Synthesis of substituted biaryls via Suzuki, Stille and Hiyama cross-coupling and homo-coupling reactions by CN-dimeric and monomeric ortho-palladated catalysts

The catalytic activity of dimeric [Pd{C6H2(CH2CH2NH2)-(OMe)2,2,3}(-Br)]2 and monomeric [Pd{C6H2(CH2CH2NH2)-(OMe)2,2,3}Br(PPh3)] complexes as efficient, stable and air- and moisture-tolerant catalysts was investigated in the Suzuki, Stille and Hiyama cross-coupling and homo-coupling reactions of various aryl halides. Substituted biaryls were produced in excellent yields in short reaction times using catalytic amounts of these complexes. The monomeric complex was demonstrated to be more active than the corresponding dimeric catalyst for the cross-coupling reaction of unreactive aryl bromides and chlorides. The combination of homogeneous metal catalysts and microwave irradiation gave higher yields of products in shorter reaction times. Copyright (c) 2013 John Wiley & Sons, Ltd.