Copper-Catalyzed Oxidative C(sp³)–H Functionalization for Facile Synthesis of 1,2,4-Triazoles and 1,3,5-Triazines from Amidines

A facile and versatile catalytic system involving copper catalyst, K₃PO₄ as the base, and O₂ as the oxidant has been developed to enable efficient synthesis of 2,4,6-trisubstituted and 2,6-disubstituted 1,3,5-triazines and 1,3-disubstituted 1,2,4-triazoles from amidines with trialkylamines, DMSO, and DMF as the reaction partners, respectively. This protocol features inexpensive metal catalyst, green oxidant, good functional group tolerance, and high regioselectivity, providing an efficient entry to those products that are challenging to prepare by traditional methods. A single-electron-transfer (SET) mechanism is proposed for these transformations