Novel oxidative functionalizations using earth-abundant transition metals

选择性有氧氧化的发展对化学工业至关重要，因为分子氧丰富，并且通过将其还原为水提供可持续的能源。一组特别重要的氧化反应是将氧或氮原子直接一步转移到失活的有机底物上，从而产生通常用作燃料、溶剂和润滑剂的分子，或用作精细化学品和药品合成中的基本构件。此外，这些直接的原子转移避免了浪费的保护群策略的中间作用。然而，目前大多数方法使用有毒金属离子或浪费氧化剂，这是不希望大规模应用。******本研究计划的任务是在环境友好的条件下，利用地球上丰富的金属离子，开发氧气或氮转移到基质的新策略。这项研究将遵循两个主要重点。(1)：从生物含金属酶中获得灵感，这些酶在将空气中的氧气转移到底物中是高效和选择性的。(2)：开发原子经济的新型氧氮转移试剂和催化剂，并使用地球上储量丰富的无毒金属离子，如铁和铜。我们提出了四个研究目标：******-目标1：制备模拟酶的分子，研究它们的结构和反应性，以开发更有效和更有选择性的催化剂。我们将特别关注与环境中芳烃降解有关的反应。******-目标2：制备金属自由基加合物模型并研究其与自由基伙伴的偶联反应。这些反应与生物学有关，在合成策略中也很重要（例如，数百万吨规模的聚苯醚制造或交叉脱氢偶联）。******-目标3：采用含有氮氧键的受限氧化还原活性配体来促进氧转移。******-目标4：开发一种将含氮基团转移到酚上的新方法，并打开一步获得氨基酚构建块的途径。******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。虽然与这些配体的金属配合物的结构是很清楚的，但文献很少报道它们的反应性。我们项目的新颖之处在于在氧化反应的背景下系统地使用这些配体，特别是在酚类上，目前工业上没有充分利用这些配体，因为没有好的方法将它们有效地、有选择地转化为有用的材料。因此，这项工作的预期结果将是理解和开发新的氧化方法，这将使该行业将未使用的化学品视为新的原料。

The development of selective aerobic oxidations is fundamentally important to the chemical industry due to the abundance of molecular oxygen and the sustainable source of energy provided by its reduction to water. A particularly important group of oxidation reactions is the direct, one-step transfer of an oxygen or nitrogen atom to an inactivated organic substrate, which generates molecules that are typically used as fuels, solvents and lubricants or as building blocks in the synthesis of fine chemicals and pharmaceuticals. Also, these direct atom transfers avoid the intermediacy of wasteful protecting-group strategies. However, most current methods employ toxic metal ions or wasteful oxidants, which is undesired for scaled-up applications.******The mission of this research program is to develop new strategies for oxygen or nitrogen transfer to substrates using earth-abundant metal ions under conditions that are environmentally benign. This research will follow two main thrusts. (1): get inspiration from biological metal-containing enzymes that are efficient and selective at transferring oxygen from the air into substrates. (2): develop novel reagents and catalysts for oxygen and nitrogen transfers that are atom-economical and employ earth-abundant and non toxic metal ions such as iron and copper. We propose four research objectives:******- Objective 1: to prepare molecules that mimic the enzymes and study their structure and reactivity to develop more efficient and more selective catalysts. We will particularly focus on reactions that are involved in the degradation of aromatics in the environment.******- Objective 2: to prepare models of metal-radical adducts and study their coupling reactions with radical partners. Such reactions pertain to biology and are also important in synthetic strategies (for example the fabrication of polyphenylene ether at a multi-million ton scale or cross dehydrogenative couplings).******- Objective 3: to employ constrained redox-active ligands containing an nitrogen-oxygen bond to facilitate oxygen transfer. ******- Objective 4: to develop a new methodology to transfer nitrogen-containing groups on phenols and open a one-step access to aminophenol building blocks.******The common theme of this program is the use of redox-active ligands, i.e. ligands that possess their own redox properties. Although the structure of metal complexes with these ligands is well understood, the literature is scarce with reports of their reactivity. The novelty of our program stands in a systematic use of these ligands in the context of oxidation reactions, especially on phenols, which are currently underused by the industry because there is no good method to convert them efficiently and selectively to useful materials. Thus, the expected outcome of this work will be the understanding and development of new oxidative methods that will allow the industry to think of unused chemicals as new feedstock.