Application Of Iron Complex With Bipyrrolidine-derived Ligands In Asymmetric Catalysis

This thesis mainly focused on the application of Fe(Ⅲ)-BPsalan complex in asymmetric catalysis.With growing emphasis on health,there is an increasing need for new drug synthesis.In synthesis,higher requirements are put forward on the methodology: green,high-efficiency,and low-toxicity.Asymmetric catalysis is a key area of chemical synthesis,and iron,as a green metal,has positive significance for its application in asymmetric catalysis.Fe-BPsalan complex is an excellent transition metal catalyst.Examples of its asymmetric catalysis reactions have been reported,but it is still necessary to explore more suitable reactions to expand its application in asymmetric catalysis.In the first part of the thesis,Fe-BPsalan complex was employed to catalyze the asymmetric chlorination and dearomatization of 2-hydroxy-1-naphthol derivatives.Using Fe-BPsalan complex as catalyst,DCDMH as chlorinating reagent,5 mol%catalyst loading,asymmetric and efficient chlorination of 2-hydroxy-1-naphthol containing various substituents derivative.Chlorine-containing chiral naphthone can be obtained with up to 99% yield and 98% ee value.The reaction operation is simple,gram-scale amplification effect is equivalent,and it can also be extended to the asymmetric bromination dearomatization reaction.The brominated product has a moderately high yield and enantioselectivity.The second part studied the asymmetric Mukaiyama-Michael addition reaction ofα,β-unsaturated 2-acylimidazole catalyzed by Fe-BPsalan complex.After optimization,it was determined that the 3-Br,5-Br substituted Fe-BPsalan complex was the optimal catalyst,MTBE was used as the solvent and HFIP was the additive.The scope of the substrates is broad,and various substituted α,β-unsaturated 2-acylimidazoles reacted with various acyclic substituted enol silyl ethers to afford addition products in excellent enantioselectivity and yield.Extending substrates to the reaction with siloxyfuran,not only the product with high enantioselectivity and high yield is obtained,but diastereoselectivity of the reaction is well controlled.It realizes high-efficiency catalysis of various types of asymmetric Mukaiyama-Michael addition reactions comprehensively.As the substrates are readily available and the operation is simple,this catalysis is of high practical application.