Polymerization Amplified Stereoselectivity(PASS) Of Asymmetric Michael Addition Reaction And Aldol Reaction Catalyzed By Helical Poly(phenyl Isocyanide) Bearing Secondary Amine Pendants

Inspired by nature,more and more scientists have been working on spiral polymers in recent years.Spiral polymers have great applications in chiral recognition,chiral amplification,chiral amplification,etc.Recently,it has been found that spiral polymers are also widely used in asymmetric catalysis.Asymmetric catalysis is a method of constructing chiral molecules,and building chiral centers that link different groups.The most important for the asymmetric catalytic reaction is the reaction efficiency and selectivity of the reaction,and whether the catalyst can be recovered.As chemical scientists are increasingly advocating green chemistry,economical chemistry,and increasing the maximum utilization of atoms,in asymmetric catalysis,catalyst recovery and recycling has become a hot spot for asymmetric catalysis.It is well known that small molecule catalysts catalyze asymmetric reactions,have slow reaction rates,complex reaction products,are not easily separated from the product,small molecule catalysts for reaction are not easily removed,and small molecule catalysts are not easy to recover.In recent years,the advantages of macromolecular catalysts have become more and more prominent,especially the advantages of spiral polymers in asymmetric catalysis are becoming more and more obvious.The macromolecular catalyst catalyzes the asymmetric reaction,the reaction is thorough,the reaction product is clean,the reaction product is easy to separate,and the macromolecular catalyst is easy to recover.The helical polymer not only has the advantages of the above macromolecular catalyst in asymmetric catalysis,but also has the advantage of improving the stereoselectivity of the asymmetric catalytic product.The solvent for the asymmetric reaction of the proline-modified spiral polyisonitrile is water,green and environmentally friendly,in line with the concept of green chemistry.In this paper,the proline-modified isonitrile monomer was prepared and polymerized to prepare a macromolecular catalyst to catalyze the asymmetric Michael addition reaction and Aldol reaction.The catalyst recovered in the asymmetric Micheal addition reaction can cyclically catalyze the asymmetric Micheal at least 5 times,and the stereoactivity of the reaction activity and reaction product is not much lost.The catalyst obtained by the recovery of the asymmetric Micheal addition reaction was used to catalyze the Aldol reaction,and was cyclically catalyzed 6 times between the Micheal addition reaction and the Aldol reaction.The obtained product ee value was not significantly reduced,that is,the helical macromolecule.The stereoselectivity of the product not significantly reduced.