Research On S_NV Of3-Nitromethylene-Isatins And Organocatalyzed Inversed Electron-Demand Diels-Alder Reaction

This thesis focused on the application of simple inorganic or organic reagents on complex transformations and the synthesis of active compounds, such as inorganic salts-prompted reactions and its application, metal-catalyzed transformations, the application of metal-complex as catalyst, and so on, which were described in three chapters:base-mediated nucleophilic vinylic substitution (SnV) of nitroolefins to form verious3-substituted oxindoles (3-derivatived isatins), thiourea-catalyzed asymmetric inversed electron-demand Diels-Alder reaction (IEDDAR), bifuncational Lanthanide-complex catalysts and its application in IEDDAR.Chapter Ⅰ:Review on Nucleophilic Vinylic SubstitutionThe reactions of nucleophilic vinylic substitution were reviewed and classificated by nucleofuge, such as halogen as nucleofuge, nitro as nucleofuge, other nucleofuges and organocatalyzed SNV. The mechanism was discussed, too.Chapter Ⅱ:The SNV of3-Nitromethylene OxindolesReactions prompted by simple inorganic salts or base are convenient and have low costs, so are very versatile. Oxindole moieties are very versatile units of drugs and bioactive compounds. Herein a metal-free coupling reaction was described for the formation of oxindoles via a new nucleophilic vinylic substitution (SNV) of nitroolefins by using the nitro group as a nucleofuge, which proceeded through a Micheal addition/1,2-cis-elimination process. Such nucleophiles as alcohols, phenols, amines and thiols even β-ketoester worked in this SNV reaction, formed C-O, C-N, C-S and C-C bonds, and afforded oxindoles correspondingly with good to excellent yields and stereoselectivities.Chapter III:The Chiral Thiourea-Catalyzed Tandem IEDDAR/retro-Henry and Its New MechanismThioureas become interested catalysts for their good hydrogen bond in N-H, which can also perform asymmetric tansformations when the N-substitution is a chiral part. Diels Alder reactions got continuous attention for its high efficiency on the construction of rings. Tandem reaction also got very wide interests for its wide application in the formation of functional group even molecular skeletons.A direct asymmetric tandem reaction of α-nitro ketones with β,γ-unsaturated α-ketoesters was found to be catalyzed by a bifunctional rosin-derived thiourea and gave5-nitro-2-actoxyl-2-pentenates in excellent ee values and yields, a much better result than the previously reported. Furthermore, through theoretical analysis, literature research and experimental verifications, a new mechanism involving an inverse-electron-demand Diels-Alder (IEDDAR) and a retro-Henry reaction was proposed.Chapter Ⅳ:Chiral Bifunctional La-Complex Catalyzed IEDDARLanthanide salt has Lewis acid’s properties, so is a kind of widely used catalyst. In the complex formed from lanthanide slat, binol and strong base, the lanthanide metal kept its lewis property and the oxo-anion formed from the reaction of binol and base has basic property, so the complex has both acidic and basic funcation and can be used as bifunctional catalyst. Bifunctional catalysts are famous and aroused wide attention for its high efficiency and stereoselectivities, which activiated two reactive sites instantaneously. This kind of catalysts has been applied in various reactions. Amongst La-complex formed from La-salts, chiral ligands and strong bases. This chapter mainly focused on the application of this kind of catalyst in various IEDDAR reactions, which is still in progress.