Isolation and Synthesis of Novel Meroterpenoids from Rhodomyrtus tomentosa: Investigation of a Reactive Enetrione Intermediate

Rhodomyrtusials A–C (5–7), the first examples of triketone‐sesquiterpene meroterpenoids featuring a unique 6/5/5/9/4 fused pentacyclic ring system were isolated from Rhodomyrtus tomentosa, along with several biogenetically‐related dihydropyran isomers (8–11). Compounds 5, 6, and 10 showed acetylcholinesterase (AChE) inhibitory activity. Structures of the isolates were unambiguously established by a combination of spectroscopic data, ECD analysis, and total synthesis. Bioinspired total syntheses of 5, 7, and 8–11 were achieved in six steps utilizing a reactive enetrione intermediate generated in situ from a readily available hydroxy‐endoperoxide precursor.

from A via a.sfakia on Inoreader http://bit.ly/2Hxh5jP