(E)‐9‐Isopropyl‐6‐methyl‐5,9‐decadien‐2‐one, a Terpenoid C14‐Ketone with a Novel Skeleton

Abstract
(E)‐9‐Isopropyl‐6‐methyl‐5,9‐decadien‐2‐one (1a), a terpenoid C14‐ketone with a novel skeleton, was isolated from costus root oil (Saussurea lappa CLARKE) and its structure established by a two‐step synthesis from thuja ketone (2). The possible role of the new compound as an intermediate in the biosynthesis of the irones is discussed.