【作者】 陈红；

【导师】 雷爱文； 张恒；

【作者基本信息】 武汉大学 ， 有机化学， 2019， 硕士

【摘要】 光催化交叉偶联反应作为一种高效的各类碳碳、碳杂键的绿色合成手段,在过去的十几年间吸引了大量专家学者的研究兴趣,并且取得了令人瞩目的研究成果。在这之中,光催化氧化偶联放氢反应以其高原子经济性、反应条件温和且无需牺牲氧化剂即可高效发生的优势成为有机合成领域中倍受青睐的研究方向。咪唑并吡啶作为一种多元氮杂环骨架,在药物化学领域有着广泛的应用。该骨架C3位置的选择性C-H键官能团化对其药理活性有着显著影响。本论文第一章中介绍了我们通过结合光催化剂和钴肟产氢催化剂,实现了咪唑并吡啶杂环以及苯并噻唑并咪啶杂环的C3位选择性C-H键活化胺化反应,此反应体系对各类取代的底物均能得到不错的产率。此外,我们也通过开关灯实验、循环伏安实验以及理论计算方法对反应机理进行了一定的探究。二价铜作为一种廉价低毒的过渡金属,因其独特的反应性质,在有机化学合成领域中有着极其重要的作用。三苯基膦作为配体在很多金属催化体系中都有着重要的应用。磷配体与金属之间的作用机制虽有一些报道,但这些报道也鲜有证据支撑。本论文第三章介绍了我们对二价铜与三苯基膦的反应过程进行的机理研究。我们通过同步辐射手段确定金属氧化态及其配位环境,通过在线紫外-可见吸收光谱以及EPR实验对反应过程进行了一定的探究,并根据实验结果提出了可能的反应机理。更多还原

【Abstract】 Photocatalysis is an effective method for constructing new molecules.With the development of photocatalysis,visible light-mediated photoredox process has attracted wide attention,and gradually developed as a very powerful tool for green synthesis.Especially,photoredox cross-coupling hydrogen evolution(CCHE)reaction is a powerful method to construct C-C and C-X bonds,which has no by-products except hydrogen,mild reaction conditions and no external oxidants.Imidazopyridine,as a multi-component azacyclic framework,has been widely used in the field of pharmacochemistry.The selective C-H bond functionalization at the C3 position of the skeleton has a significant effect on its pharmacological activity.In the first chapter of this paper,we introduced selective C-H bond activation amination at the C3-site of imidazopyridine heterocycles and benzothiazole-imidine heterocycles by combining photocatalysts with hydrogen-producing catalysts.The reaction has wide applicability to substrates and mostly can obtain very good yields.In addition,we also studied the reaction mechanism by light on/off experiment,cyclic voltammetry experiment and theoretical calculation method.As a cheap and low toxic transition metal,copper plays an extremely important role in organic synthesis due to its unique reaction properties.Triphenylphosphine has important applications in many metal catalytic systems working as ligand.Although the mechanism of interaction between phosphorus ligands and metals was proposed in some reports,there is little evidence to support their mechanism.In the third chapter of this paper,we investigated the mechanism of the reaction between copper(II)and triphenylphosphine.The oxidized state of copper and its coordination environment were determined by synchrotron radiation.The reaction process was investigated by in-situ UV-Vis absorption spectroscopy and EPR experiments.The possible reaction mechanism was proposed based on these experimental results.更多还原