A biomimetic synthesis of the taxane skeleton 4 (p. 5) was attempted. Lucas reagent catalyzed cationic cyclization of methyl geranylgeranate (20, p. 11) led to a mixture of compounds, none of which was isolated in pure enough form for definite indentification. Alternate synthetic approaches to the taxanes were investigated which involved the intermediacy of bicyclic enone 27 (p. 19); the latter was synthesized from dihydro-(beta)-ionone (26, p .19) in 26% yield by an initial Wittig reaction forming enamine 28 (p. 21) followed by condensation with ethyl vinyl ketone and cyclization to give 27 (p.19). Conversion of 27 to 4 required introduction of a one carbon unit. Hydrocyanation of 27 followed by allylic oxidation with CrO(,3)(.)2Pyr. and dehydrogenation with DDQ gave ketonitrile 49 (p. 29) as a mixture of all 4 isomers, in 24% yield from 27. Ketonitrile 49 was subjected to various reductive cyclization procedures which were unsuccessful. Dienone 37 (p. 24), nitroketone 38 (p. 24), p-nitrobenzoates 45 and 46 (p. 27), and ketoesters 75 and 76 (p. 37) were also subjected to anion forming conditions but did not cyclize. Stereochemical assignments of all compounds are discussed. / Source: Dissertation Abstracts International, Volume: 41-11, Section: B, page: 4117. / Thesis (Ph.D.)--The Florida State University, 1980.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_74356 |
| Contributors | CHAPMAN, ROBERT CLARK., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 112 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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