Palladium Iminoacyl Imine Complexes: Strategies toward Imine Insertion

The syntheses and characterization of a number of palladium complexes containing imine and/or iminoacyl groups are reported. Our strategies toward the insertion of imines into palladium iminoacyl complexes are outlined. The imine complexes [Pd(Me)(L 2 ){N(R′)═C(H)Ph}]X (where L 2 = dppe, dppp, dppf; R′ = Ph, Me, Bz; and X = BF 4 or OTf) were prepared and fully characterized. [Pd(Me)(dppe){N(Ph)═C(H)Ph}]BF 4 ( 1 ) and [Pd(Me)(dppp){N(Ph)═C(H)Ph}]OTf ( 4 ) were structurally characterized by X-ray crystallography. The iminoacyl-imine complexes [Pd{C(Me)═NXyl} (L 2 ){ N═C(Me)OCH 2 CH 2 }]BF 4 (L 2 = dppe, 12; dppp, 13 ) were prepared. The bis-imine complex [Pd(dppe){ N═C(Me)OCH 2 CH 2 } 2 ][BF 4 ] 2 ( 14 ) resulting from disproportionation of 12 was also prepared and structurally characterized. Protonation of the iminoacyl fragment provided iminoacyl imine complex [Pd{C(CH 3 )═N(H)Xyl}(dppe){N(Bz)═CPhH}][BF 4 ] 2 ( 17 ), which was sufficiently stable to be structurally characterized, providing some insight into the coordination of these fragments to palladium.