Reactions of palladium(II) with organic compounds. Part III. Reactions of aromatic iodides in basic media

Abstract

Iodobenzene, some monosubstituted iodobenzenes, and 2,5-dimethyliodobenzene couple through the iodine-bearing carbon atom to form biaryls, and also undergo protiodeiodination to a small extent, when treated with a catalytic quantity of palladium(II) acetate in triethylamine or tri-n-butylamine at 100°; in the latter solvent the corresponding aryl propyl ketones are also formed. It is suggested that biaryl formation involves the interaction of two arylpalladium species, and evidence is adduced that such a species reacts with an intermediate enamine to give a ketone or with adventitious water to yield a protiodeiodinated product.