Study On Catalytic Performance Of Chiral Thiourea Derivatives

In the past two decades,small organic molecule catalysis has been an important direction of asymmetric reaction research.Compared with most metal catalysts,small organic molecule catalysis has the characteristics of mild reaction conditions,high catalytic efficiency and little pollution to environment.Among these small organic molecule catalysis,the chiral thiourea catalyst can activate the reaction substrate by forming hydrogen bonds with the reaction substrate to promote the progress of the reaction.As the chiral thiourea catalyst has good catalytic activity,prominent enantioselectivity,mild conditions and other characteristics,it has attracted the attention of many scholars.The main contents of this paper are as followsFirst of all,a series of chiral thiourea derivatives were synthesized.Using chiral cyclohexanediamine and chiral amino acid as the starting material,the thiourea-tertiary amine catalyst,thiourea-primary amine catalyst,bis-thiourea catalyst,thiourea-amide catalyst and thiourea-amide catalyst were synthesized by a few steps of organic reaction.And the compounds were characterized by 1H NMR,13 C NMR and MS.Secondly,the thiourea-amide catalyst was screened for the study of epoxy ring-opening.Using the anline as nucleophilic reagent and the epoxycyclohexane as template,the optimum temperature,catalyst and solvent were confirmed by a series of single factor tests.And under the optimum reaction conditions,a dozen compounds were synthesized and the reaction products were characterized by 1H NMR and MS.Thirdly,further research on the use of the chiral catalyst for partial asymmetric organic reactions was done.The asymmetric Michael addition reaction,the asymmetric Knoevenagel condensation reaction,the asymmetric epoxy compound ring opening reaction as well as the asymmetric Biginelli were catalyzed respectively.The experimental results showed that the chiral catalyst had an outstanding catalytic effect on the epoxy ring-opening.On this basis the conditions were screened,which eventually improved the ee value to over 90%,and the yield is excellent.The reaction products were characterized by 1H NMR,MS and chiral HPLC.