Study On Asymmetric Chlorination Catalyzed By Iron Salan Complexes With Chiral Bipyrrolidine Backbone

In recent years,the concept of green chemistry has been deeply rooted in the hearts of the people.Iron,a cheap,rich,environmentally friendly metal,has obvious advantages compared to the precious metals and has attracted wide attention.In addition,rigid chiral bipyrrolidine backbone BPsalan metal complexes are a kind of good chiral catalyst.They have the advantages of simple synthesis and stable property,which the general salen metal complexes have,and can also avoid the problem that the configurations are not stable.Therefore,we want to synthesize the Fe-Bpsalan complexes and apply them to asymmetric catalytic reactions.?-ketoesters and oxindoles compounds protected by N-Boc have potential medicinal value,and the chlorine atom can be introduced into their molecules by asymmetric chlorination in order to realize further conversion.We synthesize the green cheap Fe-BPsalan complexes and apply them to catalyze the asymmetric chlorination reaction of two kinds of 1,3-two carbonyl substrates.The products were able to obtain good yields and moderate to excellent ee values.The asymmetric chlorination reaction systems of ?-ketoesters and N-Boc oxindoles were enriched.In addition,the catalytic system can also be used in asymmetric bromination reaction in a preliminary attempt,combined with previous work,proving that the chiral bipyrrolidine backbone iron salan complexes are effective catalysts in asymmetric halogenation(fluorination,chlorination,bromination)reactions.