An unparalleled copper(I)-catalyzed synthesis of 1,3,4-oxadiazoles from tertiary amines in one step has been described. The one-pot reactions involving (N-isocyanimine)triphenylphosphorane , tertiary amines , and carboxylic acids resulted in the formation of 1,3,4-oxadiazoles in moderate to good yields through a consecutive oxidative Ugi/aza-Wittig reaction, enabling direct functionalization of sp3 C-H bonds adjacent to the nitrogen atom. This method offered several notable advantages, including mild reaction conditions, ligands free, exceptional productivity and high functional group tolerance. The preliminary biological evaluation demonstrated that compound 4f inhibited hepatoma cells efficiently, suggesting potentially broad applications of the approach for synthesis and medicinal chemistry.

A novel and efficient four-component dicyclization strategy has been developed for one-step constructing diverse antibacterial 3-(1,3,4-oxadiazol-2-yl)isoindolin-1-ones under very mild base-free and metal-free conditions without other additives. This one-pot process underwent two consecutive cyclization reactions including tandem Ugi/aza-Wittig reaction and N-acylation by utilizing (N-isocyanimine)triphenylphosphorane, methyl 2-formylbenzoate, primary amines, and carboxylic acids. The method was conferred its favorable characteristics, including ambient temperature conditions, one-step synthesis, without any additives, facile gram-scale synthesis, and good yields.