Design,Synthesis And Application Of New Axial-chiral N-heterocyclic Carbenes

Heterocyclic carbenes (NHC) have excellent performance in the catalytic effect due totheir strong coordinating capability and easy modified structure. Recently, chiral NHCs havebecome the focus of the research in the field of chiral compounds. In this thesis, we designeda modular approach to axial chiral NHC containing binaphthyl by Pd-catalyzedcross-coupling reactions. The thesis is consisted with five chapters:The first chapter briefly introduces the structures, properties and synthesis of the NHC.Furthermore, we also briefly explain the purpose and significance of this project.The second chapter briefly described the conception, design of the new axial chiralaza-carbene.We designed a new type of axial chiral aza-carbene with C₂symmetry by usingthe aza-carbene as the core and the binaphthyl chiral axial as the chiral center, then designedthe synthesis method of this new aza-carbene.The third chapter elaborates the synthesis of new axial chiral imidazolium in detail. Byusing the developed of this simple method, we construct a chiral catalytic storage ofHeterocyclic carbenes.The fourth chapter presents the application of the novel chiral two-hydrogen imidazolesalt, amending the catalysts synthesized in the third chapter according to the effect reflected inapplication. Meanwhile, we designed our second generation of the chiral benzimidazoliumsalt.The fifth chapter elaborated the synthesis of this new axial of chiral benzimidazoliumsalt. We have synthesized a series of C₂symmetry axial chiral benzimidazolium salt, non-C₂symmetry axial chiral benzimidazolium salt and four-gear axial chiral benzimidazolium salt.Our laboratory is exploring the applications of the new axial chiralimidazolium salt, and wehope this new axially chiral imidazole salt will has an excellent catalytic asymmetric effect.Finally, a conclusion about this study is given. In addition, a list of compounds andcompound spectra are attached in this paper.