Developing Novel Triazole-Ruthenium Carbene Complexes (TA-Ru) for Challenging Olefin Metathesis Transformations

在化学系化学催化项目的支持下，马里兰大学学院园区的石晓东教授正在开发一种新型催化剂，使具有挑战性的烯烃歧化转化能够发生。烯烃歧化反应是形成新的碳-碳双键的重要化学反应。虽然复分解转化被用于化学、材料和生物研究，但目前的催化剂面临着更多需要高温的分子和反应的挑战。相比之下，施教授和他的团队正在开发的新催化剂在较高温度下的稳定性显著提高。因此，这些新的催化剂能够合成新的化学结构，而这些结构是目前的复分解催化剂系列无法获得的。这些新型分子催化剂将应用于许多问题，不仅将促进基础化学研究，还将影响其他依赖复分解产物的科学领域和行业，如生物技术和制药行业、化学和材料科学界/行业。除了提高复分解在几个科学领域的适用性外，这些研究还将通过为本科生和研究生提供重要的化学合成培训和组织面向学生的会议来支持下一代科学家的准备。Ru-Carbine复分解催化剂在合成化学中广泛应用。虽然Ru催化剂通常表现出良好的反应活性和对官能团的耐受性，但随着时间的推移，它们会分解和/或受到热不稳定性的影响。石晓东教授和他的研究小组发现，容易获得的三氮唑配体赋予了Ru-卡宾催化剂稳定性，从而在烯烃歧化反应中提供了新的反应活性。这些新催化剂将针对以前报道的催化剂难以进行的转化进行优化。为了更好地了解三氮唑基序的作用，还将进行机理研究。此外，还将进行补充的合成研究，以将最初的催化产品转化为对化学生物学和药物和材料化学有用的增值合成目标。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Catalysis Program in the Division of Chemistry, Professor Xiaodong Shi of the University of Maryland-College Park is developing a new class of catalysts that enable challenging olefin metathesis transformations to occur. Olefin metathesis is an important chemical reaction that results in the formation of new carbon–carbon double bonds. While metathesis transformations are being employed in chemical, materials, and biological research, current catalysts are challenged by more those molecules and reactions that require high temperatures. In contrast, the new catalysts that are being developed by Professor Shi and his team show significantly improved stability at higher temperature. As a consequence, these new catalysts enable the synthesis of novel chemical structures that are not accessible using the current suite of metathesis catalysts. These new molecular catalysts will be applied to a number of problems and will not only advance fundamental chemical research but will also impact other scientific areas and industries that rely on the products that come from metathesis, e.g. biotech and pharmaceutical industries, the chemical and material science communities/industries. In addition to advancing the applicability of metathesis across several areas of science, these studies will support the preparation of the next generation of scientists by providing undergraduate and graduate students important training in chemical synthesis and through the organization of meetings that are student-oriented.Ruthenium-carbene metathesis catalysts are broadly applicable in synthetic chemistry. While ruthenium catalysts generally show good reactivity and functional group tolerance, they decompose over time and/or they suffer from thermal instability. Professor Xiaodong Shi and his research group have discovered that readily available triazole ligands impart stability on Ru-carbene catalysts and consequently provide novel reactivity when applied to olefin metathesis reactions. These new catalysts will be optimized for transformations that have been difficult to carry out using the previously reported catalysts. In efforts to better understand the role of the triazole motif, mechanistic studies will also be pursued. In addition, complementary synthetic studies will be pursued to convert the initial catalytic products to value-added synthetic targets that will be useful for chemical biology and medicinal and materials 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.