Dual-Functionalization of Alkynes via Copper-Catalyzed Carbene/Alkyne Metathesis: A Direct Access to the 4-Carboxyl Quinolines

A copper-catalyzed novel carbene/alkyne metathesis cascade reaction with alkyne-tethered diazo compounds is described. The whole transformation features a dual-functionalization of alkyne to install one C═N and one C═C bond on each carbon with azide and diazo groups, respectively, in one reaction, which represents a practical synthetic alternative to the multisubstituted 4-carboxyl quinoline derivatives and with most of them in high to excellent yields.