Study On The Formal[3+2]Cycloaddition Reaction Of Azaoxyallyl Cations And Aromatic Ethylenes

The structure of pyrrolidone widely exists in natural products and drug molecules.The preparation of pyrrolidone via 1,3-dipolar cycloaddition has attracted much attention due to its easy availability of raw materials,simple operation,green chemistry and without pollution.In this paper,we mainly carried out [3+2] cycloaddition reaction on the efficient synthesis of multi-substituted pyrrolidones.In Chapter one,the the research progress of pyrrolidone compounds is reviewed,and the synthetic methods of pyrrolidone core are mainly introduced.According to the way of rings formation,this section is divided into five parts to elaborate: 1.Intramolecular cyclization reaction;2.Intermolecular cycloaddition or annulation reaction;3.Ring enlargement of ?-lactam reaction;4.Redox reaction;5.Other unclassified reaction.The intermolecular [4+1] and [3+2] cycloaddition reactions are reviewed in detail.In the second chapter,we briefly introduce the development of aza-oxa-allyl cationic intermediates and the formal [3+n] cycloaddition reactions to construct complex nitrogen-containing heterocyclic compounds.Based on this design mentality,we report the synthesis of multi-substituted pyrrolidones via a direct [3+2] cycloaddition of azaoxyallyl cations intermediate generated in situ from ?-halo hydroxamates with aryl ethylenes More importanlyl,this method has the advantages of easy availability of commercial materials,simplicity of operation,mild conditions.and good results of high reaction yields and excellent regioselectivity and in high diastereoselectivity(dr > 20:1).