Phytochemicals from Echinacea and Hypericum: A Direct Synthesis of Isoligularone

Abstract

Reaction of trienes with α,β‐unsaturated aldehydes produces bicyclic products via a tandem Diels–Alder/ene reaction. The adduct from tiglic aldehyde was converted into isoligularone by conversion to a furan followed by benzylic oxidation.

Keywords:

• Diels–Alder
• ene reaction
• oxidation

Acknowledgment

We thank the National Institutes of Health (Grant P01 ES12020) and the Office of Dietary Supplements for partial financial support through the Center for Research on Botanical Dietary Supplements at Iowa State University.