SYNTHESIS OF ARYLACETYLENE AND VINYLACETYLENE DERIVATIVES BY COPPER-CATALYZED REACTION OF ARYL AND VINYL IODIDES WITH TERMINAL ALKYNES

The coupling reaction of aryl iodides with terminal alkynes by using a catalyst system of CuI-PPhs in the presence of K2CO3 as base gives the corresponding arylated alkynes in excellent yields. Addition of PPh3 is essential for the reaction to proceed catalytically. Vinyl iodides also react smoothly with the alkynes to give enyne compounds with retention of the configurations. While DMF and DMSO can be used as solvents, DMSO is found to be effective for the reaction with aliphatic terminal alkynes. A reaction mechanism involving initial formation of copper acetylide species coordinated by PPh3 followed by reaction of aryl and vinyl iodides is proposed.