but efficient: Aza‐fused polycyclic quinolines were efficiently assembled throughrhodium(III)‐based direct double CHactivation of N‐aryl azoles followed by cyclization with alkynes without heteroatom‐assisted chelation. Copper(II) acetate, aside from acting as an oxidant, could also play an important role in the CHactivation process.
The rhodium-catalyzed dehydrogenative coupling of N-pyridylindoles with alkynes proceeds smoothly through rollover cyclometalation to produce indolo[1,2-a][1,8]naphthyridine derivatives. A number of tetra-, penta-, and hexacyclic N-containing heteroaromatics can also be readily constructed in a similar manner. The L-shaped pi-conjugated molecules exhibit intense solid-state fluorescence.