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

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.