Asymmetric Henry Reaction Catalyzed by Copper(II) Complexes of Substituted Imidazolidin-4-ones
Institute of Organic Chemistry and Technology, Faculty of Chemical Technology, University of Pardubice, Pardubice
Keywords: Henry reaction, enantioselective catalysis, copper complexes, recyclable catalysts
This review summarizes recently published results of research on the enantioselective catalysts based on copper(II) complexes of substituted 4,5-dihydro-1H-imidazol-5- -one and imidazolidine-4-one derivatives and their application in asymmetric Henry reaction. The enantioselectivity of 4,5-dihydro-1H-imidazol-5-one derivatives was generally low, nonetheless the transformation of the original 4,5-dihydro-1H-imidazol-5-one into the imidazolidine-4- -one ring led to a fundamental enhancement of enantioselectivity (19 % ee to 92 % ee). The most efficient homogeneous catalysts based on imidazolidine-4--one derivatives were anchored to three different supports: a block copolymer; a swelling pearl-like polymer and magnetic nanoparticles. The influence of the type of the immobilization on the chemical yields and the enantioselectivity of Henry reaction was compared and discussed. Immobilized catalysts were reused and their catalytic efficiency after several cycles of application was studied.
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