the present invention relates to a process for the preparation of a carboxylic acid ester of the general formula ii , wherein r is alkyl or aryl , r 1 is aryl , substituted aryl , naphthyl or substituted naphthyl or alkyl , r 2 , r 3 , r 4 and r 5 are independently hydrogen or alkyl by reacting an olefin of the general formula i wherein , r 1 is aryl , substituted aryl , naphthyl or substituted naphthyl or alkyl , r 2 , r 3 , and r 4 are independently hydrogen or alkyl , in the presence of an alcohol and an organic solvent and a supported aqueous phase palladium complex catalyst , in presence or absence of a protonic acid and an alkali metal halide , under carbon monoxide atmosphere , cooling the reaction mixture to ambient temperature , depressurising the reactor , flushing the reaction vessel with inert gas , separating the catalyst by filtration and removing the solvent and isolating the compound of formula ii .