Copper-catalyzed Ring-opening 1,3-aminobromination Of Arylcyclopropanes:Synthesis Of γ-bromoamine Derivatives

Cyclopropane has high ring tension,and it is easy to release the C–C bond cleavage and occur to ring-opening reaction,and take part in various chemical transformations.Thus,these compounds are very important synthetic intermediates in organic synthesis.The ring-opening1,3-difunctionalization of cyclopropane can simultaneously introduce two functional groups into the C1-and C3-positions of the carbocyclic ring,which represents a straightforward and efficient access to 1,3-difunctionalized compounds.Up to now,although cyclopropane ringopening 1,3-difunctionalization,such as dichlorination,dicarbonization,dibromination,halovulcanization,aminoarylation,aminooxidation,aminofluorination,aminoazidation and other reactions,have been successfully realized,but the development of new 1,3-difunctionalization reactions of cyclopropane ring-opening is still highly desirable.γ-Bromoamines are a class of important organic compounds,which are an essential structural unit of natural products and are useful synthetic inmediates,having a wide range of applications in materials science and pharmaceutical chemistry.Therefore,their synthetic methods have become one of the hot research topics in organic synthetic chemistry.At present,the known synthesis of γ-bromoamine mainly include the bromination reaction of nitrogencontaining compounds and the amination reaction of brominated compounds.These raw materials always require the substrates with a special structure which usually were prepared through multi-step synthesis.Therefore,it is of great significance to develop a new synthetic method for the synthesis of γ-bromoamines with simple and easily available substrates.Based on ring-opening 1,3-difunctionalization of cyclopropane,and combing with the limitations of synthetic methods of γ-bromoamines,this thesis employed cheap copper salt as catalyst,N-fluorobisbenzenesulfonimide(NFSI)as the nitrogen source,lithium bromide as the bromine source to develope ring-opening 1,3-aminobromination of arylcyclopropanes,efficiently synthesizing a series of γ-bromoamine derivatives with medium to high yields.This reaction features mild conditions and good tolerace of the functional groups,which provides a new approach for γ-bromoamines.