Cycloaddition of Aziridine with CO₂/CS₂ Catalyzed by Amidato Divalent Lanthanide Complexes

Area of Science:

• Organometallic Chemistry
• Catalysis
• Synthetic Organic Chemistry

Background:

• Cycloaddition reactions are crucial for synthesizing heterocyclic compounds.
• Lanthanide complexes are increasingly explored as catalysts in organic synthesis.
• Efficient methods for synthesizing oxazolidinones and thiazolidine-2-thiones are in demand.

Purpose of the Study:

• To investigate the catalytic activity of novel lanthanide amides in cycloaddition reactions.
• To explore the use of amidato lanthanide amides as catalysts for the reactions of aziridines with CO2 and CS2.
• To achieve mild reaction conditions and good functional group tolerance.

Main Methods:

• Synthesis of amidato lanthanide amide complexes: {Ln[N(SiMe3)2]THF}2 and {L3Eu[N(SiMe3)2]THF}{L32Eu(THF)2}.
• Application of these complexes as catalysts in cycloaddition reactions of aziridines with carbon dioxide (CO2) or carbon disulfide (CS2).
• Characterization of the reaction products: oxazolidinones and thiazolidine-2-thiones.

Main Results:

• Amidato lanthanide amides were successfully employed as catalysts for the first time in these cycloaddition reactions.
• Oxazolidinones and thiazolidine-2-thiones were obtained in good to excellent yields.
• The catalytic system demonstrated good functional group tolerance under mild reaction conditions.

Conclusions:

• Amidato lanthanide amides are effective catalysts for the cycloaddition of aziridines with CO2 and CS2.
• This methodology provides a mild and efficient route to valuable heterocyclic compounds.
• The findings expand the scope of lanthanide catalysis in organic synthesis.