1,1′-Bis(oxazolinyl)ferrocene-based palladium catalysts: Synthesis, X-ray structures and applications in Suzuki and Heck coupling reactions

1,1′-Bis(oxazolinyl)ferrocene-based palladium dichloride complexes 2a and 2b were synthesized. X-ray single-crystal diffraction analyses showed that they are of the N,N′-chelating type, and that the coordination mode of 2a, which has an isopropyl group, is of the cis type, whereas that of 2b, which has a tert-butyl group, is the trans one. These two complexes were employed as catalysts for Suzuki and Heck reactions, and showed high catalytic activities in coupling reactions with various aryl halides and counterparts (phenylboronic acid or n-butyl acrylate). Particularly, the catalyst 2a afforded the coupled product of aryl bromide with phenylboronic acid at room temperature.