Studies On The Synthesis Of Substituted Furans Compounds And Thiophenes Compounds

Polysubstituted furans and thiophenes have great application value and development potential in the fields of bio-pharmaceutical,material science,and are important structural elements in natural products and pharmacologically molecules.In addition,they are important intermediates in organic synthetic chemistry.Therefore,the development of new approaches to synthesize polysubstituted furans and thiophenes under mild conditions with high selectivities is highly desirable.This dissertation mainly involves the researches of synthesizing a series of polysubstituted furans and thiophenes.The results are as follows:Part I:In this paper,we have developed a radical reaction involved Fe?III?-catalyzed nitration of homopropargylic alcohols.This novel protocol formed polysubstituted nitrofurans via employing Al?NO₃?₃·9H₂O as the nitration reagent.In the mechanism research process,we have found that Al?NO₃?₃·9H₂O can generate nitro radicals due to its'high activity.Under the promotion of the nitro radicals,the homopropargylic alcohol's?-?bond is efficiently activated,along with a radical addition reaction.Moreover,polysubstituted nitrofurans were formed by tandem cyclization reactions.This reaction has the advantages of mild reaction conditions and simple operation.Part II:As one of the most important carbon-heteroatom bonds in organic chemistry,C-S bonds are frequently found in many important pharmaceuticals,active natural compounds,and functional materials.This paper has reported a novel route to synthesize thiophene aldehydes in one step through C–C bond cleavage and C–S bond construction useing cyclopropyl ethanol derivative as substrates.And the method uses cheap,low toxic and active potassium sulfide as sulfur source.Furthermore,DMSO plays a dual role of solvent and oxidant.This method is simple,efficient and tolerates a wide variety of functional groups.