First ketene cycloaddition approach to (±)-junionone

Junionone is the first monocyclic cyclobutane monoterpenoid isolated from a plant. Of the existing four syntheses of this compound, none employs a ketene cycloaddition to construct the four-membered ring. Herein, we report the first total synthesis of junionone that features a ketene cycloaddition for the synthesis of this compound, starting from the commercially available 1,5-hexadiene. (C) 2015 Elsevier Ltd. All rights reserved.