Highly efficient catalyst system for the synthesis of 2-arylpropionic acids by carbonylation

Carbonylation of 1-(4-isobutylphenyl)ethanol has been studied using a homogeneous catalyst system consisting of PdCl2(PPh3)2/ TsOH/ LiCl. Higher reaction rates with TOF up to 1200 h-1 and ibuprofen selectivity >95% have been achieved at 388 K under a CO partial pressure of 5.4 MPa. The reaction proceeds through the formation of 4-isobutylstyrene and 1-(4-isobutylphenyl)ethyl chloride as intermediates. The same catalyst system is shown to be effective for carbonylation of various a-arylethanols, vinyl aromatics and corresponding chloro derivatives