Organosilanols as Universal Donors in Organometallic Chemistry

在这个由化学系化学催化计划资助的项目中，斯科特·E·丹麦教授将进行研究，以实现使用有机硅醇来获得大量过渡金属元素的催化有机金属化学。有机硅醇是一种价格低廉、无毒、对空气和水稳定的化合物，它们通过离散的Si-O-M键与许多其他碳-金属键交换碳-硅键，具有非凡的能力。该计划将对镍、铜、铑、铱和铬衍生的过渡金属硅烷酸酯的合成、反应活性和随后的催化化学进行合理的、基于结构的探索。研究计划的第一部分将涉及对已建立的、钯催化的硅烷酸酯交叉偶联反应的催化循环中基本步骤的详细机械解析。这些见解将对涉及其他研究较少的过渡金属的研究计划的主要主旨具有重要价值。大部分研究计划将涉及探索硅醇(硅醇酸盐)与现有催化活性中间体形成Si-O-M键或在过渡金属试剂的反应中生成这些中间体的能力。在许多情况下，这种过渡金属硅酸盐络合物可以独立制备和研究，而在其他情况下，将需要原位生成和产物分析。化学合成所有领域的进步都是由新化学反应的创造、优化和理解推动的。制备具有挑战性化学结构的分子(天然产物或具有理论意义的分子)或具有理想的化学、物理或生物特性的分子(在材料科学或农业、制药或商业领域的应用)将需要有能力设计可执行的合成路线。从20世纪下半叶有机合成的演变中得到的最重要的教训是，合成路线的战略和规划是由战术驱动的。换句话说，化学合成的范围、选择性和效率与新化学反应的发现、发展和优化密不可分。该项目将开展的这些活动是对研究生和博士后同事进行智力和实践培训的理想选择。反应设计、开发和应用的相互作用代表了科学方法的精髓。学生将被提出关于计划实验结果的假设，他们必须学会收集和解释数据以证实或消除假设。这项活动的统一主题将是在现有机制范例的基础上发明新的化学反应。这将在该项目的指导方针内为学生提供一个创造性的平台，让他们确定新的方向。此外，从廉价、无毒、空气和水稳定的硅烷酸酯中可以获得的新型碳-碳键形成过程的多样性将是重要的。

In this project funded by the Chemical Catalysis Program of the Chemistry Division, Professor Scott E. Denmark will conduct research to implement the use organosilanols to access the catalytic organometallic chemistry of a myriad of transition metal elements. Organosilanols are inexpensive, non-toxic, air- and water-stable compounds that have the remarkable ability to exchange the carbon-silicon bond with many other carbon-metal bonds through the agency of a discrete Si-O-M linkage. The program will involve a rational, structurally-based exploration of the synthesis, reactivity and subsequent catalytic chemistry of transition metal silanolates derived from nickel, copper, rhodium, iridium and chromium. The first component of the research plan will involve detailed mechanistic resolution of the elementary steps in the catalytic cycle for the well-established, palladium-catalyzed, cross-coupling reactions of silanolates. These insights will be of great value for the major thrust of the research plan that involves other, less well-investigated transition metals. The bulk of the research program will involve the exploration of the ability of silanols (silanolates) to form Si-O-M linkages with existing catalytically active intermediates or to create those intermediates in the reactions of transition metal reagents. In many cases, such transition metal silanolate complexes can be independently prepared and studied, whereas in other cases, the in-situ generation and product analysis will be needed. Progress in all areas of chemical synthesis is driven by the creation, optimization and understanding of new chemical reactions. The preparation of molecules with challenging chemical structures (natural products, or molecules of theoretical interest) or molecules with desirable chemical, physical or biological properties (with applications in materials science or the agricultural, pharmaceutical or commercial sectors) will require the ability to design executable synthetic routes. The most important lesson gleaned from the evolution of organic synthesis during the second half of the 20th century is that strategy and planning of synthetic routes is driven by tactics. In other words, the scope, selectivity and efficiency of chemical synthesis are inexorably tied to the discovery, development and optimization of new chemical reactions. These activities to be carried out in this project are ideal for the intellectual and practical training of graduate students and postdoctoral coworkers. The interplay of reaction design, development and application represent the essence of the scientific method. Students will be presented with hypotheses for the outcome of planned experiments and they must learn to collect and interpret data to substantiate or eliminate the hypothesis. The unifying theme of this activity will be the invention of new chemical reactions on the basis of current mechanistic paradigms. This will provide a platform for creativity within the guidelines of the project for students to identify new directions. In addition, the diversity of new types of carbon-carbon bond forming processes that will be accessible from inexpensive, non-toxic, and air and water stable silanolates will be significant.