Highly active Pd(II) catalysts with trans-bidentate pyridine ligands for the Heck reaction.
[reaction: see text] The air-, water-, and heat-stable palladium(II) complexes 2a and 2b are prepared by the reaction of palladium(II) salts with the new trans-bidentate nitrogen ligands, 1,2-bis(2-pyridylethynyl)benzenes. The structure of complex 2a has been confirmed by X-ray structure analysis. The complexes efficiently catalyze the Heck olefination of aryl iodides and provide a good yield under phosphine-free conditions. The reaction is very sensitive to the nature of the chelating ligand.
The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka, Ibaraki, Osaka 567-0047, Japan. kawano@sanken.osaka-u.ac.jp
Tomikazu
T
Kawano
Tatsuji
T
Shinomaru
Ikuo
I
Ueda