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Cycloaddition-fragmentation mediated pathways to ring D modified 19-norsteroids
Includes summary.
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| Other Authors: | |
| Format: | Thesis |
| Language: | English |
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Department of Chemistry
2016
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| _version_ | 1867614010939015168 |
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| access_status_str | Open Access |
| author | Sickle, Eugene Stanford |
| author2 | Bull, James R |
| author_browse | Bull, James R Sickle, Eugene Stanford |
| author_facet | Bull, James R Sickle, Eugene Stanford |
| author_sort | Sickle, Eugene Stanford |
| collection | Thesis |
| description | Includes summary. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/17967 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:45:15.193Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| 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:11427/17967 Cycloaddition-fragmentation mediated pathways to ring D modified 19-norsteroids Sickle, Eugene Stanford Bull, James R Chemistry Includes summary. Includes bibliographical references. An efficient strategy for the synthesis of 14β-3'-oxobutyl 19-norsteroids has been developed and the intramolecular reactivity of the derived compounds has been investigated. The approach is based on cycloaddition of methyl vinyl ketone to 3-methoxyestra-1,3,5(10),14,16-pentaen-17-yl acetate which proceeded with a high degree of regio- and stereoselectivity to give 16α-acetyl-3-methoxy-14, 17α-ethenoestra-1 ,3,5(1 O)-trien-17β-yl acetate. The cycloadduct underwent base mediated fragmentation, affording an efficient and stereocontrolled synthesis of 3-methoxy-14β-3'-oxobutylestra-1,3,5(10),15-tetraen-17-one which in turn gave 3-methoxy-5',6'-dihydro-15αH-benzo[14,15]-14β-estra-1,3,5(1O)-trien-4'(3'H), 17-dione via an intramolecular Michael reaction. Regioselective deoxygenation of the dione at C-4', followed by standard functional group modifications provided the parent 14β-perhydrobenzo[14,15]-estradiol analogues. An alternative, more expedient, route to this novel steroidal ring system was developed which relied on an anionic oxy-Cope rearrangement as the key step. Thus methylenation of the cycloadducts derived from reaction of the dienyl acetate and selected dienophiles (acrolein and methyl vinyl ketone) gave after hydrolysis of the bridgehead ester, substrates which underwent [3,3]sigmatropic rearrangement to generate a series of 14β-perhydrobenzo[14,15]-17-ketones. 2016-03-17T12:46:07Z 2016-03-17T12:46:07Z 1997 Doctoral Thesis Doctoral PhD http://hdl.handle.net/11427/17967 eng application/pdf Department of Chemistry Faculty of Science University of Cape Town |
| spellingShingle | Chemistry Sickle, Eugene Stanford Cycloaddition-fragmentation mediated pathways to ring D modified 19-norsteroids |
| thesis_degree_str | Doctoral |
| title | Cycloaddition-fragmentation mediated pathways to ring D modified 19-norsteroids |
| title_full | Cycloaddition-fragmentation mediated pathways to ring D modified 19-norsteroids |
| title_fullStr | Cycloaddition-fragmentation mediated pathways to ring D modified 19-norsteroids |
| title_full_unstemmed | Cycloaddition-fragmentation mediated pathways to ring D modified 19-norsteroids |
| title_short | Cycloaddition-fragmentation mediated pathways to ring D modified 19-norsteroids |
| title_sort | cycloaddition fragmentation mediated pathways to ring d modified 19 norsteroids |
| topic | Chemistry |
| url | http://hdl.handle.net/11427/17967 |
| work_keys_str_mv | AT sickleeugenestanford cycloadditionfragmentationmediatedpathwaystoringdmodified19norsteroids |