield, with moderate diastereoselectivity of up to 2.2:1, but which could be easily separated by standard chromatography to yield pure diastereomers. Mechanistic studies, by virtue of TEMPO-trapping experiments provided strong support for the existence of the proposed acyl-radical, and further synthetic utility of the research was demonstrated in formal synthesis of the natural product (–)-physovenine, a member of the biologically active cyclotryptamine alkaloids. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/41366 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:31.718Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Department of Chemistry |
| publisherStr | Department of Chemistry |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/41366 Chiral acyl radicals generated by visible light enable stereoselective access to 3,3-disubstituted oxindoles: application toward the synthesis of (–)- and (+)-physovenine Späth, Josef Petersen, Wade Hunter, Roger chemistry Radical species serve as powerful tools for carbon-carbon bond formation in synthetic organic chemistry. Such species can be formed in an efficient and environmentally friendly manner by way of photoredox catalysis, which uses a photocatalyst in conjunction with visible light (typically) to generate the necessary environment for radical generation under extremely mild conditions. This work outlines the development of a novel imidazolidinone-derived acyl radical, generated under photoredox catalysis, and its application toward the stereoselective synthesis of 3,3- disubstituted oxindoles via an additional-cyclisation cascade sequence to acrylamide precursors. 6 oxindoles were produced in up to 85% yield, with moderate diastereoselectivity of up to 2.2:1, but which could be easily separated by standard chromatography to yield pure diastereomers. Mechanistic studies, by virtue of TEMPO-trapping experiments provided strong support for the existence of the proposed acyl-radical, and further synthetic utility of the research was demonstrated in formal synthesis of the natural product (–)-physovenine, a member of the biologically active cyclotryptamine alkaloids. 2025-04-08T11:25:58Z 2025-04-08T11:25:58Z 2024 2025-04-07T08:18:55Z Thesis / Dissertation Masters MSc http://hdl.handle.net/11427/41366 eng application/pdf Department of Chemistry Faculty of Science |
| spellingShingle | chemistry Späth, Josef Chiral acyl radicals generated by visible light enable stereoselective access to 3,3-disubstituted oxindoles: application toward the synthesis of (–)- and (+)-physovenine |
| thesis_degree_str | Master's |
| title | Chiral acyl radicals generated by visible light enable stereoselective access to 3,3-disubstituted oxindoles: application toward the synthesis of (–)- and (+)-physovenine |
| title_full | Chiral acyl radicals generated by visible light enable stereoselective access to 3,3-disubstituted oxindoles: application toward the synthesis of (–)- and (+)-physovenine |
| title_fullStr | Chiral acyl radicals generated by visible light enable stereoselective access to 3,3-disubstituted oxindoles: application toward the synthesis of (–)- and (+)-physovenine |
| title_full_unstemmed | Chiral acyl radicals generated by visible light enable stereoselective access to 3,3-disubstituted oxindoles: application toward the synthesis of (–)- and (+)-physovenine |
| title_short | Chiral acyl radicals generated by visible light enable stereoselective access to 3,3-disubstituted oxindoles: application toward the synthesis of (–)- and (+)-physovenine |
| title_sort | chiral acyl radicals generated by visible light enable stereoselective access to 3 3 disubstituted oxindoles application toward the synthesis of and physovenine |
| topic | chemistry |
| url | http://hdl.handle.net/11427/41366 |
| work_keys_str_mv | AT spathjosef chiralacylradicalsgeneratedbyvisiblelightenablestereoselectiveaccessto33disubstitutedoxindolesapplicationtowardthesynthesisofandphysovenine |