Multigram Synthesis of the C29−C51 Subunit and Completion of the Total Synthesis of Altohyrtin C (Spongistatin 2)
| Autor: | Grier A. Wallace, Clayton H. Heathcock, Michele M Claffey, Christopher J. Hayes, Mark L. McLaughlin, Jed L. Hubbs, J. R. Medina, Robert W. J. Scott, Gregory R. Ott |
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| Rok vydání: | 2003 |
| Předmět: | |
| Zdroj: | Journal of the American Chemical Society. 125:12844-12849 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/ja030317+ |
| Popis: | A multigram synthesis of the C29−C51 subunit of altohyrtin C (spongistatin 2) has been accomplished. Union of this intermediate with the C1−C28 fragment and further elaboration furnished the natural product. Completion of the C29−C51 subunit began with the aldol coupling of the boron enolate derived from methyl ketone 8 and aldehyde 9. Acid-catalyzed deprotection/cyclization of the resulting diastereomeric mixture of addition products was conducted in a single operation to afford the E-ring of altohyrtin C. The diastereomer obtained through cyclization of the unwanted aldol product was subjected to an oxidation/reduction sequence to rectify the C35 stereocenter. The C45−C48 segment of the eventual triene side chain was introduced by addition of a functionalized Grignard reagent derived from (R)-glycidol to a C44 aldehyde. Palladium-mediated deoxygenation of the resulting allylic alcohol was followed by adjustment of protecting groups to provide reactivity suitable for the later stages of the synthesis. Th... |
| Databáze: | OpenAIRE |
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