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

Abstract

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 CC 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.

Expanding the Variety of Zirconium‐based Inorganic Building Units for Metal–Organic Frameworks

“…Theq uality of the extracted reflection intensities can be increased by coupling ADT with precession electron diffraction (PED). [36][37][38][39][40] Arylboronic acids are very important intermediates in organic synthesis that can be used in ap lethora of synthetic procedures. [34,35] This is especially relevant in the rich domain of C À Ha ctivation catalysis,w ith formation of for example,C ÀC, CÀN, or CÀBb onds.…”

Aerobic Oxidation of Benzylic Hydrocarbons by Iron‐Based Metal Organic Framework as Solid Heterogeneous Catalyst

“…It is interesting to note that Fe(BTC) is able to provide higher selectivity under the present experimental conditions than the catalytic system using Fe(BTC) and TBHP as oxidant (71% selectivity). [47] Similarly, Fe(BTC) showed 12% conversion of acenaphthene with 77% of the combined selectivity of ol/ one under identical conditions (entry 5, Table 3). Also, isochromone was converted (16%) to its corresponding ketone with > 99% selectivity (entry 6, Table 3).…”

Iron‐Based Metal‐Organic Frameworks (MOF) as Photocatalysts for Radical and Cationic Polymerizations under Near UV and Visible LEDs (385–405 nm)

“…The investigated MOFs and other chemical compounds are shown in Table 1 and Scheme 2. MIL100 (either as microor nano-metric particles-MIL100nano), MIL127, MIL88A, MIL88B, and MIL53 materials, presented in detail in the references, [27,[35][36][37] were hydro/solvothermally synthesized, as previously reported. [28,30,31,[38][39][40] Diphenyliodonium hexafluorophosphate (Iod), N-vinylcarbazole (NVK), and the other reagents and solvents were purchased from Sigma-Aldrich or Alfa Aesar for the highest purity available and used as received without further purification.…”