High Selectivity Construction Of Thiophene Derivatives Based On Thioamide

Thiophene derivatives are very important intermediates or raw materials in pharmaceutical synthesis and industrial production in today's society.Thiophene derivatives play a decisive role in the field of drug synthesis,and also attract medical and chemical researchers' attention for their significant biological activity.The main contents of this article are two methods for the highly selective synthesis of polyfunctionalized thiophene derivatives based on thioamides:(1)Efficient synthesis of thiophene derivatives based on cascade reaction of thioamides;(2)Selective synthesis of thiophene,dihydrothiophene derivatives based on the control of substrate and condition.Both of these methods construct thiophene derivatives via cascade reaction,and supply a green and efficient avenue to the synthesis of polyfunctionalized thiophene.We will divide the paper into three chapters to intrduce research progress of thiophene derivatives.The first chapter is a brief overview of the research on thiophene derivatives,reviewing the main applications of thiophene derivatives in various fields in recent years,the main ways to synthesize polyfunctionalized thiophene,as well as the synthesis of polysubstituted thiophene derivatives via cascade reaction and the purpose,significance of the research.The second chapter demonstrates a synthetic method of high diastereoselective dihydrothieno[2,3-c]chromene derivatives via domino Michael addition catalyzed by Lewis base from 3-nitro-2H-chromene and thioamides.The method utilizes the strong nucleophilicity of thioamides to achieve Michael addition with 3-nitro-2H-chromene,and the generated intermediate is then cyclized intramolecularly by its own umpolung.Thereby we build polyfunctionalized dihydrothieno[2,3-c]chromene successfully.Dihydrothiophene derivatives are easily converted to thiophene derivatives,and the compounds can be obtained by using the one-pot method under the optimized conditions.This method has advantages of simple operation,convenient post-processing,meanwhile,is friendly to environment and efficient.The third chapter introduces the selective synthesis of thiophene,dihydrothiophene derivatives via controlling substrate and condition.The synthesis of trans-dihydrothieno[3,4-c]chromene derivatives by one-pot reaction with sulfonium bromide and N-phenyl-3-thiocarboxamide coumarin;the construction of cis-dihydrothieno[3,4-c]chromene derivatives by cascade reaction with bromine compounds and N-phenyl-3-thiocarboxamide coumarin;and using bromine compounds and N-phenyl-3-thiocarboxamide coumarin to synthesize thieno[3,4-c]chromene derivatives via one-pot reaction.This method can selectively synthesize a pair of diastereoisomers of polyfunctionalized dihydrothieno[3,4-c]chromene under the simple modification of the substrate,and obtain the single product with high yield after the condition is optimized,it can also efficiently obtain thieno[3,4-c]chromene compounds by one pot reaction,providing reseachers with a novel,green and efficient method to synthesize a variety of polyfunctionalized thiophene derivatives.