Pd-Catalyzed Allylic Oxidation Reactions

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The oxidation of organic chemicals to make specific target chemicals using oxygen, a green oxidant, remains a significant challenge for the chemical industry. Dr. Shannon Stahl of the University of Wisconsin-Madison is developing catalysts that enable oxygen to be used as an oxidant in selective conversions of simple feedstock chemicals into pharmaceuticals. The oxidation of C-H bonds is of particular interest to the pharmaceutical industry because it enables drug molecules to be prepared efficiently or modified to optimize their properties. Organic molecules have a large number of different C-H bonds, and the reactions being developed by Dr. Stahl are designed to oxidize only specific C-H bonds in those molecules. This selectivity is accomplished by catalyst design, combined with novel experimental techniques in collaboration with scientists at Merck Research Laboratories. This university-industry collaboration is leveraged to enhance the broader impact of the research. Students participating in on-site research visits at Merck are working with Dr. Stahl and campus safety representatives at UW-Madison to help implement new industry-based safety protocols within the University research environment. Human resource development efforts target enhanced diversity in the graduate student population by leveraging multiple programs in place at UW-Madison.With funding from the Chemical Catalysis Program of the Chemistry Division, Dr. Shannon Stahl of the University of Wisconsin at Madison is developing new allylic C-H oxidation reactions that are compatible with the use of O2 as the stoichiometric oxidant. The targeted reactions proceed with unprecedented catalyst-controlled chemo-, regio- and stereoselectivity, enabled by the discovery, design and development of new ancillary ligands for the Pd catalyst. The catalyst and reaction development efforts are closely coupled to rigorous mechanistic studies that implement innovative mechanistic tools such as a high-pressure NMR reactor capable of on-line continuous delivery of O2 at pressure and operando X-ray absorption spectroscopy. A strategic collaboration with scientists at Merck Research Laboratories provides access to high-throughput experimentation and analysis to discover catalytic allylic oxidation reactions that enable selective late-stage functionalization of natural products or existing pharmaceuticals. Students participating in on-site research visits at Merck are working with Dr. Stahl and campus safety representatives at UW-Madison to help implement new safety protocols they encounter during their time at Merck. In addition, these students are working with Dr. Stahl to develop a reaction screening and optimization statistical analysis module for implementation in the graduate curriculum at UW-Madison.