Copper-Catalyzed Trifunctionalization of Alkynes: One-Pot Assembly of Antifungal Benzofuro[3,2- <i>d</i> ]pyrimidine-Containing Fused Heterocycles

A copper-catalyzed, three-component tandem reaction for the synthesis of benzofuro[3,2-<i>d</i>]pyrimidine-containing fused heterocycles has been developed. This one-pot protocol efficiently couples terminal alkynes, salicylaldehydes, and α-aminoazoles through a sequential process involving A³ coupling and an intermolecular oxidative 1,2-difunctionalization of the alkyne. This strategy represents a rare example of alkyne trifunctionalization for the construction of polycyclic aromatic heterocycles. Notably, several synthesized derivatives exhibit promising antifungal activity against plant pathogenic fungi.