An efficient construction of bicyclic systems containing a seven-membered ring by tandem ring-closing metathesis reactions of dienynes

Abstract : Various (5-7) and (6-7) bicyclic dienes bearing quaternary methyl group and ester functionality have been synthesized from acyclic dienynes by tandem ring-closing metathesis (RCM) reaction. Epoxidation of these conjugated dienes led to bicyclic vinyl oxiranes which undergo acid-catalyzed addition of alcohols to afford highly oxygenated compounds. © 2006 Elsevier B.V. All rights reserved.