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

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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.