Regioselective Cycloaddition Route to 5-Aminotriazoles

Significance

The regioselective synthesis of
5-aminotriazoles 3 from aryl azides 1 and cyano-acetyl pyrroles and indoles 2 is reported. The key to the regioselectivity is the presence of the electron-rich heteroaryl (R^²) group, which disfavors cyclization at the carbonyl position (path B), leading instead to attack on the nitrile (path A) giving rise to the observed products. Electron-donating, -neutral and -withdrawing aryl substituents are tolerated in the reaction and high yields were obtained for all examined cases.