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  • Synthesis, Characterization...
    Tovmasyan, Anna S; Mkrtchyan, Anna F; Khachatryan, Hamlet N; Hayrapetyan, Mary V; Hakobyan, Robert M; Poghosyan, Artavazd S; Tsaturyan, Avetis H; Minasyan, Ela V; Maleev, Victor I; Larionov, Vladimir A; Ayvazyan, Armen G; Shibata, Norio; Roviello, Giovanni N; Saghyan, Ashot S

    Molecules (Basel, Switzerland), 01/2023, Volume: 28, Issue: 3
    Journal Article

    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.