Merrilliadione – a Rare Isopropyl (13→11)‐abeo‐9,11‐seco Abietane Diterpene from Illicium merrillianum

Merrilliadione (1), a new diterpene with a unique isopropyl (1311)-abeo-9,11-seco-abietane skeleton, and two new abietane diterpenoids (2 and 3) were isolated from Illicium merrillianum. This is the first report of an isopropyl (1311)-abeo-9,11-seco abietane diterpenoid. The structures of 1–3 were established by comprehensive spectroscopic analysis, single-crystal X-ray diffraction, and quantum chemical computation of electronic circular dichroism (ECD) spectra.