Oxidation of organics catalyzed by earth--abundant transition metal ions

通过对化学原料进行高效、选择性和环境友好的改性来创造增值化学品仍然是一项迫切的挑战，需要新型催化剂。一组特别重要的反应是有机化合物氧化成含氧和含氮分子。由于碳氧（C-O）和碳氮（C-N）键在平台化学品、药物和天然产物中普遍存在，将O和N基团引入有机支架是有机合成中的一个重要课题。在这个项目中，我们设计了新的氧化过程来产生这种具有催化和选择性的键。我们还致力于使用无污染的氧化剂，如空气或过氧化氢，以及地球上丰富的低毒性金属，如铜和铁。提出的研究目标有三个：目标1：开发利用N-O键作为活化剂的催化氧化。这个目标将集中于设计金属催化剂，其中N-O键促进了衬底上的关键氧化步骤。我们将重点关注醇氧化，以及在酚和烯烃上添加氮基团，以创建含氮的分子构建块。-目的2：了解C-C和C-O偶联反应对金属自由基配合物的选择性。这类反应与氧化金属酶有关，在合成策略中很重要（例如，聚苯醚的合成规模达数百万吨，交叉脱氢偶联反应对精细化学合成至关重要）。-目标3：在酚类及其衍生物上发展绿色、催化的C-C和C-O键形成反应。溶剂的使用一直被强调为精细化学工业的一个主要陷阱，因为处理溶液会产生废物。因此，我们希望应用无溶剂方法来开发氧化苯酚化学的绿色工艺。目标是创造在实际条件下将苯酚转化为增值化学品的新方法。这个程序的共同主题是使用氧化还原活性配体，即具有自身氧化还原性质的配体，包括自由基。该方案的创新之处在于在金属基氧化催化的背景下系统地使用这些配体。我们非常重视酚类，因为该行业缺乏有效和有选择地将其转化为有用的构建模块的方法。这项工作的长期成果将是使用来自生物质木质素部分的酚，因为它代表了可再生生产社会所依赖的增值芳香族化合物的唯一可行来源。这个综合项目结合了我的专业知识中的配位化学和有机方法论，并为各种背景的高素质人才提供多学科和协作培训。

Creating value-added chemicals by efficient, selective and environmentally friendly modifications of chemical feedstock remains an urgent challenge that requires new types of catalysts. A particularly important group of reactions are oxidations of organic compounds into oxygen and nitrogen-containing molecules. Owing to the prevalence of carbon-oxygen (C-O) and carbon-nitrogen (C-N) bonds in platform chemicals, pharmaceuticals and natural products, the introduction of O and N groups into organic scaffolds is an important topic in organic synthesis. In this program, we design novel oxidative processes for the creation of such bonds that are catalytic and selective. We also aim to use wasteless oxidants such as air or hydrogen peroxide and earth-abundant, low-toxicity metals such as copper and iron. The proposed research targets three objectives: - Objective 1: To develop catalytic oxidations using the N-O bond as an activator. This objective will focus on designing metal catalysts where an N-O bond facilitates the key oxidation step on the substrate. We will focus on alcohol oxidations, as well as additions of nitrogen groups to phenols and alkenes to create nitrogen-containing molecular building blocks. - Objective 2: To understand the selectivity of C-C and C-O coupling reactions on metal-radical complexes. Such reactions pertain to oxidative metallo-enzymes and are important in synthetic strategies (for example, polyphenylene ethers are synthesized at a multi-million ton scale and cross dehydrogenative coupling reactions are essential for fine chemical synthesis). - Objective 3: To develop green, catalytic C-C and C-O bond formation reactions on phenols and their derivatives. The use of solvents has consistently been highlighted as a major pitfall of the fine chemical industry because of the waste generated by processing solutions. We thus wish to apply solvent-free methods to develop green processes in oxidative phenol chemistry. The goal is to create new methodologies for the conversion of phenols into value-added chemicals under practical conditions. The common theme of this program is the use of redox-active ligands, i.e. ligands that possess their own redox properties, including radicals. The innovation of this program lies in the systematic use of these ligands in the context of metal-based oxidation catalysis. We place a strong emphasis on phenols because the industry lacks methods to convert them efficiently and selectively into useful building blocks. The long-term outcome of this work will be to use phenols derived from the lignin fraction of biomass because it represents the only viable source to renewably produce value-added aromatic compounds on which society depends. This comprehensive program combines coordination chemistry and organic methodology within my expertise and provides multi-disciplinary and collaborative training for highly qualified personnel of all backgrounds.