Synthesis Of Tertiary Ferrocenylamines And The Mechanistic Studies Of Their Ortho-mercuration, Cyclopalladation

The Reactions of ferrocenylcarboxaldehyde and series substituted anilines in mthanol at room temperature resulted in ferrocenylaldimines [(η5-C5H5)Fe(η5-C5H4CH=NC6H4-R)] ,R=4-MeO(a),4-Me(b),H(c), 4-Cl(d), 3-Cl(d), 4-NO2(e), 3-NO2(f),.in moderate yield. Reductions of these imines with sodium borohydride in methanol or lithium aluminum hydride in THF produced quantitative secondary ferrocenylamines [(η5-C5H5)Fe(η5-C5H4CH2-NHC6H4-R)],R = 4-MeO(a), 4-Me(b), H(c), 4-Cl(d), 3-Cl(d), 4-NO2(e), 3-NO2(f). Reductive methylation of secondary ferrocenylamines with sodium cyanoborohydride or direct reductive methylation of aldimine as mentioned above both gave out the corresponding tertiary ferrocenylamines [(η5-C5H5)Fe(η5-C5H4CH2-N(CH3)C6H4-R)], R=4-MeO(a), 4-Me(b), H(c), 4-Cl(d), 3-Cl(d), 4-NO2(e), 3-NO2(f). Ortho-mercuratation of these tertiary amines afforded orthomercurated complexes in which an intermolecular N-Hg coordination pattern was observed. However, with the increment of electron withdrawing ability of substituents in the tertiary amines, the trend of N-Hg coordination varied from intermolecular to intramolecular coordination. Cyclopalladation of these amines led to racemic cyclopalladated complexes in low yields. The stereoselective C-H activation was observed. The structures of four series compounds as mentioned before were characterized by elemental analysis, IR and 1H NMR. In addition, the structures of one secondary ferrocenylamine, five tertiary ferrocenylamines, three mercurated complexes and one palladium complex were also confirmed with X-Ray single crystal diffraction.