Photocatalytic One-Step Synthesis of Unsymmetrical Azines
Yiping Wang, Zhenzhen Guo, Jian‐Ping Qu, Yan‐Biao Kang
Abstract
Unsymmetrical azines are useful functional materials. The synthesis of unsymmetrical azines via iminyl radical N–N bond cross-coupling is dramatically challenging compared with the N–N homocoupling. The balance of two different iminyl radical intermediates is crucial. The control of the selectivity of N–N coupling over the N-abstraction of a hydrogen atom is also vital. A dual functional photocatalyst is the key to access the synergistic energy transfer (EnT)-single-electron transfer (SET) relay (EnT triggered SET) which can work both as an EnT PC and as a SET PC. In this work, by the strategy of synergistic EnT-SET relay catalyzed by the single dual functional organophotocatalyst CBZ6, the cross coupling of two different amyl iminyl radicals for the synthesis of unsymmetrical azines has been achieved. A twisted carbazole-cored highly electron-rich heterocycle CBZ6 plays dual roles as an EnT and SET organophotocatalyst.