Copper Nitrate-Participated Cyclization And Difunctionalization Reactions Of Alkenes And Alkynes

Copper nitrate trihydrate is a common inorganic copper salt,which features inexpensiveness,commercial availability,low toxicity,and easy handling.Considering of the tendency to atom economy and environmental friendliness for organic synthesis,the employment of inorganic salts as important organic reagents would provide more possibilities and synthetic routes in organic synthesis.Many efforts have been made on the construction of heterocyclic compounds and C-H functionalization in our group.Based on our previous results,this thesis will mainly focus on the reactions using copper nitrate as a crucial reagent and catalyst for the efficient construction of N-containing heterocycles and selective difunctionalization of alkynes or alkenes,respectively.1.Copper nitrate promoted synthesis of isoxazolinesA multicomponent[2+2+1]cyclization of copper nitrate,alkynes and alkenes has been successfully realized with copper nitrate as the catalyst and the reagent for the efficient construction of pharmacologically interesting isoxazolines.Copper nitrate is used for the activation of carbon-carbon triple bond and employed as the novel precursor of nitrile oxides.Furthermore,the method has also been applied to the synthesis of spiro compounds that could be found in marketed drugs.Based on the in-depth investigation of the mechanism,we speculated that the reaction might undergo the transformation of alkynes to nitrile oxides through the activation of copper nitrate.2.Copper nitrate promoted difunctionalization of alkynesA series of a-chloro-?-nitroolefins have been afforded selectively from alkynes in moderate to excellent yields,where copper nitrate was employed as the nitro source and low toxic stannous chloride acted as the chlorine source.This protocol provides a direct access to polysubstituted alkenes with operational simplicity,good functional group tolerance,and a wide substrate scope.Furthermore,the gram-scale reaction could be conducted smoothly as well as various synthetic applications including nucleophilic substitution and cross coupling reactions,which indicates the significance of these crucial building blocks.Finally,two plausible routes were proposed to explain the formation of products with two opposite stereoconvergence.3.Copper nitrate promoted difunctionalization of alkenesThe synthesis of ?-bromonitrates has been revealed from simple alkenes in the presence of copper nitrate as the nitrate source and N-bromosuccinimide(NBS)as the bromine source.This approach provides an efficient access to nitrates with commercially available alkenes and operational simplicity.Copper nitrate is reported as the source of nitrate for the first time and acts as the crucial catalyst to promote the reaction as well.Finally,the primary investigation and discussion have been made for the plausible mechanism which may consist of both radical and ionic pathway.