Syntheses, Characterization and Catalytic Application of Palladacycles Containing Phosphane or Phosphane Oxide Functionalities

The preparation of ligand precursors PhN=C(CMe 2 )(NPh)C=N(CH 2 ) 2 PPh 2 ( 1 ) and PhN=C(CMe 2 )(NPh)C=N(CH 2 ) 2 P(O)Ph 2 ( 2 ) are described. Treatment of 1 or 2 with 1 mol equiv. Pd(OAc) 2 affords orthometallated palladium(II) complexes [PhN=C(CMe 2 )(N‐η 1 ‐Ph)C=N(CH 2 ) 2 PPh 2 ]Pd(OAc) ( 3 ) as a mononuclear complex or {[PhN=C(CMe 2 )(N‐η 1 ‐Ph)C=N(CH 2 ) 2 P(O)Ph 2 ]Pd(OAc)} 2 ( 4 ) as an acetate‐bridged dinuclear complex, respectively. Reaction of 3 with excess LiCl in methanol affords a mononuclear palladium(II) complex [PhN=C(CMe 2 )(N‐η 1 ‐Ph)C=N(CH 2 ) 2 PPh 2 ]PdCl ( 5 ). The crystal and molecular structures are reported for compounds 3 – 5 . Application of these novel palladacyclic complexes to the Suzuki and Heck reactions with aryl halide substrates was examined. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)