New strategy for ruthenium olefin metathesis catalysts using dianionic tridentate ligands

烯烃复分解已成为合成化学家制造碳-碳双键的强大工具。这种转变是通过使用金属碳催化剂实现的，对新材料（聚合物/塑料）和有机化合物，包括具有生物活性的材料（药物）的发展产生了显著影响。这个反应的重要性反映在2005年授予Chauvin， Schrock和Grubbs的诺贝尔化学奖上。虽然在过去的几十年里取得了显著的进展，但钌基催化剂的热稳定性及其对各种反应物（也称为底物）和转化的良好选择性仍然是一个问题。例如，较差的热稳定性会导致这些催化剂在反应过程中分解，从而降低生产率。此外，催化剂的选择性差导致产物的混合物难以以其纯形式分离。这对具有生物活性的化合物尤其重要，因为副作用污染物会引起严重的副作用。

Olefin metathesis has become a formidable tool for synthetic chemists to create carbon-carbon double bonds. This transformation, made possible by the use of metal carbene catalysts, has had a remarkable influence of the development of new materials (polymers/plastics) and organic compounds, including those with biological activity (drugs). The importance of this reaction is reflected in the 2005 Nobel Prize in Chemistry awarded to Chauvin, Schrock and Grubbs. Although remarkable progress has been made in the past decades, the thermal stability of ruthenium-based catalysts and their ability to achieve good selectivity for a wide range of reactants (also known as substrates) and transformations still remain an issue. For instance, poor thermal stability results in decomposition of these catalysts over the course of the reaction with a decrease in productivity. Furthermore, poor selectivity of the catalyst leads to mixtures of products that can be difficult to isolate in their pure form. This is especially concerning for biologically-active compounds where side-product contaminants can cause severe undesired side effects. A strategy to develop new catalysts capable of mediating olefin metathesis is presented in the proposal. The approach leverages observations made by the Lavoie group and by others in the field. Catalysts with building blocks that can easily be modified are proposed and used to modulate the performance of these catalysts in olefin metathesis. The initial focus of the research is aimed at producing thermally robust catalysts that can be used in several types of olefin metathesis transformations with a wide range of substrates. Studying the effects of the building blocks on the catalysts will give us fundamental knowledge to further enhance their performance through structure-activity relationships. In addition to research done in conventional synthetic laboratories, new advances in computational chemistry will be incorporated in the research program to gain further insight into the catalysis. The development of catalyst systems with excellent thermal stability, activity, and substrate scope will greatly benefit from this multi-prong approach. The chemical structure of these new systems will be further tailored at a later stage (5 to 10-year timeframe) to address other complex issues, including that of selectivity. In the long term, this research program will lead to easy and controlled ways to make carbon-carbon double bonds, giving access to materials and organic compounds with new and enhanced properties, including drugs with potent biological activity.