| The asymmetric construction reactions of C-C,C-N bonds share important status in organic synthesis methodology,which are widely involved in many fields as pharmaceuticals,materials,life and power source.Among these reactions,asymmetric C-C,C-N bonds construction reactions of aromatic ring frameworks in aromatic compounds are mostly electrophilic aromatic substitution(S_EAr),while construction reactions of asymmetric C-C,C-N bonds of aromatic ring frameworks through nucleophilic aromatic substitution(S_NAr)are rarely studied.Researches of S_NAr reactions can help enlarge the reaction scope of substrates to the asymmetric construction of C-C,C-N bonds,and these are of great significance for scientific research and practical application.In this thesis,density functional theory M06-2X method was used to explore the reaction mechanisms of chiral phosphoric acid catalyzed nucleophilic substitution between azo naphthalenes and indole derivatives,carbazole derivatives respectively.Using the theoretical analysis methods as the quantum theory of atoms in molecules(QTAIM),non-covalent interaction(NCI)and so on to prove the mechanisms.Based on the calculated structural models,finally the simple rules were proposed to guide the choosing of proper catalysts or substrates for the experiments.There are mainly four chapters in this thesis:Chapter 1:Introduction.This chapter briefly introduced the research background and advances of nucleophilic aromatic substitution reactions,catalysis and activation effects of hydrogen bond,and the research problems and significance of this thesis.Chapter 2:Theoretical basis and analytical methods.This chapter briefly introduced density functional theory(DFT),transition state theory(TST),solvation effect model theory and primary theoretical analytical methods:reaction indexes prediction based on the framework of conceptual density functional theory(CDFT),Fukui function,quantum theory of atoms in molecules(QTAIM),non-covalent interaction(NCI),distortion/interaction energy analysis and so on.Chapter 3:Theoretical investigation of chiral phosphoric acid catalyzed nucleophilic substitution reaction between azo naphthalenes and indole derivatives.In this chapter,the reaction mechanism of nucleophilic aromatic substitution reaction between azo naphthalenes and indole derivatives catalyzed by chiral phosphoric acid was introduced in detail.We used the Minnesota hybrid functional M06-2X,and basis set 6-31G(d,p)to execute the geometry optimization under the IEFPCM solvation model,furthermore,the single point energy calculations of according geometries were carried out using the basis set Def2-TZVP.The calculation results showed that this reaction was firstly initiated via dual hydrogen bond activation mode,and the results of QTAIM analysis also indicated this.The chirality of the bonding substrates was determined once the nucleophilic aromatic attack reaction occurs in the early stage of this reaction.From the structures of transition states of the nucleophilic aromatic attack corresponding to different reaction modes,the skeleton and Ar group of catalysts provided chiral environment,which dominantly determined the enantioselective catalysis and activation for substrates.In addition,we could see that other types of weak interactions exist between the catalyst and substrates from the QTAIM analysis,and this contributed to the stabilization of transition states.According to the results by NCI analysis,other types of intermolecular weak interactions possessed definite spatial distribution between catalyst and substrates,substrate and substrate.Chapter 4:Theoretical investigation of chiral phosphoric acid catalyzed nucleophilic substitution reaction between azo naphthalenes and carbazole derivatives.In this chapter,the reaction mechanism of nucleophilic aromatic substitution reaction between azo naphthalenes and carbazole derivatives catalyzed by chiral phosphoric acid was introduced in detail.We adopted density functional method M06-2X and basis set 6-31G(d,p)to carry out the geometry optimization under the SMD solvation model,and the basis set Def2-TZVP was applied to finish the single point energy calculations for the corresponding structures.Catalyzed by chiral phosphoric acid,azo naphthalenes and carbazole derivatives were successively activated,which was also realized by dual hydrogen bond activation mode.Based on the difference of the bonding modes between substrates and catalyst,causing the disparity of spatial arrangement,this reaction realized the regulation of enantioselectivity through the steric repulsion interaction between substrates and skeleton,Ar group of catalysts.By analyzing the structures of a pair of transition states that determined the stereoselectivity,we proposed the rule that enantioselective behavior of this reaction is influenced by the extent of how much the chiral pocket of phosphoric acid matches the size of substrates.The following theoretical calculations and literature investigation also indicated that it is reasonable to analyze and estimate the enantioselective behavior of chiral phosphoric acid catalyzed systems based on the pair of transition states which are stereoselective-determined steps,and the rule that the extent of how much the size of chiral pocket of phosphoric acid matches the size of substrates can be used to predict the enantioselective behavior of these reactions in a certain range of systems... |
PDF Full Text Request