ИСТИНА

To date, the chiral copper(II) and nickel(II) complexes are very attractive class of enantioselective homogeneous catalysts. Herein we wish to report the synthesis and characterization of chiral Cu(II) and Ni(II) complexes based on Schiff base of (S)-2-aminomethylpyrrolidine and salicylaldehyde derivatives including both Lewis and Brønsted acid/basic functionalities (Figure). In addition, their application as enantioselective catalysts in the Henry reaction and in the kinetic resolution of epoxides with CO2 was detailed (Figure).2,3 It was demonstrated that the water molecules play a crucial role in the reactivity of the Cu(II) complex in the asymmetric Henry reaction with up to 82% ee. The mechanism of the reaction was kinetically studied. The bridging OAc-ion functioned as the basic group, deprotonating nitromethane molecules. It was shown that water presence may become a crucial feature of the catalysis by copper(II) complexes. In the kinetic resolution of epoxides, the Ni(II) complex with iodide-anion in the combination with co-catalyst could provide the desired carbonates with the selectivity factor up to 10.