Facile Total Syntheses of Putative and Revised Structures of Pethybrene

Abstract The structural identity of pethybrene was confirmed as theoretically proposed 6‐5‐5 tricyclic structure through total syntheses of two putative structures. The originally proposed structure 1 was synthesized in 13 steps via Intramolecular Pauson‐Khand reaction to form the triquinane skeleton and the newly proposed structure from a theoretical study 2 was obtained from a known [2+2] cycloaddition product in 3 steps.