Palladium-catalyzed regiocontrolled alpha-arylation of trimethylsilyl enol ethers with aryl halides.

Inter- and intramolecular arylations of trimethylsilyl enol ethers with aryl halides are accomplished regiospecifically in the presence of a palladium catalyst and tributyltin fluoride in refluxing benzene or toluene. The optimal catalyst system called for the use of Pd2(dba)3 and tri-tert-butylphosphine in ca. 1:2 ratio. Aryl iodides, bromides, and chlorides are all effective arylation partners in this reaction. [reaction: see text]