Tosylazide as N1-Synthon: Iron-Catalyzed Nitrogenative Dimerization of Indoles to p-Bisindolopyrazine Derivatives

We present a straightforward one-step process to access a range of novel p-diindolepyrazines via an unprecedented [n-Bu4N][Fe(CO)(3)(NO)] (TBA[Fe])-catalyzed intermolecular nitrogenative dimerization of various indole derivatives. Remarkably, tosylazide functions as a N1-synthon forming the central pyrazine unit that joins the two indole subunits. The catalytic transformation shows a good substrate scope, and the obtained products show interesting electronic properties.