Univerzita PardubiceFakulta chemicko- technologická

Univerzita Pardubice

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Publikace detail

Catalytic systems based on 1H-imidazol-5-one derivatives

Autoři: Drabina Pavel | Panov Illia | Karel Sergej | Sedlák Miloš

Rok: 2012

Druh publikace: ostatní - přednáška nebo poster

Strana od-do: nestránkováno

Tituly:

Jazyk	Název	Abstrakt	Klíčová slova
eng	Catalytic systems based on 1H-imidazol-5-one derivatives	Nitrogen ligands and their transition metal complexes belong among compounds widely used as homogeneous catalysts in many chemical processes. The nitrogen ligand containing stereogenic centre can be used as enantioselective catalyst for an asymmetric reaction. Therefore, we have recently developed several series of chiral imidazolinone and imidazolidinone derivatives with the aim to study their catalytic activity in various processes including asymmetric reactions. For example, rhodium(III) and iron(III) complexes of 2,6-bis(imidazolinyl)pyridine derivatives were found to be excellent catalysts for deallylation of substituted allylmalonates or alkylative cyclisation of substituted 2-chloroalka-1,6-dienes. The copper(II) complexes of 2-(imidazolinyl)pyridines showed in the asymmetric Henry reaction modest enantioselectivity. Nevertheless, the copper(II) complexes of analogical 2-(imidazolidinyl)pyridine derivatives are dramatically higher enantioselective catalysts for Henry reaction (optical yields increase from 19% ee up to 96% ee)4 and, therefore, this type of nitrogen ligands was considered as very perspective. In our most recent investigation, we have dealt with the structure modification of 2-(imidazolidinyl)pyridine derivatives on stereogenic centres to study the influence of ligand design on enantiocatalytic activity in Henry reaction. We found that ligands with anti-arrangement are generally more efficient than appropriate syn-derivatives. Surprisingly, the ligands with quarternary stereogenic centres derived from α-methylated 2-aminoacids are more enantioselective than the ligands derived from coded 2-aminoacids. Moreover, these ligands are more resistant to oxidation and racemization. Presented results indicate that this group of imidazolidinones represents new promising branch of enantioselective catalysts.	1H-imidazol-5-one; catalysis