Stereoselective Synthesis of (–)-Heliannuol E
Narihito Ogawa reports on the synthesis of (–)-heliannuol E by selective propargyl substitution.
Stereoselective Synthesis of (–)-Heliannuol E by α-Selective Propargyl Substitution: N. Ogawa, C. Uematsu, Y. Kobayashi
Synlett 2021, 32, DOI: 10.1055/s-0040-1719844
(–)-Heliannuol E is one of 13 heliannuol sesquiterpenoids isolated to date from the common sunflower Helianthus annuus. These compounds are biologically interesting as they show allelopathy, for example, they can suppress or eliminate competing plant species near native plants. Furthermore, their intriguing chemical structure has attracted further interest from organic chemists. For these reasons, several syntheses of (–)-heliannuol E have been described but there is still significant room for improvement in terms of overall efficiency and potential for scale-up. In this context, the group of Professor Narihito Ogawa from Meiji University (Kanagawa, Japan) recently described a novel strategy to access the title compound.
Professor Ogawa said: “We achieved the stereoselective synthesis of (–)-heliannuol E by α-selective propargyl substitution. We have demonstrated that the propargyl substitution is a useful reaction in the synthesis of (–)-helianuol E. In the future, we will use this reaction in the synthesis of natural products.”