Achiral organoiodine-functionalized helical polyisocyanides for multiple asymmetric dearomative oxidations

Immobilizing organocatalyst onto helical polymers not only facilitates the catalyst recycling from homogeneous reactions, but also boosts enantioselectivity. In this work, achiral organoiodine-functionalized single left- and right-handed helical polyisocyanides were prepared from the same monomers, which catalyzed three asymmetric oxidations gave the desired products in high yields and excellent enantioselectivity. The enantiomeric excess of the target products was up to 95%. Remarkably, the enantioselectivity can be switched by reversing the helicity of the polymer backbone. The polymer catalysts can be facilely recovered and recycled in different asymmetric oxidations with maintained excellent activity and enantioselectivity.

Chiral catalysts immobilized on achiral polymers: effect of the polymer support on the performance of the catalyst

Achiral polymeric supports can have important positive effects on the activity, stability and selectivity of supported chiral catalysts.