廉价金属铁类催化剂在仲醇β位直接氧化性烷基化反应中的应用

发布时间：2018-06-15 17:48

本文选题：铁 + 伯醇　；参考：《吉林大学》2014年硕士论文

【摘要】：在有机合成中，为了合成结构较为复杂的化合物，碳碳键的构成是最基本的，也是极为重要的。构成碳碳键的方法之一就是烷基化反应，而以往所用的烷基化试剂，如烷基磺酸酯、烷基卤化物等，烷基化反应后副产物较多，不符合环保性，原子利用率也较低。为此，人们开始探索活化醇作烷基化试剂，特别是活化伯醇作烷基化试剂的新型烷基化反应。但是，现在以活化伯醇作烷基化试剂的烷基化反应仍存在许多不足和缺点：1)现有方法绝大多数以稀有的贵重金属Pd、Ru、Rh、Ir等作为催化剂，这显然与当今社会所大力提倡的可持续发展战略不符；2)大多数催化剂并非市售品，而需要特制，因而不利于该方法的进一步推广与应用；3)许多方法尚需依赖复杂的含N或P配体，或者需要另行添加氢授（受）体，才能得以实现，不仅降低反应的原子利用率，，同时也增加了反应后处理的难度；4)相当多的方法还需化学计量碱的参与，对环境造成了较大影响。而活化伯醇作烷基化试剂仲醇β位直接氧化性烷基化的研究非常少，仅有两种催化剂分别为贵重金属Pd和Ag，而且Pd做催化剂时，反应中需加入大量的氢受体1-decene，还使用了化学剂量的碱；另外一种Ag类催化剂，并非市售，还需要复杂的高温活化以及氢化后方能使用。因此，在该方面对新型催化剂尤其是廉价的金属催化剂的迫切需求已经成为化学家所面临的一大问题。实验室曾首次将铁类催化剂用于活化伯醇为烷基化试剂的仲醇β位直接烷基化反应。该催化体系具有许多优点：1)首次应用廉价的铁类催化剂，且为市售；2)在催化剂量碱的作用下；3)不添加任何配体以及氢受体等，克服了以往该类烷基化反应的不足与缺点。本实验在实验室前期工作基础上，对铁类催化剂——乙酰丙酮亚铁，在活化伯醇作烷基化试剂的仲醇β位直接氧化性烷基化反应中的应用进行了深入地研究；并在研究过程发现了该催化剂在活化伯醇作烷基化试剂的仲醇β位直接烷基化反应中也颇具应用潜力。这些工作为此类烷基化反应提供了新的催化系统，为贵重的过渡金属催化剂找到了新的廉价替代品。这些研究也让我们对铁类催化剂有了进一步的认识与理解。我们首先在实验室前期研究基础上，将乙酰丙酮亚铁应用于活化伯醇作烷基化试剂的仲醇β位直接氧化性烷基化反应中，筛选出了以1-苯基乙醇与苯甲醇为底物的模型反应的最佳条件。然后对该催化系统的底物适用性进行了深入研究，得到了九种高级酮式产物，产率可达良好到优秀。本研究是首次将铁类催化剂应用于活化伯醇作烷基化试剂的仲醇β位直接氧化性烷基化反应中，同时也是首次开发出了可用于该类反应的廉价金属催化剂，为此类反应以往的贵金属催化系统找到了优良的替代品。在实验中，我们还发现在活化伯醇作烷基化试剂的该仲醇β位直接氧化性烷基化反应条件的基础上，仅需增加溶剂用量，主要产物即可由高级酮式产物逐渐转变为其所对应的高级醇式产物。并且我们还欣喜地发现，该催化系统与前述仲醇β位直接氧化性烷基化反应一样，也可以在空气氛围下进行。在此基础上，本人对其底物适用性进行了初步研究，并获得了可喜的阶段性成果。本研究工作，再次向人们展示了廉价金属，尤其是铁类催化剂，在活化醇类化合物作烷基化试剂的有机反应应用中，具有广阔的应用前景与开发潜力。本研究工作所探讨的活化伯醇作烷基化试剂的两个反应，均为单步反应，采用廉价易得金属催化剂——乙酰丙酮亚铁，使用催化剂量的碱，不需加任何氢授（受）体与配体，反应可在空气下进行。该研究极大地降低了反应成本与反应难度，原子利用率高，对环境的影响小，更加符合绿色化学和可持续发展战略的要求。通过本实验的研究进一步加深了我们对铁类催化剂的认识，也进一步地扩展了有机合成反应中铁类催化剂的应用。
[Abstract]:In organic synthesis, in order to synthesize complex compounds, the composition of carbon and carbon bonds is the most basic and extremely important. One of the methods to form carbon carbon bonds is alkylation, and alkylation reagents used in the past, such as alkyl sulfonate and alkyl halides, have more by-products and are not environmentally friendly. Therefore, people began to explore the new alkylation reaction of activated alcohols as alkylation reagents, especially activated primary alcohols as alkylation reagents.
However, there are still many shortcomings and shortcomings in alkylation reagents with activated alkyl alcohols as alkylation reagents: 1) most of the existing methods use rare precious metals as Pd, Ru, Rh, Ir as catalysts. This is obviously inconsistent with the sustainable development strategy advocated by today's society; 2) most of the catalysts are not marketable, but need special. It is unfavorable to further popularization and application of this method; 3) many methods still need to rely on complex N or P ligands, or the need to add hydrogen (acceptor) body to be realized, not only to reduce the atomic utilization of the reaction, but also to increase the difficulty of the reaction after the reaction. (4) a considerable number of methods also require the participation of the stoichiometric base. There is a great influence on the environment. But the study of activated primary alcohol as an alkyl reagent is very rare. Only two kinds of catalysts are precious metals Pd and Ag, and when Pd is used as catalyst, a large amount of hydrogen receptor 1-decene is added to the reaction, and the chemical dose of alkali is also used; the other kind of Ag catalyst, It is not sold in the market, but also requires complex high temperature activation and the use of hydrogen in the rear. Therefore, the urgent need for new catalysts, especially cheap metal catalysts, has become a major problem for chemists.
The laboratory has used the iron catalyst for the first time to activate primary alcohols as alkylation reagents for secondary alkylation of secondary alcohols. The catalytic system has many advantages: 1) the first use of cheap iron catalysts, and the market for sale; 2) not adding any ligands and hydrogen receptors under the action of the catalyst; 3) to overcome the previous alkane On the basis of early laboratory work, the application of the iron catalyst, acetyl acetone, in the direct oxidative alkylation of secondary alcohols of activated primary alcohols as alkylation reagents, was deeply studied, and the catalyst was alkylated in activated primary alcohol. The reagents also have potential applications in the direct alkylation of secondary alcohols, which provide new catalytic systems for such alkylation, and have found new cheap alternatives for the valuable transition metal catalysts. These studies have also given us a further understanding and understanding of the iron catalysts.
On the basis of preliminary laboratory studies, the optimum conditions for the model reaction with 1- phenyl ethanol and benzyl alcohol as substrates were screened in the direct oxidation alkylation of secondary alcohols from activated primary alcohols to alkyl alcohol as alkylation reagents. Then the substrate suitability of the system was deeply studied. Nine kinds of advanced ketones are obtained. The yield is good to excellent. This study is the first time to use the iron catalyst in the alkylation of activated beta alcohol as an alkyl agent for the alkylation of secondary alcohols. It is also the first time to develop a cheap metal catalyst for this kind of reaction. The chemical system has found a good substitute.
In the experiment, we also found that on the basis of the direct oxidative alkylation of the secondary alcohols of activated primary alcohol as an alkylation agent, only the amount of solvent was needed, and the main product was gradually transformed from the advanced ketone product to its corresponding high alcohol product. On the basis of this, I have made a preliminary study on the applicability of the substrate and obtained the gratifying stage results. In this study, the cheap metals, especially the iron catalysts, were shown to the alkylation of activated alcohols. The organic reactions of the agents have broad application prospects and development potential.
The two reactions of activated primary alcohols as alkylation reagents are a single step reaction, using a cheap and readily available metal catalyst, acetyl acetone, and the use of a catalyst amount of alkali, without the addition of any hydrogen (acceptor) body and ligand, and the reaction can be carried out in the air. This study greatly reduced the reaction cost and difficulty of reaction. The high efficiency of atomic utilization and less influence on the environment is more in line with the requirements of the strategy of green chemistry and sustainable development. Through this study, we have further deepened our understanding of the iron catalyst and further expanded the application of the iron catalyst in the organic synthesis reaction.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R914

【共引文献】