Copper-Mediated Direct Cross-Coupling of 1,3,4-Oxadiazoles and Oxazoles with Terminal Alkynes

Copper-mediated direct cross-coupling of 1, 3, 4-oxadiazoles and oxazoles with terminal alkynes has been reported. The transition-metal-mediated direct functionalization reactions of C-H bonds have attracted significant interest in modern organic chemistry. The mixture was heated at 120°C, and the slow addition of 1 hour of a solution of phenylacetylene in DMAc (1.0 mL) as then started. The cross-coupling using CuCl2/DMEDA system. Thus, the desired 2-alkynyl-5-aryloxazoles were obtained by performing the reaction in a higher ratio at 150°C with DMSO as solvent. The oxadiazoles with various substituents at the 2-position were also available for use. 4- Methyl-, 4-methoxy-, 4-trifluoromethyl-, and 4-chloro- phenyl-1, 3, 4-oxadiazoles coupled with 4-MeC5H4, to furnish compound.