Synthesis and reactivity of 2-aminophenylpalladium(II) complexes: Insertion reactions of oxygen and carbon monoxide into carbon-palladium bonds - Newexamples of "transphobia"

Mixtures of "Pd(dba)(2)" (dba = dibenzylideneacetone) and neutral ligands r eact with an excess of 2-iodoaniline to give [Pd(C6H4NH2-2)I(bpy)] (1) or t rans-[Pd(C6H4NH2-2)I(PR,),I [R=Ph (2a), p-tolyl (Tol) (2b), cyclohexyl (Cy) (2c), Me (2d)]. Complex 2a reacts with benzaldehyde to give trans-[Pd{C6H4 (N=CHPh)-2}I(PPh3)(2)] (3). Complexes 1-3 react with CO to give the inserti on compounds [Pd{C(O)C6H4NH2-2}I(bpy)] (4), trans[Pd{C(O)C6H4NH2-2}I(PR3)(2 )] IR = Ph (5a), Tol (5b), Cy (5c), Me (5d)] and trans-[Pd{C(O)C6H4N(=CHPh) -2}I(P-Ph-3)(2)] (6), respectively. Complexes 3, 4, 5a and 5b react with Tl OTf (OTf = CF;SO,) and atmospheric oxygen to give [Ph3PC6H4N=CHPh-2]OTf (7) , [Pd{kappa(2)C(O)C6H4NH2} (bpy) ]OTf (8) and [(R3P)(2)Pd(kappa(3)-mu(2)-NH 2C6H4CO2-2)Pd{kappa(2)C(O)C6H4NH2-2}(PR3)(2)](OTf)(2) [R = Ph (9a), Tol (9b )], respectively. When complexes 2a and 2b are treated with TlOTf under an atmosphere of CO, the cyclopalladated acyl complexes cis[Pd{kappa(2)-C(O)C6 H4NH2-2}(PR3)(2)]OTf [R=Ph (10a), ToI (10b)] are obtained. Complex 9a react s with an excess of PPh3 and atmospheric oxygen to give cis- [Pd{kappa(2)-O C(O)C6H4NH2-2}(PR3)(2)]OTf (11). The crystal structures of 2a, 3, 5d, 7 8 a nd 9a have been determined by X-ray diffraction studies.