Applications Of Phase Transfer Catalysts Derived From Tertleucine And Quinine In Asymmetric Mannich Reactions

Asymmetric Mannich reaction is one of the effective methods to synthesize chiral amino compounds by forming new carbon-carbon bonds,which has attracted much attention in recent years.At present,asymmetric organocatalysis has become a hot topic in the field of asymmetric catalysis due to its advantages of environmental protection and low cost.In this thesis,the asymmetric organic catalytic Mannich reaction was investigated to construct chiral compounds with potential biological and pharmaceutical activities.To this end,the following work has been completed:1.A series of bifunctional phase transfer catalysts derived from L-tert-leucine were synthesized and applied to the intramolecular asymmetric Mannich reaction.Through the optimization of reaction conditions,the optimal reaction conditions were determined as follows:reaction temperature:-25?,catalyst loading of 10 mol%,m-xylene as solvent and potassium hydroxide as base.Under the optimal conditions,a series of optically pure 4-azaindoline optical isomers can be obtained respectively under the catalysis of urea quaternary ammonium derived from L/D-tert leucine.When L-configuration catalyst was used,the highest yield,ee and dr were 99%,90%and 99:1,respectively;When D-configuration catalyst was used,the highest yield,ee value and dr value of the product were 99%,91%and 99:1,respectively.The derivatization experiment of the corresponding products proves the practicability of the reaction.2.A series of bifunctional phase transfer catalysts derived from quinine were synthesized and applied for the first time in the asymmetric Mannich reaction of isatin derived ketimines with?-fluoroindanones.The results showed that the corresponding products were obtained in high yield(up to 99%),medium to good enantioselectivity(up to 76%ee)and excellent enantioselectivity(up to 99:1 dr)under the catalysis of catalyst7g and Cs₂CO₃ as base at-20?.