Chiral Phase-transfer Catalyst Synthesis And Asymmetric Induction

Asymmetric synthesis using chiral phase transfer catalyst is a new method that has just been developed in recent years. The purpose of this paper is to synthesize some new chiral quaternary ammonium salts and bisquaternary ammonium salts from the popular cheap material-L-tyrosine. And then we used these chiral quaternary ammonium salts in some substitution reactions and addition reactions in order to study their catalytic function and asymmetric induction.The folio wings are the main work of my paper :1. It summarized the development and the recent research work on using chiral quaternary ammonium salts as phase transfer catalysts in recent years.2. Using L-tyrosine as the starting material, by the reaction of acetylation, etherification, deacetylation, esterification and neutralization, we get p-methoxy -L-phenylalanine methyl ester. Then we did the following syntheses with it.(1) Using p-methoxy-L-phenylalanine methyl ester as the starting material, by the reaction of quaterization we get PTC-1.(2) Using p-methoxy-L-phenylalanine methyl ester as the starting material, by the reaction of benzylation and quaterization we get PTC-2.(3) Using p-methoxy-L-phenylalanine methyl ester as the starting material, after reacted with 1, 6-dibromohexane at 2:1, it was quaterized by CH3I and became PTC-3.3. With the deoxidation of the p-methoxy-L-phenylalanine methyl ester, we get p-methoxy-L-phenylalanine alcohol. Then we did the following synthsis with it.(1) Using p-methoxy-L-phenylalanine alcohol as the starting material, by the reaction of quaterization we get PTC-4.(2) Using p-methoxy-L-phenylaianine alcohol as the starting material, by the reaction of benzylation and quaterization we get PTC-5.(3) Using p-methoxy-L-phenylalanine alcohol as the starting material, after reacted with 1, 6-dibromohexane at 2:1, it was quaterized by CH3 I and become PTC-3.4. All the chiral quaternary ammonium salts and the intermediates we have synthesized were characterized by 'H-NMR and MS.5. In order to study the catalysis function and asymmetric induction effect of these chiral quaternary ammonium salts, we used them as chiral phase transfer catalysts in the reaction of substitution and addition.6. A mode for the asymmetric induction of the chiral phase transfer catalysts was suggested on the basis of the results of the experiments and the relate theories.