Synthesis Of Chiral Ferrocene Phosphine Ligands And Their Research On Catalytic Asymmetric Hydrogenation

Due to their fascinating structure,chiral ferrocenyldiphosphine ligands play an important role in asymmetric catalysis.As a ferrocene derivative,Ugi's amine is a key intermediate during the synthesis of chiral ferrocene ligands.The Ugi's amine method allows,once the substituent at C2 has been introduced,a further stereospecific SN1-type reaction of the dimethylamino moiety with different species,which occurs with retention of configuration.So Ugi's amine is widely used in synthesis of chiral ferrocene ligand.Phosphine ligands have been the focus of research for chemists and key factors in chiral drugs or other fine chemicals synthesis because of fine catalytic activity and high stereoselectivity.However,phosphine ligands have a common disadvantage which is known as instability,so they are not easy to be stored.In order to solve this problem,we designed a new class of novel chiral ferrocenyldiphosphine ligands.The dissertation mainly focus on 3 aspects as follows: 1.The Synthesis of important intermediates(R)-the Ugi 's amineThe(R)-N,N-dimethyl amine ethyl ferrocene intermediate is prepared to ferrocene with a Simple easy low cost as the starting material after Friedel-Crafts reaction,reduction,esterification,Transamidation,chiral resolution,five-step cyclization reaction.After optimized analysis conditions,the whole experimentation avoid the method of silica gel column chromatography to obtain the target product.This route can realize industrialized production(R)-N,N-dimethyl amine ethyl ferrocene and provide plenty of chiral source to obtain a large number of chiral ferrocene ligands.The optical(R)-(+)-N,N-Dimethyl-1-ferrocenylethylamine was obtained in a total yield of 54.5%.2.The synthesis of new chiral ferrocene phosphine ligandsWe choose(R)-Ugi's amine as raw material to synthesis the four new chiral phosphine ligand L2 ?L3 ?L4 and L5.Novel chiral phosphine ligands have multiple chiral centers and higher stability compared with other phosphine ligands.And these Novel intermediates(10 a-10c)and chiral diphosphine ligand(L2-L5)by 1 H NMR?31 P NMR?Polarimeter for structural characterization.The results show that the simple and convenient route?mild conditions?the yield up to 60%.This kind of chiral ferrocene double phosphine ligands have a stable chemical properties and can be placed in the air for a long time,easy to store.3.New chiral ferrocene diphosphine ligand(L1-L5)catalytic(Z)-N-(2-ethyl-6-methyl phenyl)-1-methoxyc-2-imine(11 a)study of asymmetric hydrogenation.We selected 7 different configurations of chiral phosphine ligands,that is new chiral ferrocene diphosphine ligands and commercially available chiral diphosphine ligands as the catalyzer.And Preliminary study on the in(Z)-N-(2-ethyl-6-methyl phenyl)-1-methoxyc-2-amine asymmetric catalytic activity in hydrogenation and stereoselectivity.The chiral ligand of L3(1-S-diphenyl phosphine-2-R-di(1'1-naphthyl)phosphine ferrocene)-iridium complex obtainsexcellent reactional activity and enantioselectivity in the asymmetric hydrogenation of MEA-imine(11 a)obtain 76% ee and 99% yield.