Photochemical and Photocatalytic Amination Reactions with Monovalent Nitrogen-based Reactive Intermediates

点击翻译按钮获取中文摘要

The amination represents one of the most important reactions in organic synthesis and is widely used in drug discovery or material sciences. Typically, aminations are realized via classic substitution reactions or via metal-catalyzed coupling reactions. An alternative lies within amination reactions using nitrene intermediates. However, such amination reactions are even today severely limited and often require forcing reaction conditions, since basic amines can easily inhibit the Lewis acidic transition metal catalysts. Under photochemical or photocatalytic conditions however, a free nitrene or a free nitrene radical anion can be generated, thereby overcoming classic limitations of nitrene transfer reactions. So far such photochemical or photocatalytic nitrene transfer reactions have only been used sporadically in organic synthesis, and current work is mainly limited to the use of high-energy UV light. The use of visible light has only been described in a few selected cases. Building on our work on photochemical and photocatalytic nitrene transfer reactions, we now want to examine these in detail here. The understanding of reactivity and identification of suitable new reagents plays a central role in enabling such nitrene transfer reactions and is therefore an important task in the development of sustainable synthetic methods and in understanding this conceptual approach in organic synthesis. In a first part, the planned work focuses on photochemical and photocatalytic amination reactions of poly-unsaturated hydrocarbons as well as C-H amination reactions with iodinanes to gain an understanding of the reactivity of free nitrenes. Further work focuses on expanding the range of applications with regard to the aminating reagent. Different amination reagents will be systematically investigated and applied in amination reactions. All planned studies include detailed mechanistic experiments, such as absorption spectroscopy, fluorescence quenching, or cyclic voltammetry, as well as DFT calculations to support the experimental data and elucidate reaction mechanisms.