New Methods for Nitrogen and Oxygen Heterocycle Synthesis

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Project Summary/Abstract The efficient production of small organic molecules and chemical processes impacts pharmaceutical research, both drug discovery and process chemistry. Chiral compounds make up a substantial portion of bioactive small organic molecules. Their enantioselective synthesis minimizes use of chiral separation technology, which can be time and resource intensive, and the production of undesired enantiomers, which are often considered chemical waste. New copper-catalyzed alkene difunctionalization reactions that enable efficient and stereoselective synthesis of chiral amine derivatives and ethers, including saturated heterocycles, are being developed. The products of these reactions readily map on to structures contained in bioactive organic small molecules such as natural products and pharmaceuticals. In Aim 1, enantioselective aerobic copper-catalyzed alkene oxidative difunctionalizations will be explored for the direct synthesis of 2-formyl pyrrolidines and 2-formyl tetrahydrofurans. Application of these aerobic cyclizations to the streamlined synthesis of bioactive natural products and small molecule intermediates useful to drug discovery will test the practical utility of the methods. The focus of Aim 2 is the development of methods for the enantioselective synthesis of chiral bridged bicyclic ketals and other saturated heterocycles that contain fully substituted carbon stereocenters. A number of these transformations are enabled by a radical group transfer strategy. Mechanistic aspects of these reactions will be explored, which will enable their rational optimization and predictable application. The focus of Aim 3 is on the development of copper-catalyzed 2- and 3-component reactions that involve the coupling of alcohol and amine derivatives with styrenes or dienes, and alkyl radicals formed in situ. Mechanistic aspects of these reactions, especially related to stereoselectivity, will be investigated. Development of these chemical transformations will enable their use in multi-step organic synthesis in drug discovery and chemical biology applications. Their invention enables new options for synthetic organic chemists, which may enable diverse small molecule candidates to be synthesized efficiently. Lessons learned in reaction engineering for efficiency and selectivity will be applicable to the invention and development of related useful chemical processes.