Study On The Synthesis Of Indolofurans By Copper-catalyzed Nitrene Transfer Reaction

Transition metal-catalyzed dearomatization reaction is one of the forefront research fields of chemical scientists in recent years.The dearomatization reaction can convert a large amount of planar aromatic compounds into various high-value-added products,and transition metal catalysis can be used to build various chemical bonds for different reaction sites of chemical molecules,which is also an important research direction.This includes the direct construction of C-N and C-O bonds under the catalysis of transition metals.Therefore,it is of great practical and theoretical significance to make full use of the specificity of transition metal-catalyzed dearomatization reactions to assemble complex polycyclic structures from easily available aromatic raw materials.The research content of this paper is to study the dearomatization amination reaction of tryptol or tryptamine with aryl azide with the participation of Cu andβ-diketonimine ligands.Under simple and mild reaction conditions,using cheap metal copper salt（CuBH₄（PPh₃）₂）as a catalyst,this method effectively constructs two chiral centers,and obtains a series of indolofurans in good yield.The experimental study of the mechanism shows that the reaction produces copper-nitrogen compounds and initiates the reaction.Then,copper-amino radicals are generated by intramolecular hydrogen transfer.Finally,the nucleophilic reaction of tryptanol or tryptamine hydroxyl or amino group is achieved through free radical coupling.The desired product is formed.