Cu-Enabled [3 + 2] Annulation of Formed Nitrile Ylides with Aryldiazonium Salts: Access to 5-Cyano-1,2,4-Triazoles.

The unified construction of cyano-substituted 1,2,4-triazoles, particularly the 5-cyano counterparts, remains underdeveloped. Herein we describe a three-component method to access a wide range of 1-aryl 5-cyano-1,2,4-triazoles using readily available 2-diazoacetonitriles, nitriles, and aryldiazonium salts. This regiospecific synthesis relies on the dipolar [3 + 2] annulation of the formed nitrile ylides with aryldiazonium salts.

Syntheses of Benzo[c]Chromen-6-ones by Palladium Catalyzed C-H Bond Activation using Diazonium Salts.

An efficient palladium catalyzed C-H bond activation for the synthesis of benzo[c]chromen-6-ones using diazonium salts is described. In the presence of Pd(OAc)2, dppp, PivOH and K2CO3, the diazonium salt can be transformed into the product through a denitrogenation/C-H bond activation/cyclization sequence in acetonitrile. Altogether, nine structurally diverse substituted benzoLc]chromen-6-ones were prepared in excellent yields through two different methods.