Total synthesis of (S)-(+)-imperanene. Effective use of regio- and enantioselective intramolecular carbon-hydrogen insertion reactions catalyzed by chiral dirhodium(II) carboxamidates

  • J Org Chem. 2002 May 3;67(9):2954-9. doi: 10.1021/jo016220s.
Michael P Doyle  1 ,  Wenhao Hu ,  Marcela V Valenzuela
Affiliations
  • 1. Department of Chemistry, University of Arizona, Tucson, Arizona 85721, USA. [email protected]
PMID: 11975552 DOI: 10.1021/jo016220s
Abstract

The total synthesis of (S)-(+)-imperanene, a natural product found in Chinese medicine, has been completed in 12 steps from a commercially available cinnamic acid. The key step is highly enantioselective carbon-hydrogen insertion from a diazoacetate using a chiral dirhodium(II) carboxamidate catalyst. An elimination process essential to the construction has been optimized to avoid intramolecular Friedel-Crafts alkylation.

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