title: Phosphine Oxides as Stabilizing Ligands for the Palladium-Catalyzed Cross-Coupling of Potassium Aryldimethylsilanolates.
abstract: The palladium-catalyzed cross-coupling reaction of potassium (4-methoxyphenyl)dimethylsilanolate (K(+)1(-)) with aryl bromides has been demonstrated using triphenylphosphine oxide as a stabilizing ligand. Unsymmetrical biaryls can be prepared from a variety of aryl bromides in good yield with short reaction times. Qualitative kinetics studies compared effects of different phosphine oxides on the rate of cross-coupling and established the beneficial effect of these ligands in the reaction of electron-rich arylsilanolates. The improved yield and reproducibility of the cross-coupling of several bromides was demonstrated by direct comparison of reactions performed with and without triphenylphosphine oxide under non-rigorous exclusion of oxygen.
authors.affiliation: Roger Adams Laboratory, Department of Chemistry, University of Illinois, 600 S. Mathews Avenue, Urbana, Illinois 61801.
authors.forename: Scott E
authors.initials: SE
authors.lastname: Denmark
authors.forename: Russell C
authors.initials: RC
authors.lastname: Smith
authors.forename: Steven A
authors.initials: SA
authors.lastname: Tymonko