The Heck Reaction and Cinnamic Acid Synthesis by Heterogeneous Catalysis

The Heck reaction for the construction of carbon-carbon bonds, using palladium catalysts, is one of the most valuable strategies in organic chemistry and appears frequently in the literature, usually as homogeneous catalysis. In this review the progress made to date with this reaction is examined, together with the most discussed aspects of the Heck reaction, including a description of its mechanism and the conditions required for success. Some limitations to the homogeneous reaction are mentioned with reasons for proceeding with heterogeneous catalysts, in particular with palladium/carbon. Examples of various heterogeneous Heck reactions are presented and work that we are undertaking to develop methods for the production of cinnamic acids, useful as substrates for the synthesis of “unnatural” amino acids, is discussed. Finally, we present some results from our work using palladium/carbon catalysts for heterogeneous Heck reactions.