Guaianolide

In organic chemistry, a guaianolide is a type of sesquiterpene lactone consisting of a gamma-lactone and either a cyclopentane or cyclopentene, both fused to a central cycloheptane or cycloheptene structure. There are two subclasses, structural isomers differing in the location that part of the lactone is bonded to the central ring, known as 6,12-guaianolides and 8,12-guaianolides.^[1]

Because some of the natural products in this class of tricyclic phytochemical have been found to be potentially biologically active, there has been interest in their chemical syntheses.^[2] The full biosynthetic origin of most of the known guaianolides has not been established, but the pathway is generally presumed to begin with the formation of a germacrene lactone derived from farnesyl pyrophosphate.^[1]