Selective Synthesis of N-H and N-Aryl Benzotriazoles by the [3 + 2] Annulation of Sodium Azide with Arynes.

The synthetic utility of NaN3 as the azide component in the [3 + 2] annulation with arynes generated from 2-(trimethylsilyl)aryltriflates resulting in the transition-metal-free synthesis of N-H and N-aryl benzotriazoles has been demonstrated. Using CsF as the fluoride source in CH3CN, the N-H benzotriazoles are formed in high selectivity instead of the expected azidobenzene. Interestingly, N-aryl benzotriazoles are formed using KF and THF as solvent in an open-flask reaction. Moreover, a method for the N1-arylation of benzotriazole is also presented.