Multiple Metal-Carbon Bonds, Metallacycles and Catalytic Olefin Metathesis Reactions

该奖项由化学系化学催化计划资助麻省理工学院理查德·R·施罗克教授开展基于钼和钨这两种富含稀土元素的烯烃歧化催化剂的基础研究。烯烃歧化反应是有机分子中碳-碳双键断裂和重排的反应。烯烃歧化反应使与治疗癌症和艾滋病等疾病的天然和非天然产物相关的有机分子的合成以及特种材料的合成发生了革命性的变化。施罗克教授正在研究使催化剂比以往任何催化剂更具活性、选择性和耐用性的方法。这项研究的更广泛的影响可能是在进一步推动烯烃复分解在化学科学中的作用，促进烯烃复分解的商业应用，以及培训和教育学生方面。施罗克研究小组正在对新设计的烯烃复分解反应催化剂进行合成、机理、结构和反应活性研究。目前正在研究四个新的催化剂类别，重点关注烯烃歧化催化中的几个具体挑战：合成通过Lewis酸与氧代配体结合而活化的新的钨的氧代亚烷基配合物；在二氧化硅上负载定义明确的氧代亚烷基歧化催化剂；开发含有空间要求高的2，6-二取代苯亚胺配体的亚胺基亚烷基催化剂，以将反应限制在仅能形成反烷基亚甲基异构体的反应；以及创建潜在活性更高的、配位不饱和的阳离子与弱配位阴离子配对。多相复分解催化剂被用于体积最大的复分解反应，但对于如何将它们制备成单一的、定义明确的表面物种并在分子水平上控制其反应活性，人们知之甚少。这项研究有可能产生新的复分解催化剂，并促进对复分解化学的总体理解。

With this award, the Chemical Catalysis Program of the Division of Chemistry is funding Professor Richard R. Schrock of the Massachusetts Institute of Technology to carry out fundamental studies on olefin metathesis catalysts based on the two earth abundant elements, molybdenum and tungsten. Olefin metathesis is a reaction that consists of breaking and rearranging carbon-carbon double bonds in organic molecules. The olefin metathesis reaction has revolutionized the synthesis of organic molecules relevant to natural and unnatural products for treatment of diseases such as cancers and AIDS, as well as the synthesis of specialty materials. Professor Schrock is studying ways to make the catalysts more reactive, selective, and durable than any previous catalysts. The broader impacts of the research could be wide ranging in terms of furthering the role of olefin metathesis in chemical science, advancing commercial uses of olefin metathesis, and training and educating students.The Schrock research group is performing synthetic, mechanistic, structural, and reactivity studies of newly designed catalysts for the olefin metathesis reaction. Four new catalyst classes are being investigated with a focus on several specific challenges in olefin metathesis catalysis: synthesizing new oxo alkylidene complexes of tungsten that are activated through binding of a Lewis acid to the oxo ligand; supporting well-defined oxo alkylidene metathesis catalysts on silica; developing imido alkylidene catalysts that contain a sterically demanding 2,6-disubstituted phenylimido ligands in order to limit reactions to ones in which only anti-alkylidene isomers can form; and creating potentially more reactive, coordinatively unsaturated cationic complexes paired with a weakly coordinating anion. Heterogeneous metathesis catalysts are employed for the largest volume metathesis reactions, but the least is known about how to prepare them as single, well-defined species on the surface and to control their reactivity at a molecular level. This research has the potential to generate new classes of metathesis catalysts and advance the general understanding of metathesis chemistry.