| Autor: |
Perales JB; Department of Chemistry, University of California, Irvine, California 92697-2025, USA., Makino NF, Van Vranken DL |
| Jazyk: |
angličtina |
| Zdroj: |
The Journal of organic chemistry [J Org Chem] 2002 Sep 20; Vol. 67 (19), pp. 6711-7. |
| DOI: |
10.1021/jo0259459 |
| Abstrakt: |
The iron-catalyzed Kirmse reaction was used to generate neopentyl alpha-silyl thioethers that were elaborated to meroterpenes using two complementary routes: one route involved a sila-Pummerer rearrangement, and the other route involved a Peterson olefination. While severe eclipsing interactions undermined the efficiency of the stereospecific sila-Pummerer rearrangement, they made it possible to stereoselectively generate E olefins without isolation or separation of syn- and anti-beta-silyl alkoxides. Addition of a neopentyl alpha-silyl alkyllithium intermediate to an aryl aldehyde generated a mixture of syn- and anti-beta-silyl alkoxides. The syn-beta-silyl alkoxide eliminated stereospecifically at -78 degrees C to give an E olefin, whereas the anti-beta-silyl alkoxide was unreactive. The reaction mixture was then acidified and heated to induce stereospecific elimination of the anti isomer to give the same E olefin via a complementary cationic pathway. This route was used to complete the first synthesis of the meroterpene (+/-)-3-hydroxybakuchiol. In addition, we synthesized another meroterpene corresponding to the natural product corylifolin and offer evidence that the structure of corylifolin was misassigned. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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