N-Heterocyclic Carbene Catalyzed Asymmetric Annulation For The Construction Of Pyrrolones And Spirocyclicooxindoles

As a new catalytic model,organic small molecule catalysis has made remarkable achievements in recent years.In particular,the asymmetric catalytic reactions involving N-heterocyclic carbene(NHC)provide reliable research ideas and synthesis methods for the construction of the core framework of various natural products and drug molecules.This thesis is mainly divided into the following three chapters:The first chapter describes the reaction involving unsaturated acylazole and homoenolate intermediates.Under the action of NHC,α,β-unsaturated acyl positive ions can be generated by,α,β-unsaturated alkynoaldehydes,α,β-unsaturated enaldehydes,ester compounds andα-bromoenaldehydes,which participate in the cyclization reaction as electrophiles Moreover,NHC can also interact with α,β-unsaturated carbonyl compounds(to polarity reversal their β site)to generate homoenolate intermediates as nucleophiles to participate in the construction of compounds.In the second chapter,using NHC as chiral catalyst,the highly efficient asymmetric construction of dihydropyranone pyrrole derivatives was completed through the[3+3]cycloaddition reaction between enaldehyde and pyrrole-4-one catalyzed by NHC.Based on previous research the[3+3]cycloaddition reaction between alkynyl aldehyde and pyrrole-4-one was developed and the synthesis of pyrrole-pyrrole-derivatives was realized,further exploration on the asymmetric synthesis of biaryl base chiral compounds was made,which certain experimental data obtained.At the same time,we also carried out the construction of indole derivatives with α,β-γ,δ-unsaturated aldehyde and pyrrole-4-one as starting materials.This reaction strategy is simple,efficient and environmentally friendly,and meets the requirements of green chemistry.It provides a reliable method to efficiently synthesize asymmetric construction of dihydropyranone pyrrole derivatives and pyranone pyrrole derivatives.In the third chapter,the asymmetric construction of spirocyclinolones was completed by the[3+2]cyclization reaction between α,β-unsaturated aldehydes and iso-indigo catalyzed by NHC.Through one-step reaction,this strategy can achieve the asymmetric construction of three continuous chiral centers,two of which are adjacent quaternary carbon chiral centers The strategy has overcame the problem of the construction of adjacent quaternary carbon chiral centers,thus provided a reliable method for the synthesis of optically pure indoloneone spironoid compounds.