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/K₂CO₃/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.