Transition Metal-Radical Hybrid Methods for Organic Synthesis

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Project Description The proposed program aims at the development of a new synthetic platform for controlled selective functionalizations of aliphatic molecules possessing unreactive C(sp3)–H bonds. The existing synthetic methods toward complex molecules and pharmaceuticals mostly rely on employment of pre-functionalized substrates. Employment of non-functionalized saturated hydrocarbon groups is much more appealing as these moieties are much more abundant and cheap. Moreover, the aliphatic C(sp3)–H bonds are often present in complex biologically important molecules and pharmaceuticals, and thus their selective functionalization offers a powerful tool for late stage modifications. The few existing methods for functionalization of saturated groups are not general, as the functionalization site is usually substrate-controlled. Also, these methods operate under acidic conditions and/or employ external oxidants, which limits the substrate scope. Thus, mild regio- and stereo-controlled functionalization of saturated groups remains a holy grail in modern synthetic chemistry. We propose the development of a novel visible light-induced transition metal-radical hybrid catalytic methodology for regiocontrolled, mild, and external oxidant-free functionalizations of saturated groups. The site of functionalization will be controlled by a designed tool-kit of temporary auxiliaries, which potentially in one-pot fashion will be routinely installed onto substrate and removed from the product. The feasibility of a successful development of this project is supported by a vast amount of preliminary results obtained in our lab. The proposed project consists of three major Sections: 1. Development of efficient catalytic systems for functionalization of aliphatic groups. 2. Development of a tool-kit for general efficient and site-controlled proximal and remote functionalizations of various organic molecules. 3. Implementation of novel reactivity of transition metal-radical hybrid complexes under development toward new transformations including C(sp3)–H functionalizations and cascade reactions.