Distinguishing between the homogeneous and heterogeneous mechanisms of catalysis in the Mizoroki-Heck and Suzuki-Miyaura reactions: Problems and prospects

This review presents a critical analysis of experimental methods used in distinguishing between the homogeneous and heterogeneous catalytic mechanisms in the Mizoroki-Heck and Suzuki-Miyaura reactions. The main problems arising in the interpretation of data obtained by these methods are discussed. It is demonstrated that it is necessary to take into account the dynamics of the interconversion of molecular, nanosized, and larger palladium species that is independent of the catalyst precursor type (dissolved or solid). The role of the in situ formation of colloidal palladium particles in the case of a supported catalyst precursor is considered.