Ricerc@Sapienza

Even though homogeneous phase asymmetric catalysis allows to obtain optical active products with high yields and enantiomeric excesses, it is generally associated with a difficult and expensive recovery of the catalyst from the reaction mixture. Therefore, in the last few decades it has grown the interest in heterogeneous phase catalysis using nanoparticles as solid supports, which can provide both advantages of homogeneous and heterogeneous phase catalysis, namely, simple recovery and high catalytic activity. In this work we present the magnetic recoverable nanostructured catalyst L1, made up of an ephedrine-derived ligand immobilized on azido functionalized silica-coated magnetite nanoparticles. At the beginning we synthetized two homogeneous phase ephedrine-derived ligands, L2 and L3, to verify their catalytic activity in the Henry reaction. In this communication we report the employment of the mentioned ligands in the enantioselective Henry reaction. We confirmed the high catalytic activity of ephedrine-type catalytic site testing ligands L2 and L3 in the addition of nitromethane to various aromatic aldehydes. Furthermore, preliminary heterogeneous phase tests on L1 have led to outstanding results, and its catalytic activity has been retained for three catalytic cycles. Further studies are currently underway