Studies On Copper-catalyzed Oxidative Coupling Of Indoles To Construct N-heterocyclic Compounds

Indole derivatives are privileged structures in agrochemicals,pharmaceuticals and nature products.The indole ring constitutes a key structural feature in many alkaloid natural products and important compounds with pharmaceutical and biological activities.In recent years,direct functionalization of the indole ring has been attracted much attention.Consequently,great efforts have been devoted to establish towards the synthesis of these important molecular features catalyzed by transition-metal.In this paper,we have developed an efficient route for the construction of C-N bond and polycyclic aromatic compounds.Firstly,we have developed a green and efficient oxidative C-H/N-H coupling between indole and phenothiazine derivatives.Then,a concise route for the construction of polycyclic aromatic compounds has been achieved by Cu-catalyzed oxidative coupling.The reaction not only utilizes green oxidant but also avoids the harsh conditions.This paper mainly includes the following two parts:1:Copper-catalyzed aerobic oxidative amination of indole derivatives via single-electron transferWe have developed a green and efficient oxidative C-H/N-H coupling between indole and phenothiazine derivatives.This approach can be performed by Cu(I)/air system under the mild conditions.A series of indole derivatives and phenothiazines were compatible with the optimized condition to deliver the amination products in good to excellent yields.Mechanistically,both indole and phenothiazine derivatives were applied to be oxidized by copper(II)via single-electron-transfer,which followed by the cross coupling to furnish the transformation.At the same time,this approach opens up new perspectives in the application of phenothiazine as nitrogen group sources for C-N bond formation reactions.2:Copper-catalyzed oxidative coupling of indoles on the construction of polycyclic aromatic compoundsWe have disclosed a novel catalytic system to prepare the polycyclic aromatic compounds from dimer-indoles catalyzed by Cu(II).This reaction utilizes the interaction of Cu(OAc)₂ with the 3-position of dimer-indole to achieve the insertion of metal,followed by oxidative coupling reaction to generate the desired product.A wide range of substrates are compatible with this transformation.This strategy can be performed by Cu(II)/Na₂S₂O₈ system under the mild conditions.