Asymmetric Cu-catalyzed Henry reaction using chiral camphor Schiff bases immobilized on a macromolecular chain

Abstract

Immobilized catalysts have attracted chemists’ attention for long time because of convenient recycling, which is very important for some special catalyst even immobilizations accompanying the decrease of catalytic activity and selectivity. Our group focused on the developing chiral catalysts with camphor framework to catalyze various asymmetric reactions for long time. For easily recycling the unique chiral catalysts, a series of polymer catalysts with chiral camphor unit were synthesized by RAFT polymerization. Herein, the performance of the synthesized polymer chiral catalysts was reported by catalyzing asymmetric Henry reaction. After optimizing the reaction conditions, the synthesized chiral polymer catalyst provides a good yield and enantioselectivity to the reaction of p-nitrobenzaldehyde and nitromethane. In the meantime, the recycles and reused properties of synthesized polymer catalysts were examination by the model asymmetric Henry reaction. The catalyzed activities and enantioselectivities did not show obviously decrease until recycling five times.