Orthopalladation of phosphorus ylides in endo position with bidentate ligands

► The reaction of dinuclear complexes [Pd2{κ2(C,C)-C6H4(PPh2CHC(O)C6H5R}2(μ-Cl)2] (R = Ph, NO2, Br) with silver trifluoromethylsulfonate and bidentate ligands (L = phen, bipy, dppe, dppp) led to the synthesis of new mononuclear orthopalladated complexes in endo position [Pd{κ2(C,C)-C6H4(PPh2CHC(O)R}L](OTf) (2a-5a), (2b-5b) and (2c-5c), in which the five-membered Pd-C-P-C-C metallacycle remains stable. ► The compounds were characterized by elemental analysis and spectroscopic techniques. ► The crystal structures of orthopalladated complexes [Pd{κ2(C,C)-C6H4(PPh2CHC(O)Br}phen](OTf) (2c) and [Pd{κ2(C,C)-C6H4(PPh2CHC(O)Br}bipy](OTf) (3c) have been determined by single crystal X-ray diffraction. ► Orthometalation and ylidic C-coordination were demonstrated by the X-ray diffraction study of 2c and 3c.