A simple route to novel palladium(II) catalysts with oxazolin-2-ylidene ligands

Novel palladium(II) complexes with oxazolin-2-ylidene ligands have been synthesized via direct reaction of palladium acetate and oxazolium salts, prepared in turn by alkylation of oxazole with methyl iodide or benzylic bromides. The resulting complexes have been characterized and used as catalysts in Heck coupling reactions of aryl bromides, where they exhibit remarkable catalytic activity, higher than that of the closely related bis-imidazolin- 2-ylidene and bis-benzothiazolin-2-ylidene complexes.