Publication detail

Recyclable enantioselective catalysts for Henry reaction based on 2-(pyridine-2-yl)imidazolidin-4-thione derivatives

Authors: Drabina Pavel | Nováková Gabriela | Sedlák Miloš

Year: 2015

Type of publication: ostatní - přednáška nebo poster

Page from-to: nestránkováno

Titles:

Language	Name	Abstract	Keywords
eng	Recyclable enantioselective catalysts for Henry reaction based on 2-(pyridine-2-yl)imidazolidin-4-thione derivatives	Recently, we prepared very efficient and recyclable catalyst for Henry reaction based on Cu(II) complexes of (1R,2R)-2-(2,3-dihydro-1H-isoindole-2-yl)-1,2-diphenylethane-1,2-diamine anchored by swelling pearl-like copolymer styrene – 4-vinylbenzyl chloride cross-linked by tetra(ethylene glycol)-bis(4-vinylbenzyl)ether (2%). The aim of this work was preparation and study of enantiocatalytic activity in Henry reaction of heterogeneous catalysts based on Cu(II) complexes of 2-(pyridine-2-yl)imidazolidin-4-thiones anchored by mentioned copolymer via sulfur – carbon bond. At first, we prepared 2-(pyridine-2-yl)imidazolidin-4-thione and corresponding 4-benzylsulfanyl-2-(pyridine-2-yl)imidazoline derivatives. We found out that their Cu(II)-complexes showed comparable enantioselectivity in Henry reaction (up to 97 % ee) as analogous imidazolidin-4-one derivatives. Then, we prepared immobilized catalysts by reaction of 2-(pyridine-2-yl)imidazolidin-4-thione derivatives with chloromethylated swelling copolymer and subsequent complex formation by action of copper(II) acetate. These heterogeneous catalysts were tested in Henry reaction. We found out, that the reactions proceeded in the polymeric matrix of swelling catalysts at a rate comparable with that of the reactions using Cu(II)-catalysts in homogeneous medium. After tenfold recycling of the catalyst, slight lowering of yields and no lowering of enantioselectivity took place.

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