Amine-Catalyzed Direct Photoarylation Of Unactivated Arenes

Biaryls are one of the most important classes of organic compounds that are frequently found in natural products, pharmaceutically active reagents, agrochemicals, dyes, etc., and have attracted much interest in advanced materials and supramolecular sciences. Thus, the development of efficient protocol to synthesize biaryls is highly desired and of great importance for organic synthesis. Research in this field is an important part of synthetic methodology.My research is mainly focused on the amine-catalyzed biaryl reaction under UV irradiation at room temperature, which presents a new method to produce biaryls.My research includes the following sections,Part Ⅰ:After extensively reviewed the literatures, the main idea and detail experimental program were proposed.Part Ⅱ:The optimization of the amine-catalyzed direct photoarylation of unasetivated arenes reaction under the UV irradiation was carried out carefully. The different wavelengths, solvent effect, different kinds and amount of catalysts, and a series of controlled trials were examined step by step, after which the optimized reaction conditions were finalized.Part Ⅲ:The substrates scope with a series of alkynes was studied. Electron, steric, and substituent effect were examined. And the law was summed up.Part Ⅳ:The possible mechanism was discussed based on the results.A new synthetic method of biaryls derivatives was developed during this research, which reaction proceeds through a new type of amine-catalyzed single electron transfer initiated radical coupling procedure to form biaryls in high yields under UV irradiation at room temperature. Although a lot of efficient synthetic methods have been developed in synthesis biaryls, most of which need additional additives such as toxic transition metal catalysts, strong bases, or large amounts of other organic additives. This greener protocol provides a new strategy to achieve direct aromatic C-H functionalization and offers a new example of cost-effective and environmentally benign access to biaryls.