The palladium-catalyzed, atmospheric-pressure carboxylation of allylic halides occurs readily in an aqueous sodium hydroxide/organic solvents two-phase system, giving ß,?-unsaturated acids. Phosphine complexes [PdCl2L2] (I, L = m-(Ph2P)C6H4SO3Na; II, L = Ph3P) or Na2[PdCl4] (III) can be used as the catalyst. Atmospheric-pressure alkoxycarbonylation is realized under the influence of a homogeneous alcoholic solution of sodium alkoxide. Phosphine-free palladium complexes, such as [(p-allyl)PdCl]2or III, are the favored catalyst. ß,?-Unsaturated esters are obtained in high yields.