Total synthesis of (-)-heptemerone B and (-)-guanacastepene E

Aubry K. Miller, Chambers C. Hughes, Joshua J. Kennedy-Smith, Stefan N. Gradl, Dirk Trauner

Research output: Contribution to journalArticlepeer-review


A concise, stereoselective, and convergent total synthesis of the unnatural enantiomer of the neodolastane diterpenoid heptemerone B has been completed. Saponification of (-)-heptemerone afforded (-)-guanacastepene E. The absolute stereochemistry of (-)-heptemerone B was thus established as 5-(S), the same as (-)-guanacastepene E. The longest linear sequence of the synthesis comprises 17 (18) steps from simple known starting materials. Our general synthetic approach integrates a diverse set of reactions, including an intramolecular Heck reaction to create one quaternary stereocenter and a cuprate conjugate addition for the establishment of the other. The central seven-membered ring was closed with an uncommon electrochemical oxidation, whereas the five-membered ring was formed through ring-closing metathesis. The absolute configuration of the two key building blocks was established through an asymmetric reduction and an asymmetric ene reaction.

Original languageEnglish (US)
Pages (from-to)17057-17062
Number of pages6
JournalJournal of the American Chemical Society
Issue number51
StatePublished - Dec 27 2006

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry


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