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3-硝基烯键氧化吲哚的S_NV反应和有机催化的电子反转D-A反应研究
Research on S_NV of3-Nitromethylene-Isatins and Organocatalyzed Inversed Electron-Demand Diels-Alder Reaction
【作者】 张虹锐;
【导师】 唐瑜;
【作者基本信息】 兰州大学 , 无机化学, 2014, 博士
【摘要】 本论文的工作着重于将简单的无机、有机试剂应用于复杂的化学转化和复杂结构的合成中,比如,无机盐或者碱促进的化学反应,金属催化的化学反应(比如,Pd-C催化氢化,钯金属催化羰基化等),金属配合物作为催化剂的应用,以及这些反应作为关键步骤合成一些复杂化合物,等等,本论文的工作共包括三个方面:碱促进的3-硝基烯键氧化吲哚(3-位衍生的靛红)的烯键上的亲核取代反应(SNV)研究,手性硫脲催化的电子反转的Diels-Alder反应(IEDDAR)研究,镧系金属配合物作为双功能催化剂催化的IEDDAR反应研究。第一章:烯键上的亲核取代反应研究进展(综述)我们对于各种杂原子取代的烯烃在亲核试剂作用下杂原子被取代的反应进行了综述。我们分别对卤素作为离去基的、金属参与的、邻基参与的、硝基作为离去基的、以及其他官能团作为离去基的烯键上的亲核取代反应和有机分子催化的烯键上亲核取代反应进行了探讨,并对反应的机理和特点进行了讨论。综述发现,硝基作为离去基的烯烃加成-消去(SNV)反应研究很少,而且氧化吲哚类底物的SNV反应尚未见报道。第二章:3-硝基烯键氧化吲哚的烯键上的SNV反应简单的无机盐或者碱能够促进的反应通常都由于其简洁、低成本而具有十分重要的应用价值。氧化吲哚是非常重要的药物和天然活性化合物的结构单元。本章发现简单的无机盐、碱或者有机碱可以促进3-硝基烯键氧化吲哚化合物发生SNV反应,从而生成一系列3-位多种取代类型的氧化吲哚衍生化合物。该反应是用硝基作为离去基、通过烯键上的亲核取代反应进行的,研究发现其机理是先加成-后消去,加成是1,2-反式加成,消除则是1,2-顺式消除。这里的亲核试剂包括醇、酚、胺以及硫醇乃至p-酮酸酯,它们与一系列的3-硝基烯键衍生的氧化吲哚反应,可以生成3-位各种取代的氧化吲哚化合物。该反应条件简单,试剂易得,有很好的收率和立体选择性。第三章:手性硫脲催化IEDDAR/retro-Henry串联反应硫脲分子由于其N-H上的氢原子容易形成氢键而成为一种热门催化剂,尤其是其N-取代的手性片段可以帮助实现不对称的催化反应而备受青睐。D-A反应由于其构环的高效性,成为人们长期关注的对象。串联反应也由于在官能团的形成甚至分子骨架构筑方面无可比拟的高效率也成为近些年化学家争相研究的对象。α-硝基酮和β,γ-不饱和的α-酮酸酯在双功能松香胺-硫脲-奎宁催化剂催化下以很高的ee值和收率生成了5-硝基-2-乙酰氧基-2-戊烯酸酯,反应的立体选择性和收率都比之前报道的类似反应高。而且,通过理论分析、文献调研和实验验证,我们提出了一个新的反应机理,和之前的Micheal加成-缩酮化-retroHenry的串联反应相比,我们认为该反应更有可能是通过烯醇化-电子反转的Diels-Alder反应-retroHenry的串联反应。第四章:手性双功能镧系金属催化剂催化的IEDDAR反应。镧系金属形成的化合物具有Lewis酸的性质,是一类用途广泛的催化剂。它和Binol以及强碱形成的配合物中镧系金属作为中心配位原子保留了其Lewis的性质,而强碱和Binol形成的外围氧负离子又可以作为碱来用,因而它们的配合物就有酸碱两重功能,是很好的双功能催化剂。这样的双功能催化剂由于可以同时催化两个反应位点,大大提高了反应的效率和立体选择性,在多种反应中表现出很好的效果,但是它们在电子反转的D-A反应中应用较少。本章把这样的催化剂应用于多种类型的电子反转的D-A反应中,并和第三章所用的有机分子双功能催化剂进行比较,顺利得到预期的关环产物,但是收率和立体选择性上需要进一步优化。相关的深入研究正在进行。该工作将进一步拓展镧系金属的用途,也是首次将镧系金属用于D-A反应中。
【Abstract】 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.