Straightforward Access to Novel Indolo[2,3-b]indoles viaAerobic Copper-Catalyzed [3 + 2] Annulation of Diarylamines and Indoles

Taoyuan Liang,^aLingzhen Gong,^a He Zhao,^a Huanfeng Jiang^aandMin Zhang*^,a

ABSTRACT:Herein, we report an unprecedented aerobic copper-catalyzed [3 + 2] annulation reaction of diarylamines with indoles, which allows direct access to novel2-diarylaminoindolo[2,3-b]indoles, a class of potential photoelectric device molecules. The developed transformation proceeds with broad substrate scope, good functional group tolerance,high chemo-selectivity, and no need for pre-preparation of specific agents, which offers a practical way for diverse and atom-economic synthesis ofthedesiredproducts that are difficult to prepare with the conventional approaches.