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

凭借这一奖项，化学学部的化学催化项目资助了麻省理工学院的Richard R. Schrock教授开展基于两种地球丰富元素钼和钨的烯烃转化催化剂的基础研究。烯烃复分解是有机分子中碳-碳双键断裂并重新排列的反应。烯烃复分解反应彻底改变了与治疗癌症和艾滋病等疾病的天然和非天然产品相关的有机分子的合成，以及特种材料的合成。施罗克教授正在研究如何使催化剂比以往任何催化剂都更具活性、选择性和耐用性。这项研究的广泛影响可能是广泛的，在化学科学中进一步发挥烯烃转化的作用，推进烯烃转化的商业用途，以及培训和教育学生。Schrock研究小组正在对新设计的烯烃分解反应催化剂进行合成、机理、结构和反应性研究。目前正在研究四种新的催化剂类别，重点关注烯烃复分解催化中的几个具体挑战：合成新的氧烷基烯钨配合物，通过刘易斯酸与氧配体结合而激活；在二氧化硅上支持定义明确的氧基烷基二烯复分解催化剂；开发含有要求空间要求的2,6-二取代苯基氨基配体的亚胺烷基烯催化剂，以便将反应限制为只能形成反烷基烯异构体的反应；并产生潜在的更活泼的，配位不饱和的阳离子配合物与弱配位阴离子配对。多相复分解催化剂用于最大体积的复分解反应，但对于如何将其制备为单一的、明确定义的表面物种，以及如何在分子水平上控制其反应性，人们所知最少。这项研究有可能产生新的转化催化剂类别，并促进对转化化学的一般理解。

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.