A method of synthesis of para-substituted benzoate esters and acids is provided, wherein the para-substituted regioisomer is obtained substantially free of the meta-substituted impurity, the method comprising contacting a coumalate ester or acid and an unactivated alkene at elevated temperature in the presence of a metal oxidation catalyst and an oxidant. The metal oxidation catalyst can be palladium, such as palladium on carbon, and the oxidant can be the oxygen gas in ambient air. The reaction can be carried out without solvent or in high boiling hydrocarbon solvents such as mesitylene. When the unactivated alkene is a monosubstituted alkene, yields of at least about 50 or 60% of para-substituted ester and acid products, respectively, are obtained, substantially free of the regioisomeric meta-substituted impurity.