Advancing Late Metal Catalysis: DalPhos Ligand Design, Mechanism, and New Reactivity

金属基催化剂在促进化学反应中发挥着核心作用，这些化学反应产生了我们日常生活中使用的分子和材料（例如燃料，塑料，药物等）。在这方面，允许将廉价和丰富的试剂分子转化为感兴趣的增值产品的新型催化剂的开发代表了现代学术和工业研究中的重要和持续的挑战。特别令人感兴趣的是识别催化剂，使有用的化学转化，目前不可能通过任何其他手段。该提案的目标是合理开发新型金属基催化剂，以实现极具挑战性的反应，将廉价和丰富的小分子，包括氨，肼和羟胺，以高效和更环保的方式转化为有用的产品，直接应用于制备药物和下一代发电设备。所研究的金属基催化剂基于申请人的研究小组开发的现在商业化的“DalPhos”（达尔豪西PHOSphine）配体;这些表现出显著的催化行为，其不同于大多数其他已知的催化剂类型，但我们对这种行为的理解非常有限。作为回应，我们将寻求通过DalPhos配体结构的战略多样化/优化以及催化剂筛选来利用和增强DalPhos基金属催化剂的独特行为，目标是获得我们可以详细研究其作用模式的优化结构。然后，优化的DalPhos催化剂将用于解决上述具有挑战性的反应类型。这些合成、结构、机理和催化研究将拓展我们对金属催化反应中连接效应的概念性理解，并为新药和功能材料的开发提供实际的方法。

Metal-based catalysts play a central role in promoting chemical reactions that give rise to the molecules and materials that we make use of in our everyday lives (e.g. fuels, plastics, medicines, and other). In this regard, the development of new classes of catalysts that allow for the conversion of cheap and abundant reagent molecules into value-added products of interest represents an important and ongoing challenge in modern academic and industrial research. Of particular interest is the identification of catalysts that enable useful chemical transformations that are not currently possible by any other means. This proposal targets the rational development of new classes of metal-based catalysts to enable extremely challenging reactions that convert cheap and abundant small-molecules, including ammonia, hydrazine, and hydroxylamine, into useful products in an efficient and more environmentally friendly manner, with direct applications in the preparation of pharmaceuticals and next-generation power-generating devices. The metal-based catalysts under investigation build upon what are now commercialized “DalPhos” (DALhousie PHOSphine) ligands developed in the applicant’s research group; these exhibit remarkable catalytic behavior that is distinct from most other known catalyst types, but our understanding of this behavior is very limited. In response, we will seek to harness and augment the unique behavior of DalPhos-based metal catalysts via strategic diversification/optimization of the DalPhos ligand structure followed by catalyst screening, with the goal of obtaining optimized structures that we can study in detail regarding their mode of action. Optimized DalPhos catalysts will then be applied toward addressing the challenging reactivity types listed above. The proposed synthetic, structural, mechanistic, and catalytic studies will expand our conceptual understanding of ligation effects in metal-catalyzed reactions, as well as providing practical in-roads to new medicines and functional materials.