A novel method for the synthesis of a terpenoid, Mikanecic acid diesters from Baylis-Hillman adducts, (alkyl-3-hydroxy-2-methylenepropanoates by treatment with aldehyde react with various acrylates catalyzed by TiCl4) which on treatment with potassium carbonate led directly to the formation of Mikanecic acid diesters, through Diels-Alder type self-dimerization of 1,3-butadiene-2-carboxylate is reported using with potassium carbonate. The product is obtained in good yield.