Conversion of Imines into C,N-Dimagnesiated Compounds and Trapping with Electrophiles. One-Pot Access to 1-Azaspirocyclic Framework
Vincent Gandon, Philippe Bertus, Jan Szymoniak*
*Réactions Sélectives et Applications, CNRS and Université de Reims, 51687
Reims Cedex 2, France, Email: jan.szymoniak
univ-reims.fr
V. Gandon, P. Bertus, J. Szymoniak, Synthesis, 2002, 1115-1120.
DOI: 10.1055/s-2002-31962
Abstract
Under selected conditions, the Zr-catalyzed reaction of EtMgCl with imines produces C,N-dimagnesiated compounds, which can be further trapped with electrophiles. The overall transformation provides a new route to bifunctional or cyclic nitrogen-containing compounds such as 1-azaspirocyclic γ-lactams, pyrrolidines and azetidines.
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Details
The document describes a one-pot procedure for converting imines into C,N-dimagnesiated compounds using a Zr-catalyzed reaction with EtMgCl, followed by trapping with electrophiles to form bifunctional or cyclic nitrogen-containing compounds. This method provides a new route to synthesize 1-azaspirocyclic frameworks, including β-lactams, pyrrolidines, and azetidines. The reaction mechanism involves the formation of a zirconocene-ethylene complex, which reacts with imines to produce an azazirconacyclopentane intermediate. Subsequent reactions with EtMgBr lead to the formation of the dimagnesiated compound, which can be further reacted with various electrophiles to yield the desired products. The study highlights the importance of reaction conditions, such as the concentration of Grignard reagents and the choice of solvent, in optimizing the yield and selectivity of the desired products. The method allows for the efficient synthesis of complex nitrogen-containing molecules, which are valuable in the development of biologically active compounds. The document also includes detailed experimental procedures and characterization data for the synthesized compounds.
Key Words
Grignard reagents, benzylamines, azetidines, pyrrolidines, γ-lactams, imines, spiro compounds, zirconium
ID: J66-Y2002-1560
