Application of palladacycles in heck reactions

Palladium-catalyzed cross-coupling reactions have been widely applied to the chemical industry, synthesis of natural products and biological active substances. The catalytic system is the key of cross-coupling reaction. Palladacycles, which have simple structures, stable properties and show high activity and selectivity as catalysts in the cross-coupling reactions, have attracted more attentions. Some new palladacycles are synthesized and their catalytic activities are studied in succession. In this paper, the synthesis methods and applications of palladacycles in the Heck reactions are reviewed.