Synthesis And Application In Asymmetric Catalysis Of The New Chiral P/N-Ligands

Chiral C-C and C-N bonds are foundamental chemical bonds for the formation of many natural products and bioactive molecules. Therefore, the development of the methods for the construction of these chemical bonds is one of the most important topics in organic chemistry, especially using the asymmetric catalytic method. The asymmetric catalytic is a process that catalytic induce the prochirality compound into target product high efficiently and selectivity. We can’t implement this process without ligands. In this thesis, we have developed a series of new chiral P/N ligands and investigated their application in the Ag-catalyzed asymmetric [3+2] cycloaddition and Pd-catalyzed asymmetric allylic alkylations.1. This dissertation have designed and synthesized a series of new chiral bidentate P/N ligands with N-benzoxazole ring. We have explored an effective means of synthesis this type chiral P/N ligands.2-chlorinated benzoxazole and corresponding amines in DMF and iPr2Et conditions, we can obtain the corresponding ligands with high conversion. In addition, we successfully realized the function group with the combination of ferrocene skeleton.2. The catalyst generated in suit from AgOAc and the new chiral P/N ligands have proved to be highly effective in the asymmetric1,3-dipolar cycloaddition of azomethine ylieds with N-Phenylmaleimide. The reaction displayed sole endo-selectivity and high enantioselectivity up to99%e.e. In addition, this catalysts showed good tolerability to the azomethine ylieds.3. The catalyst generated in suit from [Pd(η3-C3H5)Cl]2and the new chiral P/N ligands have been successfully employed in the asymmetric allylic alkylations with1,3-diphenylallyl acetate and dimethyl malonate. The reaction displayed high enantioselectivity up to93%e.e. in the asymmetric allylic alkylations which successful induct chiral C-C bond-forming. The catalyst have proved to be highly enantioselectivity in the asymmetric allylic amination of1,3-diphenylallyl acetate with multiple primary amine up to78%-90%. At last, we investigated the application of new ligands in asymmetric allylic alkylations of1,3-diphenylallyl acetate with1-cyclohexenylpyrrolidine. It has showed good selectivity, but regional selective performance is very poor. In a word, we have found that this kind of new chiral P/N ligands is a kind of efficient catalytic asymmetric C-C bond, C-N bond-forming ligands.