((+OR-))-(alpha)-Eudesmol (1)* was synthesized in eleven steps from methyl farnesate (2) via the intramolecular 1,3-dipolar cycloaddition of E-monocyclofarnesal nitrone (3). The cycloaddition of this nitrone afforded two isoxazolidines 4 and 5 which differed only in their stereochemistry at C-2. The isomer distribution of the cycloaddition was controlled by the temperature at which the reaction was conducted; the ratio of 4 to 5 was 4:1 at 90(DEGREES) while the proportion of 5 increased at higher temperature. The transformation of 4 to 1 was accomplished stereospecifically by a four step reductive deamination sequence. Quaternization of 4 to 6 and ring expansion of 6 afforded tetrahydro-1,3-oxazine 7. Quaternization of 7 afforded methiodide 8 which underwent C-N bond cleavage by the hydrogenolysis to give 1. / The double bond isomer ((+OR-))-(beta)-eudesmol (8) was obtained when water was present in the quaternization reaction mixture of 7. This double bond isomerization was apparently initiated by a reversible deprotonation of the C-8 methyl group by the equatorial nitrogen on C-1. Alkylation rather than protonation of the allylic anion intermediate at C-7 resulted in 7-methyl-(beta)-eudesmol (9). / The synthesis of the three isomers of (alpha)-eudesmol as well as epi-(beta)- eudesmol (10) were realized from this approach. Epi-(alpha)-eudesmol(11) and the epi-(beta)- isomer 10 were obtained by the same reactionsequences from 5. The cycloaddition of Z-monocyclofarnesalnitrone (12) resulted in the formation of isoxazolidines 13 and 14which were each then converted to the respective eudesmol, epi- / cis-(alpha)-eudesmol (15) and cis-(alpha)-eudesmol (16). / *See abstract accompanying dissertation for the structures of the numbered compounds. / Source: Dissertation Abstracts International, Volume: 42-11, Section: B, page: 4433. / Thesis (Ph.D.)--The Florida State University, 1981.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_74701 |
| Contributors | WILLBRAND, ANN MARY., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 139 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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