Mild Cu-Catalyzed Nitrogen–Iodine Exchange Strategy for the Synthesis of Non-Symmetric N,N′-Bicarbazole Scaffolds Using Cyclic Iodoniums

Copper/organic base-mediated dual N-arylation of N-amino carbazoles with cyclic diaryliodonium salts at room temperature has been unlocked, yielding nonsymmetric N,N′-bicarbazoles with a broad scope, especially tolerating all halogens (F, Cl, Br, and I). Besides, N-amino indole, pyrrole, piperidine, morpholine, and piperazines all proved to be suitable coupling partners. The bottom-up access from inorganic hydrazine and cyclic iodoniums through double N–I exchange is also presented. Some potential organic light-emitting diode materials are easily prepared, and the phenothiazine-tied bicarbazole scaffold shows the ability to detect 1,2-dichloroethane via UV irradiation.