On a new synthesis of sterpurene and the bioactivity of some related Chondrostereum purpureum sesquiterpene metabolites

  • 10.1139/v97-090
  • Canadian Journal of Chemistry
  • p 742-753, Volume 75, Issue 6,
  • journal-article
Sterpurene, a sesquiterpene hydrocarbon metabolite of Chondrostereumpurpureum, a plant pathogen and potential mycoherbicide, was synthesized by a six-step sequence, in 33% overall yield. The key steps were a thermal [4 + 2] (Diels–Alder) cycloaddition of a ketene acetal diene with a conjugated ester dienophile, and a remarkably stereoselective [2 + 2] photocycloaddition of ethylene with the resulting conjugated ketone. Several related, more highly oxygenated, metabolites isolated from culture filtrates of C. purpureum (cf. Ayer) were tested for toxicity to cells of a hybrid aspen, Populusdeltoides X nigra. Their phytotoxicity, at concentrations as low as 10 ppm, suggests that, like the endo-polygalacturonase produced by the fungus, these sesquiterpenes may be partially responsible for the foliar lesions associated with infection of deciduous species by the pathogen. Keywords: Chondrostereumpurpureum, mycoherbicide, metabolites, sterpurenes, synthesis, Diels–Alder, photocycloaddition, pyramidalization, phytotoxicity.


Reliable procedure but modifications helpful

The article by Strunz and co-workers reported a total synthesis of sterpurene and the bioactivity of some related sesquiterpene metabolites.

I am particularly interested in the preparation of intermediate 14 (4-step synthesis, Scheme 3) since it could serve as a building...