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Total Synthesis of Zoanthamine Alkaloids

Total Synthesis of Zoanthamine Alkaloids. 郭蕊 2012.03.31. Miyashita, M., et al. Acc. Chem. Res. , 2012 , ASAP. Stoltz, B.M., et al. Angew. Chem. Int. Ed. 2008 , 47 , 2365. Natural Products Isolated from the Zoanthids. PGA2. Zoanthoxanthin. Zoanthoxanthin.

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Total Synthesis of Zoanthamine Alkaloids

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  1. Total Synthesis of Zoanthamine Alkaloids 郭蕊 2012.03.31 Miyashita, M., et al. Acc. Chem. Res., 2012, ASAP. Stoltz, B.M., et al.Angew. Chem. Int. Ed.2008, 47, 2365

  2. Natural Products Isolated from the Zoanthids PGA2 Zoanthoxanthin Zoanthoxanthin

  3. Zoanthamine Alkaloids: Isolation and Biological Activity Zoanthamine: Isolation: Rao and Faulker, 1984 off the coast of India Biological activity: Inhibits ear inflammation in mice Norzoanthamine: Isolation: Uemura, 1995 from the coast of islands south of Japan Biological activity: Prevents osteoporosis in vivo in ovarieoctimized mice Cytoxicity against P388 murine leucemia cells Inhibits human platelet aggregation Zoanthenol: Isolation: Norte, 1996 in the Canary Islands Biological activity: Inhibits human platelet aggregation Rao, C. B.; Faulkner, D. J., et al. J. Am. Chem. Soc.1984, 106, 7983. Uemura, D., et al. Heterocycl. Commun. 1995, 1, 207 Norte, M., et al. Tetrahedron,1999, 55, 5539.

  4. Synthetic Efforts Towards Norzoanthamine Total synthesis: • Miyashita, Norzoanthamine-2004 Partial synthesis: • Tanner • Williams • Uemura • Stoltz • Theodorakis • Kobayashi Miyashita, M., et al. Science, 2004, 305, 495.

  5. Retrosynthetic Analysis of Norzoanthamine 41 steps, 3.5% overall yield (average of 92% yield per step) • Key steps: • IMDA to set stereochemistry of the BC rings • Use of kinetic isotope effect for installation of alkyne • Bis-aminoacetalization for the construction of the DEFG rings

  6. Synthesis of the ABC Ring System

  7. Chugaev Elimination

  8. Hydrosilylation reaction in the presence of Wilkinson’s catalyst Ojima I., et al. Organometallics, 1982, 1, 1390 Katsumura protocol Katsumura K., et al. Tetrahedron Lett.1985, 38, 4625

  9. Key Intramolecular Diels-Alder Reaction

  10. Methylation

  11. Trost protocol Trost B. M., et al. Tetrahedron Lett.1984, 25, 173

  12. The Kinetic Isotope Effect

  13. Construction of the DEFG Rings

  14. Ito-Saegusa method Ito Y., Hirao T., Saegusa T., J. Org. Chem.1978, 43, 1011

  15. Completion of Norzoanthamine

  16. Total Synthesis of Zoanthamine Miyashita, M., et al. Chem.Eur. J. 2009, 15, 6626

  17. Total Synthesis of Zoanthenol Miyashita, M., et al. Chem. Asian J. 2011, 6, 922 Miyashita, M., et al. Angew. Chem., Int. Ed. 2009, 48, 8905

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