Radical deaminative ipso-cyclization of 4-methoxyanilines with 1,7-enynes for accessing spirocyclohexadienone-containing cyclopenta[c]quinolin-4-ones

Jie Li, Wen-Wen Zhang, Xiao-Jing Wei, Feng Liu, Wen-Juan Hao, Shu-Liang Wang,* Guigen Li, Shu-Jiang Tu,* Bo Jiang*

A new C-center radical-triggered bicyclization cascade of N-tethered 1,7-enynes for forming 28 examples of biologically interesting spirocyclohexadienone-containing cyclopenta[c]quinolin-4-oneswith two all-carbon quaternary stereocenters has been established under mild conditions.The in situ generated diazonium salts from 4-methoxyanilines and t-BuONO are served as 4-methoxyphenyl precursors without additional oxidant, enabling 6-exo-dig cyclization/5-exo-trig ipso-cyclization to construct three new C-C bonds through metal-free dearomatization. The reaction also features broad substrate scope, annulation efficiency and high functional group tolerance.

J. Org. Chem. 2017, 82, 6621-6628