Abstract:

Furanoheliangolides and eremantholides (figure 1) are natural sesquiterpene lactones that show a number of interesting biological activities, e.g. trypanocidal, anti-inflammatory, anti-tumor, etc. We have recently described a method for transforming furanoheliangolides (found in larger amounts in plants) into eremantholides using Stryker’s reagent. In this work we explore an interesting aspect regarding the stereochemistry of these compounds. There are no eremantholides, in nature, with relative stereochemistry cis between the substituent’s of positions C7 and C8. We have then decided to investigate if eremantholides could be prepared from cis substituted at C7 - C8 furanoheliangolides such as budlein A (2).