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- Title
Synthesis of Cinchona Urea Polymers and Their Evaluation as Catalyst in the Asymmetric Reactions
- Authors
Abdelkawy, Mahmoud A.; Aly, El‐Saied A.; El‐Badawi, Mahmoud A.; Itsuno, Shinichi
- Abstract
Chiral polyureas of cinchona alkaloids were synthesized via repetitive Mizoroki‐Heck (MH) coupling reaction. The Pd‐catalyzed polycondensation of cinchona urea dimers 6 and aromatic diiodide 7 afforded the chiral polyureas (P1−P4). The catalytic activity of the chiral polymers was subsequently investigated. The asymmetric Michael addition of ketoesters to nitroolefins was successfully catalyzed by the polymeric organocatalysts (P1−P4) to give the corresponding Michael adducts with high catalytic activities and excellent enantionselectivities (up to >99% ee). The polymeric catalysts were insoluble in commonly used organic solvents. They were easily recovered and reused several times without any loss of the catalytic activity.
- Publication
ChemistrySelect, 2020, Vol 5, Issue 21, p6294
- ISSN
2365-6549
- DOI
10.1002/slct.202001436