Structural and mechanistic studies of Pd-catalyzed CC bond formation: The case of carbonylation and Heck reaction

The extraordinary catalytic activity of palladium in CC bond forming processes is reviewed in respect to Heck and carbonylation reactions. Examples of catalytic systems based on palladium complexes with phosphorus ligands and phosphine-free systems and based on the Pd(0) colloid are presented. The two key steps of both reaction mechanisms: first, reduction of Pd(II) to Pd(0) complexes or Pd(0) colloids and second, oxidative addition of substrates (aryl or benzyl halides) are discussed.