Research On The Synthesis Of Functionalized Oxazoles And Indoles Via Copper-mediated Cascade Reactions

Transition metal-mediated coupling reaction is an effective strategy for constructing carbon-carbon and carbon-heteroatom bonds.Copper promoters have aroused wide concern of chemists because of their advantages such as low cost and low toxicity.Recently,the one-pot approaches to the synthesis of various heterocyclic compounds has become one of the hot spots because of their convenient procedures,high efficiency and environmentally benign properties.This dissertation mainly focuses on the studies on the synthesis of functionalized oxazoles and indoles through the copper-mediated cascade reaction.It includes three chapters.In the first chapter,the development of copper-mediated cross-coupling reactions and one-pot coupling/cyclic processes are introduced respectively.In the second chapter,we describe a facile and efficient one-pot synthesis of 2-o-cyanoaryl oxazole derivatives mediated by CuCN.A variety of substituted 2-o-cyanoaryl oxazole/oxazolines could be assembled in moderate to excellent yields from o-bromoN-propargylbenzamides and CuCN through a cyclization/coupling process.Various substituents were well tolerated under these conditions.In this transformation,CuCN plays dual roles as a Lewis acid catalyst and a cyanide anion source.Next,we introduce the research on the synthesis of 2-o-bromophenyl oxazoles derivatives via intramolecular cyclization of N-propargylbenzamides.Finally,we introduce the research study on the derivation of the 2-o-bromophenyl oxazoles.In the third chapter,a novel and facile synthesis of 2-heterocyclicmethyl indoles via domino reaction of gem-dibromovinyl anilines and the nucleophiles has been established.Promoted by catalytic amount of CuI,this transformation smoothly undergoes an intermolecular C-N coupling/double intramolecular cyclization process.Till now,the Cu-catalyzed synthesis of the 2-heterocycle-substituted methyl indoles has not been reported.