Abstract Novel chiral polymers containing cinchona-based squaramides in their main chain structure were designed. We synthesized chiral squaramides bearing two cinchona moieties, which contain double bonds. Repeated Mizoroki-Heck reactions between… Click to show full abstract
Abstract Novel chiral polymers containing cinchona-based squaramides in their main chain structure were designed. We synthesized chiral squaramides bearing two cinchona moieties, which contain double bonds. Repeated Mizoroki-Heck reactions between the double bonds of the cinchona-based squaramide and aromatic diiodides proceeded smoothly to give cinchona squaramide chiral polymers. The catalytic activity of the chiral polymers was subsequently investigated. The asymmetric Michael addition of β-ketoesters to nitroolefins was successfully catalyzed by the polymeric organocatalysts to give the corresponding Michael adducts in good yields and excellent enantioselectivities of up to 99% ee . As the polymeric catalysts were insoluble in commonly used organic solvents, they were easily recovered from the reaction mixture and reused for further reaction without any loss of catalytic activity.
               
Click one of the above tabs to view related content.