Preparation of unsymmetrical biaryls by Pd(II)-catalyzed cross-coupling of aryl iodides.

The Ullmann homo- and cross-couplings of aryl iodides are carried out to afford symmetrical and unsymmetrical biaryls in moderate to good yields in a catalytic system of Pd(OAc)(2)/K(2)CO(3)/MeCOEt. The high selectivity of unsymmetrical biaryl products in cross-couplings mainly depends on the reactivity difference between two iodoarene substrates and their employed ratios.