The palladium(II) / carbon monoxide-mediated biaryl formation from aryltellurium trihalides

Article abstract of DOI:10.1016/0022-328X(88)80378-4

Treatment of aryltellurium trihalides (ArTeX3: Ar=Ph, 4-BrC6H4, 4-MeC6H4, 4-MeOC6H4, 4-BuOC6H4, 4-PhOC6H4, 2-naphthyl; X=Cl,Br) with a palladium(II) salt in acetonitrile at 25 deg C affords, in good yields (29-78 percent), the corresponding biaryls (ArAr) either in the atmosphere or under 1 atm CO.The presence of CO accelerates this aromatic coupling significantly to produce some active palladium carbonyl species, the formation of which was confirmed by IR spectroscopy of Li2PdCl4 in acetonitrile solution under CO; a strong sharp absorption and a weaker sharp one appeared at 2140 and 1908 cm^-1, respectively, attributable to the ν(CO) of the (Pd-CO) species.Treatment with alkali after reaction was essential to producing the biaryls.