Eremolactone from Eremophila freelingii

An acetylenic 4-ylidenebutenolide of a quite different constitution is freelingyne (33). This highly unsaturated furano-sesquiterpene is found in the heartwood of the Australian shrub Eremophila freelingii, and it was the first acetylenic terpenoid to be isolated (55). Dihydrofreelingyne (34) has also been isolated from E. freelingii (36) and the unusual diterpenoid eremolactone (35) occurs in the leaves of the same species (37). The complete stereochemistry of freelingyne has been established by direct X-ray methods (38). 

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