A highly active catalyst system based upon a biaryl monophosphine ligand, XPhos, for the palladium-catalyzed Stille reaction has been developed. This method allows for the coupling of aryl chlorides with a range of tributylarylstannanes to produce the corresponding biaryl compounds in good to excellent yields (61–98%) in short reaction times (4 h). Palladium(II) acetate [Pd(OAc)2] and XPhos in a 1:1.1 ratio were milled into a fine powder that was used as pre-catalyst for these reactions.
“Palladium-Catalyzed Stille Cross-Coupling Reaction of Aryl Chlorides using a Pre-Milled Palladium Acetate and XPhos Catalyst System”, Adv. Synth. Cat., 2008, 350(7-8), 957-961.