Green Chemistry using Early Transition Metal Catalysts for the Synthesis of Small Molecules and Materials

含氮化学品，胺，是生物组装的关键组分，如蛋白质和DNA，以及合成产品，如药物，农用化学品和响应材料。含胺材料是高价值产品，具有从CO2捕集材料到抗微生物涂层的多种应用。由于胺在有用的商业产品中的普遍存在，化学家已经开发了许多方法来选择性地将氮安装到化合物中，其中许多产生大量的废物。我的计划旨在为化学工业开发可持续技术，使含胺分子和材料。多年来，Schafer集团通过开发用于胺的选择性、原子经济性合成的催化剂，推进了绿色化学。此外，本研究计划的特点是使用3d前过渡金属钛和钒，这些金属资源丰富，成本低，毒性低。 我们对这些催化剂的理解启发了对醇而不是胺的研究。醇可以从生物质来源中可再生地获得，并且是将化学制造转变为循环经济的关键组成部分。我们的研究计划开创了一类催化剂的发展，其特征是N，O-螯合配体作为改变催化活性的关键组分。N，O-螯合框架很容易被修饰，使得快速识别改进的甚至新的转化变得简单。本科生，研究生和博士后水平的学员完成详细的结构，动力学和计算力学实验，以了解这些转换是如何发生的。这些见解指导了增强的催化剂开发工作，并产生了世界领先的炔与胺的加氢官能化反应和广泛适用于通过加氢氨基烷基化直接催化胺化烯烃的催化剂。在过去的六年中，我们已经表明，尿素氮，O-螯合络合物的钽促进这一反应与广泛的胺和烯烃，我们已经学会了如何控制区域和非对映选择性的这些转换。在这里，我们建议将这些催化剂的钛变体应用于制备天然产物和药物分子中普遍存在的氨基酸和各种N-杂环化合物的替代成键策略中。我们还建议与学术和工业合作伙伴合作，制备新的胺官能化聚合物，用于防腐蚀涂料，抗微生物添加剂和CO2捕获材料。我们还寻求开发催化剂，通过在改进的McMurry偶联中使用醇偶联反应，可以产生我们用于加氢官能化反应所需的烯烃起始材料。因此，该提案旨在推动使用生物质衍生的可再生资源来合成高价值的小分子胺和材料。

Nitrogen containing chemicals, amines, are key components of biological assemblies, like proteins and DNA, as well as synthetic products such as pharmaceuticals, agrochemicals and responsive materials. Amine containing materials are high-value products that have diverse applications ranging from CO2 capture materials to anti-microbial coatings. Due to the prevalence of amines in useful commercial products, chemists have developed many ways to selectively install nitrogen into compounds, many of which generate significant waste. My program aims to develop sustainable technologies for chemical industries that make amine containing molecules and materials. Over the years the Schafer group has advanced green chemistry by developing catalysts for the selective, atom-economic synthesis of amines. Also, this research program features the use of 3d early transition metals, titanium and vanadium, which are abundant, of low cost and low toxicity.  Our understanding of these catalysts have inspired investigations with alcohols, rather than amines. Alcohols can be renewably obtained from biomass sources and are key building blocks for transitioning chemical manufacturing into the circular economy. Our research program has pioneered the development of a class of catalysts that feature N,O-chelating ligands as key components to modify catalytic activity. The N,O-chelating framework is easily modified, making it simple to rapidly identify improved or even new transformations. Trainees at the undergraduate, graduate and postdoctoral levels complete detailed structural, kinetic and computational mechanistic experiments to understand how these transformations occur. These insights guide enhanced catalyst development efforts and have resulted in world-leading hydrofunctionalization reactions of alkynes with amines and broadly useful catalysts for the direct, catalytic amination of alkenes by hydroaminoalkylation. Over the past six years we have shown that ureate N,O-chelated complexes of tantalum promote this reaction with a broad range of amines and alkenes and we have learned how to control both the regio- and diastereoselectivity of these transformations. Here we propose to apply titanium variants of these catalysts in alternative bond-making strategies for preparing amino acids and a variety of N-heterocycles that are prevalent in natural products and drug molecules. We also propose to prepare new amine functionalized polymers that will be investigated, in collaboration with academic and industrial partners, for use as anti-corrosion coatings, anti-microbial additives, and CO2 capture materials. We also seek to develop catalysts that can generate the alkene starting materials that we need for hydrofunctionalization reactions, by using alcohol coupling reactions in a modified McMurry coupling. Thus, this proposal aims to push toward using biomass derived, renewable resources for the synthesis of high-value small molecule amines and materials.