Palladium-catalyzed hydroesterification of styrene derivatives in the presence of ionic liquids

The palladium-catalyzed hydroesterification of olefins occurs efficiently in a range of ionic liquid media. Selectivities ranging from 5–7:1 for the linear ester were obtained with styrene in a range of IL solvents. The use of ILs allowed the catalyst to be easily separated from the organic product by either extraction or distillation. The (Ph3P)2PdCl2 precatalyst could be recovered unchanged from the ionic liquid phase. The IL/catalyst phase could be recycled five times with an average yield of 68%.