Formation of C-C and C-Heteroatom Bonds by C-H Activation by Metal Organic Frameworks as Catalysts or Supports

Cross-coupling reactions catalyzed by transition metals are currently among the most widely used transformations in organic synthesis. In most of these reactions, the coupling involves the reaction of two complementary functional groups, particularly boronates and halides. For the sake of atom economy and simplicity of the starting materials, it is more advantageous when the coupling involves C-H activation of one substrate lacking a reactive functional group. The present review focuses on the use of metal organic frameworks (MOFs) as solid reusable catalysts to promote cross-coupling reactions involving C-H activation. After general considerations, the review is organized according to the bond formed in the coupling, either C-C or C-heteroatom (N, O, B and X). The purpose of this mini review is to show the performance of MOFs as heterogeneous catalysts in these reactions, combining a high activity due to the large percentage of accessible metal sites and high stability allowing the reuse of the material in consecutive cycles. Comparison with homogeneous analogous catalysts indicates that this improved performance derives from the porosity, large surface area and site isolation and immobilization occurring in the MOFs. Considering the growing interests in these reactions the last section forecasts future developments in these areas in near future.