Development of Pd–Cu catalyzed cross-coupling of terminal acetylenes with sp2-carbon halides

The Pd-catalyzed cross coupling reactions between sp2-C halides and terminal acetylenes have been independently reported by Heck, Cassar and us in 1975. The former two methods have been developed as an extension of the Heck reaction to an acetylenic CH-bond. Ours has been discovered on the base of combination of Pd-catalyzed cross-coupling of sp2-C halides with terminal acetylenes and Cu-catalyzed alkynylation of metal complexes developed by us in the course of systematic studies on transition metal acetylide chemistry. The coupling reactions have been used extensively as a reliable method for the synthesis of eneyne-based acetylenic materials. Some recent advances of the coupling are also described.