Chiral Cu(salen)-Based Metal–Organic Framework Including Mixed Ligands for the Selective Oxidation of Primary Alcohols and the Asymmetric Henry Reaction

The development of efficient chiral metal–organic framework (CMOF) catalysts with open active metal sites is crucial in asymmetric organic synthesis. In this work, Zn salt, a chiral metallosalen N-donor linker (CuL), and [1,1′-biphenyl]-4,4′-dicarboxylic acid (H2BPDC) were used in a solvothermal process to create a three-dimensional (3D) chiral Cu(salen)-based MOF, {[Zn2(CuL)(BPDC)2]·2DMF·H2O}n (1). Compound 1 reveals a 2-fold interpenetrating 3D net with high permanent porosity (752 m2/g, BET) using powder and single-crystal X-ray diffraction, IR spectroscopy, thermogravimetry, circular dichroism (CD) spectroscopy, and elemental analysis techniques. Framework 1′ (desolvated) in combination with TEMPO has remarkable catalytic activity for the selective oxidation of primary alcohols to benzaldehydes (yield up to 98%) in air at ambient temperatures. In addition, 1′ can be utilized as an effective heterogeneous catalyst for the asymmetric Henry reaction, with broad substrate application and good enantioselectivity (ee up to 91%). This study expands the family of functional MOFs based on chiral metallosalen ligands and demonstrates their potential for catalysis.