Application Of Novel Spiro-Pyrrolidine(SPD)-Derived Thiourea Catalysts In Asymmetric Catalysis

Spirocyclic carbon framework plays an important role in the field of organocatalysis because of their unique rigid structure.The spiro-pyrrolidine(SPD)catalysts have shown promising catalytic activity in reactions to achieve excellent stereoselectivity,high efficiency and universality.Therefore,the design and synthesis of novel SPD catalysts with an attempt to enable novel asymmetric structural motif which contains such chemical reactions have become a prolonged research topic in the field of organic chemistry.Our group has been devoted to the development and application of SPD catalysts including SPD organo catalysts and ligands that are easily prepared by semipinacol rearrangement reaction and continuously applied in various asymmetric catalytic reactions.In this thesis,an SPD derived thiourea catalyst was prepared and applied to the remote conjugate addition reaction of β,γ-unsaturated α-ketoesters and 5-benzylfurfural derivatives with excellent diastereo and enantioselectivities obtained.Specifically,this paper is divided into two parts:Part Ⅰ: The research background of the spirocyclic organo catalysts and the synthesis and application of spiro-pyrrolidine catalysts in recent years are introduced in detail.The research background of thiourea catalysts in asymmetric reactions is introduced with an emphasis of the design and synthesis of SPD thiourea catalysts.Part Ⅱ: The research background of asymmetric addition reaction catalyzed by thiourea is introduced.The asymmetric conjugate addition reaction of5-benzylfurfurals with β,γ-unsaturated α-ketoesters catalyzed by SPD thiourea catalyst is designed,which was used in the remote conjugate addition of5-benzylfurfurals and β,γ-unsaturated α-ketoesters.The substrate scope of the reaction and its gram scale preparation was also investigated.