A vinyl ester alkoxycarbonylation process comprising reacting a vinyl ester with carbon monoxide in the presence of an alkanol and a catalyst system. The catalyst system used is obtainable by combining: a) a metal of Group VIII B or a compound thereof, and b) a bidentate ligand of general formula (I) R is a covalent bridging group; R1 together with Q2 to which form an optionally substituted 2-Q2-tricyclo[3.3.1.1{3,7}]decyl group or derivative thereof (2-PA); R2 and R3 independently represent univalent radicals up to 20 atoms or jointly form a bivalent radical of up to 20 atoms; and Q1 and Q2 each independently represent phosphorous, arsenic or antimony. The process is carried out for the production of a 3-hydroxy propanoate ester or acid of formula (II) CH2(OH)CH2C(O)OR28  (II). or for the production of a lactate ester or acid of formula III.