Design And Application Of Chiral Metal Catalysts Based On Surfactants

As the only medium of chemical transformation in natural biological system,"water" has recently become a hot topic in green chemistry research.However,most of the traditional organic synthesis is carried out in organic solvents,including dissolving components and promoting chemical reactions.Compared with reactants,the large use of organic solvents has become a barrier to sustainable development.Using water as the reaction medium can not only reduce the impact of organic synthesis on the environment,but also help simplify the chemical process,create mild reaction conditions,sometimes produce unpredictable reactivity and selectivity.Therefore,water as a reaction medium has become an important topic in the field of chiral catalysis.However,when water is used as solvent,the incompatibility between water and organic matter is a common problem.Generally,the organic catalysis with emulsion as the medium is considered to be one of the effective ways to overcome the compatibility of water and organic matter and improve the concentration of reactants,thus greatly improving the reaction rate.Based on this background,we have developed a amphiphilic chiral catalyst,which can produce emulsion catalytic system in water medium and solve many difficulties in water phase asymmetric reaction.It provides a very good reference for the development of surfactant type catalytic system of asymmetric metal catalysis in water phase.This paper is divided into three parts:the first part summarizes the development and application of surfactant in the field of asymmetric catalysis in water;the second part is mainly to develop and study new surfactant type asymmetric metal catalysis system in water;the third part is the experimental part.In this paper,we have developed a series of Schiff base ligands with two tertiary amine functional groups and long-chain alkyl groups.In the presence of water,the ligand and metal coordinate in situ to form a surfactant type chiral catalyst.Such catalysts are not only the control center of stereoselectivity,but also have the properties of amphiphilic molecules.With the addition of a small amount of hydrophobic solvents,emulsion can be formed without any surfactant additives,forming a metal micelle medium with hundreds of nanometers in the aqueous environment,and locally increasing the reaction concentration and reaction rate of the substrate.We observed the existence of such micelles by TEM and SEM,and confirmed the existence of hydrophilic part by NMR and IR.