可见光催化的需氧氧合反应及其相关转化研究

发布时间：2018-04-14 02:06

  本文选题：可见光催化 + 氧气活化　； 参考：《华中师范大学》2017年博士论文

【摘要】：氧气因其丰富、绿色、廉价及环境友好等自身优点,而被视为有机合成中最理想的氧化剂。基态的氧气分子一般以三线态的形式(3O2)存在,并且通常表现出较低的反应活性,而无法被直接应用到许多有机转化中。因此,对氧气的活化已经成为有机合成化学中的一个重要研究领域。近年来,可见光诱导的反应体系作为一种新型的策略已经被广泛应用于氧气活化中,并成功实现了一系列氧气参与的氧合反应。本论文对该领域的最新研究进展进行了详细的介绍,并围绕可见光催化的需氧氧合反应开展了相关研究工作。首先,我们利用可见光诱导的光氧化还原催化体系将氧气转化为超氧自由基负离子中间体,并将其应用于2,3-二取代吲哚的氧气氧化/半频哪醇重排串联反应中,在温和的反应条件下,高效、绿色地合成了一系列结构多样的2,2-二取代吲哚-3-酮类化合物。同时,我们通过O-18标记实验、荧光淬灭实验及反应中间体检测实验详细地研究了该串联反应的机理,并且我们还利用可见光催化一手性磷酸序列催化实现了该反应的不对称过程。随后,基于“优势骨架合理组合”的设计理念,我们将手性双VA唑啉骨架与光敏剂噻吨酮片段相结合,设计并合成了一类新型可见光响应的手性VA唑啉配体。并且,我们还将这类手性配体应用于可见光催化的不对称氧化轻基化反应中,以优异的产率和对映选择性合成了 一系列α-轻基-β酮酸酯类化合物。通过简单的合成转化,该产物可以用于合成高价值的手性1,2-二醇和1,2-氨基醇类化合物。同时,我们通过一系列实验对该转化的反应机理和立体诱导的模式进行了研究。另外,我们使用甲基肼与氧气原位产生双氧水的策略,实现了无金属参与的芳基硼酸的氧化轻基化反应,并以空气作为最终的氧化剂。该反应以较高的效率合成了一系列苯酚类化合物,并且表现出了较宽的底物及官能团适用范围,操作简单(室温敞口反应)等优点。同时,该反应还可以安全的扩大到克量级,并且反应的效率没有受到影响。最后,基于课题组的前期工作,我们发展了可见光催化的胺与醛/酮的自由基交叉偶联反应。该反应以廉价易得的胺和羰基类化合物为原料,高效、绿色及高原子经济性地合成了一系列结构多样的1,2-氨基醇类化合物。同时,该反应还可以扩大到克量级,或者直接使用太阳光作为光源,而反应的产率并未受到影响。
[Abstract]:Oxygen is regarded as the most ideal oxidant in organic synthesis because of its advantages such as rich, green, cheap and environmentally friendly.Oxygen molecules in the ground state usually exist in the form of triplet state and usually exhibit low reaction activity and can not be directly used in many organic transformations.Therefore, the activation of oxygen has become an important research field in organic synthesis chemistry.In recent years, the visible light-induced reaction system, as a new strategy, has been widely used in oxygen activation, and a series of oxygenation reactions have been successfully realized.In this paper, the latest research progress in this field is introduced in detail, and the related research work is carried out around the aerobic reaction catalyzed by visible light.Firstly, the oxygen was transformed into superoxide radical anion intermediate by visible light-induced photoredox catalytic system, and it was applied to the series reaction of oxygen oxidation / half-frequency alcohol rearrangement of 2o 3-disubstituted indoles.A series of 2-disubstituted indole-3-ketones with various structures were synthesized efficiently and green under mild reaction conditions.At the same time, the mechanism of the series reaction was studied in detail by O-18 labeling experiment, fluorescence quenching experiment and reaction intermediate detection experiment.Moreover, the asymmetric process of this reaction was realized by using visible light to catalyze the chiral phosphoric acid sequence.Then, based on the design concept of "reasonable combination of dominant skeletons", a novel visible-light responsive chiral VAZoline ligands were designed and synthesized by combining the chiral bis-VA azoline framework with the fragment of Guang Min.Moreover, the chiral ligands were used in the visible photocatalytic asymmetric oxidative light reaction, and a series of 伪-light-尾-ketoacid esters were synthesized with excellent yield and enantioselectivity.By simple synthesis and conversion, the product can be used to synthesize high value chiral 1o 2 diol and 1 o 2 amino alcohol compounds.At the same time, a series of experiments were carried out to study the reaction mechanism and stereoscopic induction model of the transformation.In addition, we use methylhydrazine and oxygen to produce hydrogen peroxide in situ to realize the oxidation of aryl boric acid without metal participation, with air as the final oxidant.A series of phenol compounds were synthesized with high efficiency and showed the advantages of wide application range of substrates and functional groups, simple operation (room temperature exposure reaction) and so on.At the same time, the reaction can be safely extended to the gram order of magnitude, and the efficiency of the reaction is not affected.Finally, based on our previous work, we developed a visible photocatalytic cross-coupling reaction of amine with aldehydes / ketones.In this reaction, a series of 2-amino alcohols with various structures were synthesized by using cheap and easily available amines and carbonyl compounds as raw materials, high efficiency, green and high atomic economy.At the same time, the reaction can be extended to the order of gram, or the direct use of solar light as a light source, and the yield of the reaction has not been affected.
【学位授予单位】：华中师范大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O621.251
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本文编号：1747219