Synthesis of 3-Arylpropenal and 3-Arylpropionic Acids by Palladium Catalysed Heck Coupling Reactions: Scopes and Limitations

Several classical methods were described for the selective synthesis of cinnamaldehyde derivatives and 3-arylpropionic acids but their applicability remains limited due to the difficult and costly synthesis of the starting materials. Since few years, palladium catalyzed procedure has been reported. Whatever they use homogeneous or heterogeneous palladium catalysts, these catalytic methods offer viable environmental friendly alternatives to stoechiometric methods particularly since they generally required a single reaction step starting from simple substrates. Some of these new methods are really considered as green alternatives since they use heterogeneous easily separable (and recyclable) palladium catalysts.