New Catalysts for Cis-Selective Metathesis: Agostic Interaction and Meso-N-Heterocyclic Carbenes

本计画将合成新型烯烃复分解顺式选择性催化剂。 本项目将采用两种新的、尚未探索的方法：（1）利用早期过渡金属Fischer卡宾配合物中的agostic相互作用指导烯炔交叉复分解反应的选择性。 特别是，我们打算提高催化剂的稳定性的基础上，我们已经学到了以前在潜水员组，同时研究烯炔复分解。(2)在N-杂环卡宾设计的基础上，我们将在meso-N-杂环卡宾的一侧构建芳香“墙”以控制钌卡宾中的催化剂选择性。烯烃复分解反应是目前催化碳碳双键构筑的最有效方法之一，在许多领域得到了广泛的应用。尽管复分解化学取得了巨大的成功，但主要的限制是双键几何形状的控制：顺式双键不能选择性地形成。该项目的重点是通过催化剂的开发来解决顺式选择性问题。纽约布法罗州立大学化学系潜水员。 Steven Diver教授的研究工作集中在开发新的环合成复分解方法，研究烯炔复分解的催化机理和开发新的卡宾催化剂。 这三方面的努力影响了我们对金属卡宾反应性基本方面的理解，并导致某些合成应用中选择性的改善。 开发新的卡宾催化剂有望提高顺式选择性，并导致更好地了解哪些因素对选择性至关重要。复分解方法是高效的，使用少量的钌卡宾催化剂（称为Grubbs卡宾），并广泛适用于小分子（如药物）和聚合物结构（如纳米材料）的合成。新催化剂的成功开发将对制药部门的合成产生影响，从而提高药物生产的效率。

This project will synthesize new catalysts for cis-selectivity in olefin metathesis. Two new, unexplored approaches will be taken in this project: (1) Use of agostic interactions in early transition metal Fischer carbene complexes to guide selectivity in enyne cross metathesis. In particular, we intend to improve the catalyst stability building upon what we have learned previously in the Diver group while studying enyne metathesis. (2) Building on N-heterocyclic carbene design we will construct an aromatic 'wall' on one side of meso-N-heterocyclic carbenes to control catalyst selectivity in ruthenium carbenes. Currently, the olefin metathesis provides one of the most effective methods for catalytic carbon-carbon double bond construction, and has been widely used by chemists in many fields. Despite the huge success of metathesis chemistry, the major limitation is control of double bond geometry: cis-double bonds cannot be made selectively. This project is focused on this cis-selectivity problem through catalyst development.With this award, the Organic and Macromolecular Chemistry Program is supporting the research of Professor Steven T. Diver of the Department of Chemistry at the State University of New York-Buffalo. Professor Steven Diver's research efforts center on the development of new metathesis methods for the synthesis of rings, the study of the catalytic mechanism of enyne metathesis and the development of new carbene catalysts. This three-pronged effort has impacted our understanding of fundamental aspects of metal carbene reactivity and led to improvements in selectivity in certain synthetic applications. Development of new carbene catalysts is expected to enhance cis-selectivity and lead to a better understanding of which factors are critical to selectivity. Metathesis methods are highly efficient, using small amounts of ruthenium carbene catalysts (known as the Grubbs carbenes) and are widely applicable to the synthesis of small molecules (such as pharmaceuticals) and polymeric structures (such as nanomaterials). Successful development of new catalysts will have an impact on synthesis in the pharmaceutical sector, leading to improved efficiency in drug production.