Study On Cyclization Reactions Using Aziridines As Dipoles

For a long time,aziridine structure plays an important role in the area of biology and chemistry,medicine,and receives widespread attention.The high strained three membered ring system makes aziridine be a significant building block in synthetic chemistry.Nucleophilic ring opening and cycloaddition reactions,substitution reaction are typical converting process of aziridines.This paper mainly focuses on the cycloaddition reaction of aziridines,and develops novel path of high order ring building.The research consists of the following two parts:Part one:[3+3]Cycloaddition of ?-Diazocarbonyl Compounds and N-Tosylaziridines to Synthesize 2H-1,4-Oxazines through Catalysis of Transition MetalUsing AgOTf and Cu(OAc)2 as catalysts,NaHCO3 as base for reaction of aziridines and a-Diazocarbonyl Compounds in 1,2-DCE at 40? for 12 h,Polysubstituted 2H-1,4-Oxazine generated in good yield.This transformation featured as mild reaction conditions and operational simplicity,versatile substrate scope.Part two:Transition-Metal Free Cyclization of Aziridines and.?,?-Unsaturated HydrazonesIn the mixture of toluene and DMF and Cs2CO3 used as base,reaction of aziridines and ?,?-unsaturated hydrazones at 60? for hours,and conducted hetero seven-membered rings in considerable yield.This transformation featured as transition-metal free,mild reaction conditions and operational simplicity.