Studies On The Reactions Of The Aldehydes Or Imines Induced By The Lanthanide Compounds Containing The Ln-N Bond

In this dissertation, the reactions of the aldehydes or imines with other organic compounds induced by the lanthanide complexes containing the Ln-N bond were studied. The dissertation covers the studies on the Cross-Aldol reactions of cycloalkanone with aromatic aldehydes, the disproportionation reaction of the aldehydes and the Mannich reactions of the imines. There are mainly three parts in the dissertation.Firstly, under solvent-free and microwave irradiation conditions, the corresponding E, E' -α, α' -bis(substituted benzylidene)cycloalkanones were prepared in high yields by the Cross-Aldol reactions of cyclopentanone or cyclohexanone with aromatic aldehydes catalyzed by the lanthanide amides [(Me₃Si)₂N]₃Ln(μ-Cl)Li(THF)₃. The reactions produce the products in relative low yield and require long time when they were performed in various solvents without microwave irradiation. Thus, the procedure provides a simple and a green synthetic methodology.Secondly, We for the first time found that aromatic aldehydes could be directly converted to the corresponding amides and alcohols in good to excellent yields by treatment of aromatic aldehydes with lithium amide LiN(SiMe₃)₂ in the presence of catalytic lanthanide chlorides LnCl₃ or by treatment of aromatic aldehydes with stoichiometric amount of lanthanide amides [(Me₃Si)₂N]₃Ln(μ-Cl)Li(THF)₃ at ambient temperature The effects of solvents, substitutents on the phenyl ring, and lanthanide metals on the reaction have been examined. The mechanism of the Cannizzaro-type disproportionation reaction was proposed based on the experimental results. Through the Cannizzaro-type disproportionation reaction, other amides could be synthesized.Thirdly, the yttrium amide [(Me₃Si)₂N]₃Y(μ-Cl)Li(THF)₃ was found to be a good catalyst for the nitro-Mannich reaction of nitromethane with sulfonylimines under mild conditions. And under solvent-free condition, the catalytic activity of the yttrium amide [(Me₃Si)₂N]₃Y(μ-Cl)Li(THF)₃ for the Mannich reaction of the cyclohexanone with sulfonylimines was also investigated. Compared with the traditional methods, the reaction has the advantages of available and economical materials, mild reaction conditions and higher yields.