Asymmetric Organocatalytic Cascade Reactions For The Synthesis Of Tetrahydroquinolines, Chromans And γ-Lactone Derivatives

This thesis is mainly engaged in asymmetric organocatalytic cascade reactions for synthesis of heterocyclic compounds, mainly includes the following five parts.Asymmetric organocatalytic cascade reactions have been established as a powerful and efficient tool for the repaid assembly of complex structures from simple and readily available starting materials in a single process. Development of new types of asymmetric organocatalytic cascade reactions is an important goal of reaction carried out in both academic and industrial laboratories. This chapter is review the recent advance of asymmetric organocatalytic cascade reactions to build heterocyclic compounds.Tetrahydroquinoline derivatives are an important class of heterocycles and the tetrahydroquinoline ring system occurs in various natural products and pharmaceuticals, which have shown a wide range of biological activities. We have developed a novel synthetic method for polysubstituted tetrahydroquinoline derivatives via organocatalytic asymmetric cascade Michael/aza-Henry reaction through easily prepared chalcone and nitroalkane as the starting materials. Substituted tetrahydroquinolines were given in high yields and excellent enantioselectivities. Moreover, through a simple transformation, the product could successfully synthesize the tricyclic core compound.In our previous work, we can get polysubstituted tetrahydroquinoline derivatives via organocatalytic asymmetric cascade Michael/aza-Henry reaction. Such reactions yield cis-isomers at the2,3-positions. In our effort to further explore the synthesis of quinolones with diverse structural features, we develop an efficient and highly enantioselective synthesis method for polysubstituted tetrahydroquinoline via cascade aza-Michael-Michael reactions. Reactions get the trans-isomers at the2,3-positions. These methods allow for the preparation of substituted tetrahydroquinolines with diverse stereochemical features.It is well known that chiral chroman and benzopyran structures belong to an important class of heterocycles, which possess an extensive array of biological activities. We have developed a highly enantioselective cascade double Michael reactions for synthesis of chiral chromans in good yields and excellent enantioselective from the simple and readily available starting materials using the commonly available bifunctional organocatalysts. The product can easily transform to the tricyclic core compound.N-Heterocyclic carbene catalysts are a new type of organic catalysts. It can not only coordinate with metal as ligands, but also catalyze the organic reactions directly. We found a new N-Heterocyclic carbene catalyst to catalyze the enantioselective enal dimerization. γ-lactone could get in good yield and excellent enantioselective.