Rh(III)-Catalyzed Traceless Coupling of Quinoline N-Oxides with Internal Diarylalkynes

Quinoline N-oxides were found to undergo Cp*Rh(III)-catalyzed coupling with internal diarylalkynes to provide 8-functionalized quinolines through a cascade process that involves remote C-H bond activation, alkyne insertion, and intramolecular oxygen atom transfer. In this reaction, the N-oxide plays a dual role, acting as a traceless directing group as well as a source of oxygen atom, as confirmed by an O-18-labeling experiment.