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Synfacts 2016; 12(08): 0767
DOI: 10.1055/s-0035-1562705
Synthesis of Natural Products and Potential Drugs
© Georg Thieme Verlag Stuttgart · New York

Total Synthesis of (−)-6-epi-Ophiobolin N

Authors

    Contributor(s):

  • Erick M. Carreira

  • Johannes Boshkow

Brill ZG, Grover HK, Maimone TJ * University of California, Berkeley, USA
Enantioselective Synthesis of an Ophiobolin Sesterterpene via a Programmed Radical Cascade.

Science 2016;
352: 1078-1082
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Further Information

Publication History

Publication Date:
19 July 2016 (online)

 
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Key words

(−)-6-epi-ophiobolin N - sesterterpene - radical cascade cyclization

Significance

The ophiobolin family of sesterpenes is characterized by a fused 5-8-5 ring system. Brill, Grover, and Maimone developed a radical cascade cyclization to assemble this ring system, culminating in the total synthesis of (−)-6-epi-ophiobolin N. The complete synthesis is remarkably short for a sesterterpene, merely requiring nine linear steps.


Comment

Commencing from farnesol, cyclization precursor 5 could be accessed in four steps. The central radical cascade gave the fused carbon skeleton of the target molecule in 56% yield. ­TADDOL-derived thiol 6 was found to be crucial to favor the correct stereochemistry at C15. The natural product was obtained after four additional steps.





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