Preparation Of A Chiral Metal Ruthenium Catalyst And Study Of Tandem Reactions

As we all know the homogeneous catalyst has the advantages of high reactivity,mild condition and so on,but it is difficult to be recycled after the reaction,and the heterogeneous catalyst is good to solve this problem.After the reaction,the catalyst can be separation by a simple method from the reaction system to achieve the catalyst recycling.In many carriers of heterogeneous catalysts,mesoporous silica materials have attracted much attention in academia because of their specific pore structure,low density,large specific surface area,adsorption,sieving molecular ability and optical properties.In view of the advantages of this material,the research work of this paper is divided into two parts:(1): In this subject,We use tetraethoxysilane,1,2-bis(triethoxysilane)ethane and(S,S)-4-(trimethoxymethylsilane)ethylphenylsulfonyl-1,2-diphenyldiamine in an alkaline aqueous solution copolymerized,then etched in an alkaline solution into a functionalized mesoporous hollow nanomaterials with ethyl silane as a backbone,then coordinated with a metal ruthenium compound to form a heterogeneous metal ruthenium catalyst.Through a series of characterization indicates the successful preparation of the catalyst.Finally,it was applied to the reaction of catalyzed alcoholysis-asymmetric hydrogen transfer in the synthesis of ?-hydroxy ester,which showed good catalytic activity and stereoselectivity,the yield can reach to 95%,and ee up to 94%,moreover,the catalyst could recovery and recycling eight times by a simple method,and no significant reduction in catalytic activity and enantioselectivity.(2): In this subject,we used mercaptopropyltrimethoxysilane,Ts-DPEN are copolymerized in alkaline solution to form a spheres-on-sphere(SOS)and then form a heterogeneous catalyst with(AreneRuCl2)2 and(CH3COO)2Pd,moreover applied to a Suzuki-Miyaura cross-coupling reaction synthetic chiral alcohols,exhibit better catalytic activity,the yield can reach to 95%,and ee up to 94%.It can be recycled seven times,and no significant reduction in catalytic activity and enantioselectivity.