Scientific and Production Center "Armbiotechnology" of NAS RA, 14 Gyurjyan Str., Yerevan 0056, Armenia.
Institute of Pharmacy, Yerevan State University, 1 Alex Manoogian Str., Yerevan 0025, Armenia.
Molecules. 2023 Jan 25;28(3):1180. doi: 10.3390/molecules28031180.
A new family of Cu(II) and Ni(II) salen complexes was synthesized and fully characterized through various physicochemical methods. Their catalytic activity was evaluated in the phase transfer C-alkylation reaction of the Schiff bases of D,L-alanine ester and benzaldehyde derivatives. It was found that the introduction of a chlorine atom into the - and -positions of the phenyl ring of the substrate resulted in an increase in both the chemical yield and the asymmetric induction ( 66-98%). The highest enantiomeric excess was achieved in the case of a Cu(II) salen complex based on (,)-cyclohexanediamine and salicylaldehyde at -20 °C. The occurrence of a bulky substituent in the ligand present in the complexes led to a drastic decrease in and chemical yield. For instance, the introduction of bulky substituents at positions 3 and 5 of the phenyl ring of the catalyst resulted in a complete loss of the stereoselectivity control in the alkylation reaction.
合成了一组新的 Cu(II) 和 Ni(II) 的 salen 配合物，并通过各种物理化学方法对其进行了充分的表征。通过相转移 C-烷基化反应，评估了它们对 D,L-丙氨酸酯和苯甲醛衍生物的席夫碱的催化活性。研究发现，在底物的苯环的 - 和 - 位引入氯原子，会导致化学产率和不对称诱导（66-98%）的提高。在 -20°C 的情况下，基于（,）-环己二胺和水杨醛的 Cu(II) salen 配合物的对映体过量最高。在配合物中配体上存在大体积取代基会导致和化学产率的急剧下降。例如，在催化剂的苯环的 3 位和 5 位上引入大体积取代基，会导致烷基化反应中立体选择性控制完全丧失。
