Synthesis and structure of new oxapalladacycles with a Pd-O bond

Reaction of the arylpalladium complex [Pd(2-C6H4CH2OSi-t-BuMe2)(PPh3)(2)I] (9) with n-Bu4NF gave the oxapalladacycle dimer [Pd(2-C6H4CH2O)I(PPh3)](2) (7). Similarly, [Pd(2-C6H4CH2O)I(AsPh3)](2) (11) was obtained by reaction of the arylpalladium complex [Pd(2C(6)H(4)CH(2)OSi-t-BuMe2)(AsPh3)(2)I] (10) with n-Bu4NF. 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(3H)-isobenzofuranylidenethanamine (18). Reaction of [Pd(2-C6H4R)(PPh3)(2)X] (R = CHO, X = Br, 21; R = CO2H, X = Br, 24a; R = CO2H, X = I, 24b) with Ag2CO3 or Cs2CO3/AgBF4 afforded the tetrameric complex [Pd(2-C6H4CO2)(PPh3)](4) (22), whose structure was confirmed by X-ray diffraction.