Chemoselective Trimerization of Isocyanides: De Novo Synthesis of 2-Indole-Substituted Quinolines and Pyridines.

A catalyst-free chemoselective trimerization reaction of readily available isocyanides is described. This domino reaction provides facile access to a wide range of 2-(indol-2-yl)-quinolines and 2-(indol-2-yl)-pyridines in moderate to excellent yields. A "head to head" heterodimerization of two isocyanides is proposed as the key step of this reaction.