Patent ID: 7265242

Claim:
A process for the carbonylation of unsaturated compounds by contacting the unsaturated compound with carbon monoxide in the presence of a catalyst system comprising: (a) a source of palladium and/or platinum; and (b) an unsymmetrical bidentate diphosphine ligand of formula I, R 1 R 2 >P 1 —R 3 —P 2 <R 4 R 5 (I) wherein P 1 and P 2 represent phosphorus atoms; R 3 represents a divalent organic bridging group; and R 1 , R 2 , R 4 and R 5 each individually, or R 1 and R 2 jointly, and/or R 4 and R 5 jointly represent organic groups that are covalently linked to the phosphorus; and wherein R 1 , R 2 , R 4 and R 5 are chosen in such way, that the phosphino group R 1 R 2 >P 1 differs from the phosphino group P 2 <R 4 R 5 .