Regioselective control by a catalyst switch in palladium-catalyzed benzylallylation of arylethylidene malononitriles

Regioselective control by a catalyst switch in palladium-catalyzed benzylallylation of arylethylidene malononitriles (α-benzyl-β-allylation versus α-allyl-β-benzylation) is described. The three-component reaction of 2-(bromomethyl)naphthalenes, arylethylidene malononitriles, and allyltributylstannane proceeds smoothly with palladium nanoparticles as a catalyst to provide α-benzyl-β-allylation products in good yields. The regioselectivity of the benzylallylation reaction is completely overturned with Pd(PPh3)4 as the catalyst instead of palladium nanoparticles to obtain α-allyl-β-benzylation products in moderate to good yields.