A new palladium-catalyzed dearomatizative [2 + 2 + 1] carboannulation of 1,7-enynes with aryl diazonium salts and H2O is presented. The reaction enables the construction of spirocyclohexadienone-fused cyclopenta[c]quinolin-4(5H)-ones through a sequence of Heck-type addition, 6-exo-dig cyclization, ipso-cyclization, dearomatization and hydrolysis.
![Graphical abstract: Palladium-catalyzed dearomatizative [2 + 2 + 1] carboannulation of 1,7-enynes with aryl diazonium salts and H2O: facile synthesis of spirocyclohexadienone-fused cyclopenta[c]quinolin-4(5H)-ones](http://hg.y866.cn/compound/lib/scimg/usr/1/C7CC02830J.jpg)
