Reagent-Free C-H/N-H Cross-Coupling: Regioselective Synthesis of N-Heteroaromatics from Biaryl Aldehydes and NH3

An unprecedented synthesis of N-heteroaromatics from biaryl aldehydes and NH3 through reagent-free C-H/N-H cross-coupling has been developed. The electrosynthesis uses NH3 as an inexpensive and atom-economic nitrogen donor, requires no oxidizing agents, and allows efficient and regioselective access to a wide range of phenanthridines and structurally related polycyclic N-heteroaromatic products.