Carbonylation of Vinyl Aromatics: Convenient Regioselective Synthesis of 2-Arylpropanoic Acids

Various substituted and nonsubstituted 2-arylpropanoic acids have been synthesized in high turnovers with high regioselectivity by palladium-catalyzed carbonylation of vinyl aromatics. Both terminal and internal olefins are carbonylated, though hindered olefins are less reactive. In all the cases high yields and high selectivity are observed. Olefins with electron-withdrawing para substituents gave the highest regioselectivity in the formation of the corresponding 2-arylpropanoic acids.