Coordination Chemistry and Catalytic Application of Bidentate Phosphaferrocene−Pyrazole and −Imidazole Based P,N-Ligands

The synthesis of new planar chiral P,N-ligands based on 3,4-dimethylphosphaferrocene and either pyrazole or 1-methylimidazole is described. The coordination chemistry of the hemilabile pyrazole derivatives 3a and 3b ( a features a methylene bridge between the heterocycles, b an ethylene bridge) was investigated and afforded complexes [Mo( 3 )(CO) 5 ], cis -[Mo( 3 ) 2 (CO) 4 ], [Cp*RuCl( 3 )], [Cp*Ru( 3 ) 2 ]OTf, [Cp*RuCl( 3 )(PPh 3 )], and [Pd(η 3 -allyl)( 3 )]PF 6 . Reaction of the imidazole derivatives 4a and 4b with [Pd(η 3 -allyl)Cl] 2 and TlPF 6 yielded [Pd(η 3 -allyl)( 4 )]PF 6 . The Pd complexes of 3 and 4 were tested in the catalytic asymmetric allylic alkylation reaction of 1,3-diphenylallyl acetate with sodium dimethylmalonate. X-ray structures of one Ru complex and one Pd complex of 3a were determined.