Suzuki reaction: mechanistic multiplicity versus exclusive homogeneous or exclusive heterogeneous catalysis

Comparative studies of the kinetics and selectivity of the Suzuki and Heck reactions, the modified tests on homogeneity-heterogeneity and an implementation of the solid-phase variant of the Suzuki reaction indicate a substantial contribution of the heterogeneous mechanism to the Suzuki reaction catalysis which is in contrast to the Heck reaction. The contributions of molecular complexes, colloidal Pd and the larger-sized particles to Suzuki catalysis depend on the nature of the catalyst precursor, the solvent and the temperature of the reaction. It has been established that these contributions change significantly during the reaction as well.