Synthesis Of A Novel Type Of Zirconium Phosphonates-Supported Cinchona Alkaloid Catalysts And Their Application In The Asymmetric Catalysis

Due to the fine stereoscopic skeletons,Cinchona alkaloids demonstrate very good catalytic activity in the asymmetric catalysis.The supported-cinchona alkaloid catalysts with organic polymer,silica gel,merrifield resin and macromolecule compound etc are reported.The design and synthesis of a novel type of zirconium phosphonates-supported cinchona alkaloid,which have a different organic arms length,are mainly discussed in this dissertation.The asymmetric addition of diethylzinc with benzaldehye catalyzed by zirconium phosphonates-supported cinchona alkaloid catalysts is also discussed in detail.A series of organic zirconium phosphonates-supported cinchona alkaloid catalysts,with a different organic arms length,are synthesized by several steps:Michaelis-Arbuzor,nuclear substitation,free radical addition,and hydrolysis reaction using a kind of configuration of cinchona alkaloids-cinchonidine as starting material.In order to obtain the support of cinchona alkaloids,four different synthetic routes are explored and studied successfully.Five zirconium phosphonate-supported cinchona alkaloid catalysts 4a～e are synthesized.The structure and morphorlogy are characterized by using FT-IR,TG,XPRD,N₂-sorption,SEM, elemental analysis and TEM.The chemical composition of the catalysts are confirmed.In the asymmetric addition reaction of diethylzinc with benzaldehyde,the effect of organic arm length of organic moieties on the catalytic properties is investigated.The 54-72%yield and 10-25%ee enantioselectivity are obtained by using zirconium phosphonates-supported cinchona alkaloid catalyst 4a～e.Zirconium phosphonates-supported cinchona alkaloid 4e exhibited the best catalytic properties,which was attributed to the longest organic arm length.The optium catalytic conditions are concluded that the molar ratio of benzaldehyde to diethylzinc was 1 to 2,and 15 molar percent of catalyst was used in toluene/hexane（v/v=1:1）,and stirred for 72 h at room temperature.