The Amination/Alkoxylation Of Nitrogen Heterocycles Through Organic Photosynthesis And Electrosynthesis

The C–N bond formation and C–O bond formation are two basic reactions in organic chemistry,and these two chemical bonds are widely present in drug molecules,natural products,and functional materials.The cross-dehydro-coupling（CDC）reaction refers to the cross-coupling reaction in which the C–H bond of two different reaction substrates forms a carbon-heterobond.The CDC reaction has the advantages of high efficiency,atomic economy and environmental friendliness,and conforms to the concept of green synthesis.Therefore,from the perspective of organic synthesis methodology,the CDC reaction is one of the simplest and most effective methods to construct carbon-heterobond.Organic photosynthesis and organic electrosynthesis,as two emerging organic synthesis techniques,have attracted special attention in recent years and have been widely used in fields such as C–H bond activation.Based on the above research background,we combined the advantages of organic photosynthesis and organic electrosynthesis to further expand the CDC reaction,and made the following specific research:1.Using quinoxaline-2（1H）-ones and azole compounds as the substrates and the reaction was run in CH₃CN under LED（390–395 nm,1.5 W）irradiation in air at room temperature without addition of photocatalyst,the C3-amination of quinoxaline-2（1H）-ones proceeded selectively.The reaction substrate has good generality,and the C3-position amination of quinoxaline-2（1H）-ones can be obtained in good yield under an air atmosphere at room temperature.2.2H-Indazoles reacted with azole compounds in an undivided cell equipped with a carbon anode and a Pt cathode using CH₃CN as a solvent,and ⁿBu₄NBF₄ as a mediator and electrolyte under constant current（5 m A）conditions for 3 h.And the C3-position amination of 2H-indazoles can be obtained.The reaction used cheap and commercially available azole compounds and chain aliphatic amines as amine sources,and can proceed smoothly under room temperature conditions, and has some advantages such as wide substrate application range,high yield, greenness,economy and so on.3.2H-Indazoles and alcohols were chosen as the substrates and when the reaction was carried out in the presence of Mes-Acr⁺Cl O₄^-as photocatalyst and Selectfluor as oxidant under N₂ atmosphere and 1.5 W blue LED（450–455 nm）irradiation,a C3-ethoxylation of 2H-indazole product,3-ethoxy-2H-indazoles were obtained; When the reaction was performed in the presence of Mes-Acr⁺Cl O₄^-as photocatalyst without Selectfluor under O₂ atmosphere and 1.5 W blue LED （450–455 nm）irradiation,a ring-opening of 2H-indazole product,2-ester azo compounds were isolated.A high chemoselectivity of visible-light-induced reaction of 2H-indazoles with alcohols controlled by the reaction atmosphere（N₂ or O₂）was developed.