Thiourea Cataiyzed Enantioselective Electrophilic Fluorination Of β-Ketoesters And Asymmetric Michacl Addition Of1,3-Dicarbonyl Compounds To β-Nitroolefins

The chemistry of organofluorine compounds has attracted more and moreattention in recent years because of their increasingly important role in medicinalchemistry and material science. One of the most fascinating aspects of organofluorinechemistry is the asymmetric synthesis of fluorinated molecules, Thus, variousmethods for asymmetric incorporation of a fluorine atom into organic molecules havebeen developed, Among these procedures to produce enantiopure organofluorinecompounds, catalytic enantioselective fluorinations provide one of the most powerfulsynthetic methods. However, there is no report on enantioselective fluorinationreactions using chiral thioureas as organocatalysts although such thiourea-basedorganocatalysts have proved to be remarkably useful organic catalysts in variousasymmetric reactions. Herein we explore firstly that chiral thioureas are very effectivecatalysts in enantioselective fluorination reactions.The paper consists of three parts:The first chapter: Research Progress in Enantioselective ElectrophilicFluorinationsThis chapter mainly elaborats on the developments of enantioselectiveelectrophilic fluorinations reaction from three aspects: first, enantioselectiveelectrophilic fluorinations reaction with an chiral fluorinating agent as the inducement;Second, enantioselective electrophilic fluorinations reaction with metal complex asthe catalyst; Third, enantioselective electrophilic fluorination reaction with smallorganic molecules as the catalyst.The second chapter: Chiral Thiourea-Catalyzed Enantioselective ElectrophilicFluorination of-Keto EstersBifunctional chiral thioureas have been used for the first time in theenantioselective electrophilic fluorinations reaction. The enantioselective electrophilicfluorination of-Keto Esters was investigated firstly and the products were obtainedin up to92%yield and99%ee. Enantioselective fluorination of α-Cyano Esters andOxindole Derivatives were also explored. When the oxindole derivative was used as substrate, the ring-opening fluorinated product was obtained in ee value of92%withlow yield of30%.The third chapter: Asymmetric Michael Addition Reaction of1,3-DicarbonylCompounds to-Nitroolefins Catalyzed by Chiral ThioureasThe Michael addition is one of the most frequently used C C bond-formingreactions in organic synthesis. In recent years, asymmetric Michael addition reactionresearch has developed mature, however, organocatalytic conjugated additions usingaromatic ketones (1,3-Diphenyl-1,3-propanedione) as the Michael donor are rarelystudied. This chapter explore that Cinchona alkaloids-Chiral Thiourea catalyzedAsymmetric Michael Addition Reaction of1,3-Diphenyl-1,3-propanedione toNitroolefins and obtained the high yield and ee value.