Palladium-Catalyzed Regioselective Heck Coupling of Alkynes with Aryl Iodides for the Synthesis of Trisubstituted Allenes.

A utility approach toward trisubstituted allenes through Pd-catalyzed alkynyl Heck coupling reaction of alkynes and aryl iodides is reported. This process proceeded via regioselective carbopalladation of 1-aryl-1-alkynes to give alkenyl palladium species, which undergo β-hydride elimination to provide 1,1-diarylallenes in 25-71% yields. This method features unique regioselectivity and high functional group compatibility.