One-Pot Preparation of 9,10-Dihydrophenanthrenes Initiated by Rhodium(III)-Catalyzed C–H Activation and Relay Diels–Alder Reaction
Dingding Gao, Xingyu Liu, Hao Xu, Yun‐Xuan Tan, Qi Liao, Qinghua Li, Xiaodi Yang, Guo‐Qiang Lin, Ping Tian
Abstract
An efficient one-pot synthesis of multisubstituted 9,10-dihydrophenanthrenes from easily available 2-arylazaarenes and cyclohexadienone-tethered terminal alkynes (1,6-enynes) has been successfully achieved. This domino reaction proceeded smoothly through Cp*Rh(III)-catalyzed C-H activation, direct protonation of alkenyl-Rh intermediates, intramolecular Diels-Alder reaction, alkene isomerization, subsequent ring-opening aromatization, and acetylation. This strategy was pot-economical and tolerated a wide range of functional groups. Moreover, the potent anticancer activities against HepG2 cells were observed for these artificial 9,10-dihydrophenanthrene derivatives.