Ligand‐Free Copper‐Catalyzed Coupling of Phenols with Nitroarenes by using a Metal–Organic Framework as a Robust and Recoverable Catalyst

Abstract A highly porous metal–organic framework Cu 2 (BDC) 2 (DABCO) (H 2 BDC=1,4‐benzenedicarboxylic acid, DABCO=1,4‐diazabicyclo[2.2.2]octane) was synthesized and used as an efficient recyclable heterogeneous catalyst for the coupling reaction of phenols with nitroarenes to form diaryl ethers without using a ligand. Physical characterization of the MOF was obtained by using XRD, SEM, TEM, thermogravimetric analysis (TGA), FTIR spectroscopy, atomic absorption spectrophotometry (AAS), H 2 temperature‐programmed reduction (H 2 ‐TPR), and N 2 physisorption measurements. The Cu 2 (BDC) 2 (DABCO)‐catalyzed coupling reaction offers several advantages compared to the conventional Ullmann reaction for the synthesis of unsymmetrical diaryl ethers. To the best of our knowledge, the ligand‐free Cu‐catalyzed O‐arylation reaction of phenols with nitroarenes that uses a heterogeneous catalyst has not been mentioned previously in the literature.