Palladium-Catalyzed Direct CH Arylation of Isoxazoles at the 5-Position

A palladium‐catalyzed direct arylation of isoxazoles with aryl iodides has been achieved. The CH bond at the 5‐position is activated selectively to give coupling products in moderate to good yields. This direct arylation was applied to the synthesis of a spiro‐type chiral ligand, which proved to be most effective to the palladium‐catalyzed tandem cyclization of a dialkenyl alcohol. Knock your ′sox′ off: A palladium catalyst promotes the cross‐coupling of isoxazoles with aryl iodides through the selective CH bond activation at the 5‐position of the heteroaromatic compound. The use of 1,2‐bis(diphenylphosphino)benzene as the ligand and silver fluoride as the activator was found to be crucial for this direct arylation. FG=functional group.