Synthesis and Structure of New Oxapalladacycles with a Pd−O Bond

Reaction of the arylpalladium complex [Pd(2-C 6 H 4 CH 2 OSi- t -BuMe 2 )(PPh 3 ) 2 I] ( 9 ) with n -Bu 4 NF gave the oxapalladacycle dimer [Pd(2-C 6 H 4 CH 2 O)I(PPh 3 )] 2 ( 7 ). Similarly, [Pd(2-C 6 H 4 CH 2 O)I(AsPh 3 )] 2 ( 11 ) was obtained by reaction of the arylpalladium complex [Pd(2-C 6 H 4 CH 2 OSi- t -BuMe 2 )(AsPh 3 ) 2 I] ( 10 ) with n -Bu 4 NF. The structure of dimer 7 was confirmed by single-crystal X-ray diffraction. Reaction of 7 or 11 with the bidentate ligands 1,1‘-bis(diphenylphosphino)ferrocene and 1,10-phenanthroline gave the monomeric oxapalladacycle complexes 16 and 17 . Complex 7 inserts tert -butyl isocyanide to form 1,1-dimethyl- N -1(3 H )-isobenzofuranylidenethanamine ( 18 ). Reaction of [Pd(2-C 6 H 4 R)(PPh 3 ) 2 X] (R = CHO, X = Br, 21; R = CO 2 H, X = Br, 24a; R = CO 2 H, X = I, 24b ) with Ag 2 CO 3 or Cs 2 CO 3 /AgBF 4 afforded the tetrameric complex [Pd(2-C 6 H 4 CO 2 )(PPh 3 )] 4 ( 22 ), whose structure was confirmed by X-ray diffraction.