A palladium catalyzed efficient synthesis of γ-methylene-α,β-unsaturated γ-lactones via cyclization of 3,4-alkadienoic acids

An efficient method was developed for the synthesis of γ-methylene-α,β-unsaturated γ-lactones from the Pd-catalyzed cyclization of 3,4-alkadienoic acids. Control experiment shows that the reaction should be carried out under a N2 atmosphere to ensure the high purity of the products.