Study On Visible Light Induced Minisci Arylation

Nitrogen heterocyclic compounds are important skeleton structure which are widely applied in material science,agricultural chemistry,especially medicinal chemistry.There are many methods to functionalized nitrogenous heterocycles,especially the classical radical addition Minisci reaction that has been extensively studied.In recent years,visible light induced single electron transfer reactions have attracted wide attention,and have rapidly developed into a hot research field of organic synthetic chemistry.Though large number of scientists have made innovations and developments on the reaction methods of Minisci by visible light catalysis,their functional groups are mainly concentrated in alkylation,and the methods of visible light induced heterocyclic arylation are not common.A novel direct C-H arylation of nitrogen heterocyclic compounds has been developed using visible light induced strategy.With the strong oxidation and unstable properties,benzoyl peroxide takes part in the oxidation quenching cycle of the visible light catalyst as an oxidizing agent and divides itself into radical part and anion part;Decarboxylation of the radical part provides the aryl radical,and anion part will promote the HAT occurs in subsequent rearomatization process of protonated heterocyclic.Meanwhile,the catalyst on high valence is reduced to the initial state to complete the catalytic cycle and deliverd the target product.By using this method,31 products were obtained,and the yield was between 17%-58%.Then a reasonable mechanism was proposed to reveal the microscopic process of this reaction.In this paper,visible light catalysis method is used with mild and no heating conditions.The use of cheap and low toxic benzoyl peroxide as the oxidant and arylating reagent can successfully realize the aromatization of a variety of nitrogen heterocyclic compounds,avoiding the use of high toxic aromatic and excess oxygenating agents.All of these are in accordance with the concept of green chemistry and the principle of atomic economy.