The Research Of Reactions Of Ketones With Organometallic Reagents Promoted By Anhydrous Cerium(Ⅲ) Chloride

The nucleophilic addition of a Grignard reagent or organolithium compound to the carbonyl group is a wide applied reaction,but some hindered ketones are hard to react with Grignard reagents or organolithiums.Even no products are gained.This thesis aims to study two kinds of ketones(PhCOFc,FcCOFc) react with some organometallic reagents(CH₃MgI,CH₃CH₂MgBr,(CH₃)₂CHMgBr,CH₃(CH₂)₃MgBr, PhMgBr,FcLi) in the presence of anhydrous cerium(â…¢) chloride or not.The influence of different amounts of organic halides toward the yield was also discussed. All products were characterized by elemental analysis,IR,¹H NMR spectra.In conclusion,The use of anhydrous CeCl₃ enhanced the yields of the addition products of different organometallics to ketones.Especially in the reactions of diferrocenylmethanone,no products were obtained with Grinard reagents alone;in the presence of cerium(â…¢) chloride,the yields of reactions of CH₃CH₂MgBr and CH₃(CH₂)₃MgBr were above 90%,the yields of reactions of other organometallic reagents were also enhanced.The reaction time shortened in the presence of cerium(â…¢) chloride,ca.30 min.Without cerium(â…¢) chloride the reaction needs higher temperature and longer reaction time.In experiment,when Grignard reagents made from magnesium of low purity react with diferrocenylmethanone in high temperature,tetraferrocenylethylene is obtained in high yield.This coupling reaction is suppressed and only the corresponding alcohol is gained in the presence of cerium(â…¢) chloride.