Synthesis and structure of orthopalladated complexes derived from prochiral iminophosphoranes and phosphorus ylides

The iminophosphorane Ph2MePdouble bond; length as m-dashNPh (1) reacts with Pd(OAc)2 to give the orthopalladated [Pd(μ-Cl){C6H4(PPh(Me)double bond; length as m-dashNPh-κ-C,N)-2}]2 (2) as the racemic mixture, which reacts with Tl(acac) to give [Pd(acac){C6H4(PPh(Me)double bond; length as m-dashNPh-κ-C,N)-2}] (3). The X-ray structure of (3) has been determined by diffraction methods. The phosphorus ylide Ph2MePdouble bond; length as m-dashCHC(O)Ph (5) reacts with Pd(OAc)2 to give the dinuclear [Pd(μ-Cl){C6H4(PPh(Me)CHC(O)Ph-κ-C,C)-2}]2 (6) as a mixture of isomers. Complex (6) reacts with Tl(acac), PPh3 or AgClO4/dppe giving the mononuclear derivatives [Pd(acac){C6H4(PPh(Me)CHC(O)Ph-κ-C,C)-2}] (7), [PdCl{C6H4(PPh(Me)CHC(O)Ph-κ-C,C)-2}PPh3] (8) and [Pd{C6H4(PPh(Me)CHC(O)Ph-κ-C,C)-2}(dppe–P,P′)](ClO4) (9), as mixtures of stereoisomers with high diastereomeric excess.