RUI: Phosphine-Directed Carbon-Hydrogen Borylation to Access Ambiphilic Phosphine Boronates

在化学系化学催化项目的资助下，圣地亚哥大学的蒂莫西·克拉克博士正在开发金属催化反应，将碳-氢键转化为碳-硼键。这些反应是由目标分子上的磷原子（称为“磷化氢”）“引导”的。这种化学反应是不寻常的，因为碳氢键相当不活泼，没有磷化氢就不会发生这种变化。该项目的重点是利用磷化氢将金属催化剂导向分子中特定的C-H键，从而提供具有特定空间关系的化合物。通过将硼酸盐掺入这些磷化氢中，利用磷化氢和硼酸盐的互补性，形成了新的反应。克拉克小组正在获取大量的硼酸膦，并将其应用于有机化学反应中，这些反应可以促进有机分子的合成，包括与医药或能源相关的应用。克拉克博士主要与本科生合作。该项目为本科生提供研究经验，为他们在STEM领域的职业生涯做好准备。这项研究还通过提供化学合成和药物设计与开发方面的创新来促进国家利益。Timothy Clark正在开发以磷化氢为导向的C-H硼化反应，并利用由此产生的亲两性磷化氢硼酸盐进行新的有机和有机金属转化。C-H硼化反应使用独特的阳离子铱系统催化定向C-H功能化。详细的机理研究正在进行中，以进一步了解催化循环和改进系统。在这种转化中使用的膦底物被扩展到包括sp3杂化的C-H键和获得手性膦硼酸盐。所得到的膦硼酸盐在具有挑战性的催化转化中作为两亲性配体进行了研究。C-B键的进一步功能化也在探索中，以获得高功能化的磷化氢作为催化配体。除了在催化领域开发高影响力的工艺外，该资助的主要重点是指导本科生进行金属催化反应，改善这一重要化学领域的未来STEM科学家的管道。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With funding from the Chemical Catalysis program of the Division of Chemistry, Dr. Timothy Clark of the University of San Diego is developing metal-catalyzed reactions that convert a carbon-hydrogen ("C-H") bond to a carbon-boron bond. These reactions are "directed" by a phosphorus atom (called a "phosphine") on the target molecule. This chemical reaction is unusual as C-H bonds are rather unreactive and will not undergo this change without the phosphine. The focus of this project is on using the phosphine to direct the metal catalyst to a particular C-H bond in the molecule, providing compounds that have a specific spatial relationships. By incorporating boronates into these phosphines, new reactions are developed that leverage the complementary reactivity of the phosphine and boronates. The Clark group is accessing a large variety of phosphine boronates and applying them to reactions in organic chemistry that can facilitate the synthesis of organic molecules, including those of relevance to medicinal or energy-related applications. Dr. Clark works primarily with undergraduate students. This project provide undergraduate students with research experiences, preparing them for careers in STEM fields. This research also advances the national interest by providing innovation in chemical synthesis and pharmaceutical design and development.Dr. Timothy Clark is developing phosphine-directed C-H borylation reactions and using the resulting ambiphilic phosphine boronates toward new organic and organometallic transformations. The C-H borylation reaction uses a unique cationic iridium system to catalyze the directed C-H functionalization. A detailed mechanistic study is underway to further understand the catalytic cycle and improve the system. The phosphine substrates utilized in this transformation are being expanded to include sp3-hybridized C-H bonds and to access chiral phosphine boronates. The resulting phosphine boronates are being examined as ambiphilic ligands in challenging catalytic transformations. Further functionalization of the C-B bond is also being explored to access highly-functionalized phosphines as ligands in catalysis. In addition to developing high-impact processes in the area of catalysis, a primary focus of this grant is on mentoring undergraduate students in metal-catalyzed reactions, improving the pipeline of future STEM scientists in this important area of chemistry.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.