New Trans-Chelating Ligands and Their Complexes and Catalytic Properties in the Mizoroki−Heck Arylation of Cyclohexene

New air-stable chelating diphosphine ligands, 1,8-bis(4-(diphenylphosphino)phenyl)anthracene (2) and 1,8-bis(4-(diphenylphosphino)-3,5-dimethylphenyl)anthracene (3), were synthesized from readily available starting materials. The examination of their coordination modes in Pd(II) and Rh(I) complexes by means of 1H, 13C, and 31P NMR spectroscopy and X-ray analysis revealed that 2 is mainly a trans-coordinating ligand but can also adapt smaller coordination angles, while 3 is “purely” trans-spanning and no formation of identifiable cis-chelated complexes was detected. The catalytic activity of the new compounds was tested in palladium-catalyzed Mizoroki−Heck reactions of aryl bromides with cyclohexene.