Studies on the Enantioselective Synthesis of <i>E</i>-Ethylidene-bearing Spiro[indolizidine-1,3′-oxindole] Alkaloids
A synthetic route for the enantioselective construction of the tetracyclic spiro[indolizidine-1,3′-oxindole] framework present in a large number of oxindole alkaloids, with a <i>cis</i> H-3/H-15 stereochemistry, a functionalized two-carbon substituent at C-15, and an <i>E</i>...
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| Format: | Article |
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MDPI AG
2021-01-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/26/2/428 |
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| author | Nihan Yayik Maria Pérez Elies Molins Joan Bosch Mercedes Amat |
| author_facet | Nihan Yayik Maria Pérez Elies Molins Joan Bosch Mercedes Amat |
| author_sort | Nihan Yayik |
| collection | DOAJ |
| description | A synthetic route for the enantioselective construction of the tetracyclic spiro[indolizidine-1,3′-oxindole] framework present in a large number of oxindole alkaloids, with a <i>cis</i> H-3/H-15 stereochemistry, a functionalized two-carbon substituent at C-15, and an <i>E</i>-ethylidene substituent at C-20, is reported. The key steps of the synthesis are the generation of the tetracyclic spirooxindole ring system by stereoselective spirocyclization from a tryptophanol-derived oxazolopiperidone lactam, the removal of the hydroxymethyl group, and the stereoselective introduction of the <i>E</i>-ethylidene substituent by acetylation at the α-position of the lactam carbonyl, followed by hydride reduction and elimination. Following this route, the 21-oxo derivative of the enantiomer of the alkaloid 7(<i>S</i>)-geissoschizol oxindole has been prepared. |
| first_indexed | 2024-03-09T04:40:54Z |
| format | Article |
| id | doaj.art-544ba2fdf6a64992a640ff7ee68ad575 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-09T04:40:54Z |
| publishDate | 2021-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-544ba2fdf6a64992a640ff7ee68ad5752023-12-03T13:21:15ZengMDPI AGMolecules1420-30492021-01-0126242810.3390/molecules26020428Studies on the Enantioselective Synthesis of <i>E</i>-Ethylidene-bearing Spiro[indolizidine-1,3′-oxindole] AlkaloidsNihan Yayik0Maria Pérez1Elies Molins2Joan Bosch3Mercedes Amat4Laboratory of Organic Chemistry, Faculty of Pharmacy and Food Sciences, and Institute of Biomedicine (IBUB), University of Barcelona, 08028 Barcelona, SpainDepartment of Nutrition, Food Sciences and Gastronomy, Faculty of Pharmacy and Food Sciences, and Institute of Nutrition and Food Safety (INSA-UB), University of Barcelona, 08921 Santa Coloma de Gramanet, SpainInstitut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Cerdanyola, SpainLaboratory of Organic Chemistry, Faculty of Pharmacy and Food Sciences, and Institute of Biomedicine (IBUB), University of Barcelona, 08028 Barcelona, SpainLaboratory of Organic Chemistry, Faculty of Pharmacy and Food Sciences, and Institute of Biomedicine (IBUB), University of Barcelona, 08028 Barcelona, SpainA synthetic route for the enantioselective construction of the tetracyclic spiro[indolizidine-1,3′-oxindole] framework present in a large number of oxindole alkaloids, with a <i>cis</i> H-3/H-15 stereochemistry, a functionalized two-carbon substituent at C-15, and an <i>E</i>-ethylidene substituent at C-20, is reported. The key steps of the synthesis are the generation of the tetracyclic spirooxindole ring system by stereoselective spirocyclization from a tryptophanol-derived oxazolopiperidone lactam, the removal of the hydroxymethyl group, and the stereoselective introduction of the <i>E</i>-ethylidene substituent by acetylation at the α-position of the lactam carbonyl, followed by hydride reduction and elimination. Following this route, the 21-oxo derivative of the enantiomer of the alkaloid 7(<i>S</i>)-geissoschizol oxindole has been prepared.https://www.mdpi.com/1420-3049/26/2/428oxindolesalkaloidsspiro compoundsethylidene |
| spellingShingle | Nihan Yayik Maria Pérez Elies Molins Joan Bosch Mercedes Amat Studies on the Enantioselective Synthesis of <i>E</i>-Ethylidene-bearing Spiro[indolizidine-1,3′-oxindole] Alkaloids Molecules oxindoles alkaloids spiro compounds ethylidene |
| title | Studies on the Enantioselective Synthesis of <i>E</i>-Ethylidene-bearing Spiro[indolizidine-1,3′-oxindole] Alkaloids |
| title_full | Studies on the Enantioselective Synthesis of <i>E</i>-Ethylidene-bearing Spiro[indolizidine-1,3′-oxindole] Alkaloids |
| title_fullStr | Studies on the Enantioselective Synthesis of <i>E</i>-Ethylidene-bearing Spiro[indolizidine-1,3′-oxindole] Alkaloids |
| title_full_unstemmed | Studies on the Enantioselective Synthesis of <i>E</i>-Ethylidene-bearing Spiro[indolizidine-1,3′-oxindole] Alkaloids |
| title_short | Studies on the Enantioselective Synthesis of <i>E</i>-Ethylidene-bearing Spiro[indolizidine-1,3′-oxindole] Alkaloids |
| title_sort | studies on the enantioselective synthesis of i e i ethylidene bearing spiro indolizidine 1 3 oxindole alkaloids |
| topic | oxindoles alkaloids spiro compounds ethylidene |
| url | https://www.mdpi.com/1420-3049/26/2/428 |
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