Study On The Copper-catalyzed One-pot Synthesis Of N-heterocycles Based On Addition/Cyclization Process

Many nitrogen-containing heterocyclic compounds are of important value in the fields of drug synthesis,biochemistry,theoretical research,materials science,etc.For this reason,the synthesis of nitrogen-containing heterocyclic compounds is becoming more and more popular and receiving more and more attention.Transition metal-promoted addition is often more economic,convenient and efficient in the synthesis of many useful heterocyclic compounds than conventional synthetic methods.Compared with expensive transition metal catalysts,copper catalysts possess many advantages such as low cost,low toxicity,environmental friendliness and easy post-treatment.Therefore,copper catalsis has a very broad application prospect.In recent years,the one-pot transformation has attracted great attention because of its outstanding advantages such as high efficiency,convenience and green nature.Therefore,in combination with the above two organic synthesis strategies,copper-mediated tandem reactions for the construction of heterocycles has emerged as a new research area.It is more economic and practical to synthesize heterocyclic compounds through copper-catalyzed one-pot reactions.The research content of this paper is to synthesize nitrogen-containing heterocyclic compounds in a one-pot reaction around the addition/cyclization process.The main content includes three parts:The first part briefly outlines the development history of copper-catalyzed tandem reaction and the related research progress and application of intramolecular construction of N-heterocycle.The second part mainly introduces the one-pot synthesis of 4-iminotetrahydropyrimidin-2-one derivatives via copper-catalyzed tandem addition/CuAAC/ketenimine rearrangement/cyclization reactions of propargylamines,isocyanates and sulfonyl azides.In this research,we discovered a novel method for the synthesis of 4-iminotetrahydropyrimidin-2-one derivatives,which generates the heterocyclic products through copper-catalyzed multicomponent tandem addition/cyclization reactions in one pot.The third part mainly explores the synthesis of benzimidazo[2,1-b]thiazoles through a one-pot reactions of aryl isothiocyanates and propargylamines.In this transformation,trace amount of Cu catalyst was used for the addition/cyclization process and hypervalent iodine reagent was employed for the next intramolecular oxidative C-N coupling process.Compared with other methods,the substrates are easily accessible;the procedures are relatively simple,and the reaction conditions are milder.This method can be used for the efficient and convenient synthesis of various benzo[4,5]imidazo[2,1-b]thiazole compounds.