Synthesis of Highly Substituted 1,3-Butadienes by Palladium-Catalyzed Arylation of Internal Alkynes

Four molecules are coupled together by the single treatment of aryl boronic acids with alkynes in the absence or presence of iodobenzene under palladium catalysis to afford 1,4‐diaryl‐1,3‐butadienes as the major product. Addition of a silver salt as oxidant and/or base effectively enables the selective catalytic production of the π‐conjugated compounds.