Synthesis Of α,β- Alkynones And 2,3,5-trisubstituted Pyrroles Promoted By DBU

Heterocyclic compounds play a vital role in organic compounds.Among them,pyrrole and its derivatives are one of the most significant heterocyclics,which have been frequently found in the molecules of the biologically natural compounds,pharmaceuticals,agricultural chemicals and synthetic materials.Meanwhile,they have been also widely used to prepare the complex natural products and photoelectric materials.Up till now,the methods for the synthesis of pyrrole and its derivatives have been widely reported.However,quite a few usually suffer some disadvantages.Consequently,the development of a novel,effective and straightforward methods to access pyrrole and its derivatives from the simple and available material under mild reaction conditions are still highly desirable.The thesis is divided into three parts:Chapter one: Progress in the application and synthesis of pyrroles and its derivativesIn this chapter,the applications of pyrroles and its derivatives in the fields of pharmacy,pesticides,food and material science have been briefly summarized.Meanwhile,the methods for the synthesis of the polysubstituted pyrroles have been described and discussed.Chapter two: Study on the synthesis of α,β-alkynones prompted by magnesium powderIn this chapter,“One-pot” synthesis of α,β-alkynones from Weinreb amides and phenylacetylene promoted by magnesium powder in the presence of n-butyl bromide was investigated.It was found that alkynyl magnesium reagent generated in situ from phenyl acetylene and n-butyl bromide in the presence of Mg powder could react with Weinreb amides to give the corresponding α,β-alkynones.The process has the advantages of easy operation and mild conditions,which offers a new method for the preparation of alkynone compounds.Chapter three: Study on DBU-mediated Synthesis of 2,3,5-Trisubstituted PyrrolesIn this chapter,a practical DBU-mediated Michael addition/cyclization of α,β-alkynones and α-amino acids is described,and a varity of 2,3,5-trisubstituted pyrroles were obtained in good yields.This protocol has the advantages of readily available starting materials,mild reaction conditions,and a wide scope of substrates,which provides a novel method for the synthesis of polysubstituted pyrroles.