Dynamic Covalent Metathesis in the C=C/C=N Exchange between Knoevenagel Compounds and Imines

作者：Gu, Ruirui; Flidrova, Karolina; Lehn, Jean-Marie^*

来源：Journal of the American Chemical Society, 2018, 140(16): 5560-5568.

DOI：10.1021/jacs.8b01849

• VIRTUAL COMBINATORIAL LIBRARIES
• OLEFIN-METATHESIS
• NOBEL LECTURE
• SUPRAMOLECULAR CHEMISTRY
• ADAPTIVE CHEMISTRY
• ADDITIVE FORMATION
• 4-MEMBERED RINGS
• COMPLEX MATTER
• GENERATION
• ACID

Fast and reversible dynamic covalent C=C/C=N exchange takes place without catalyst in nonpolar solvents between barbiturate-derived Knoevenagel (Kn) compounds and imines. A detailed study of the reaction indicates that it proceeds by an associative organo-metathesis mechanism involving the formation of a four-membered ring azetidine intermediate by addition of the imine C=N group to the C=C bond of the Kn compound. This intermediate could be generated cleanly and stabilized at low temperature by condensation of the o,p-dinitrophenyl Kn derivative with the cyclic imine 1-azacyclohexene. It was characterized by extensive NMR and mass spectrometric studies. The process described represents a genuine dynamic covalent organo-metathesis through a four-membered ring adduct as intermediate. It paves the way for the exploration of a wide set of dynamic systems involving (strongly) polarized C=C bonds and various imines, extending also into covalent dynamic polymers and polymolecular assemblies.

• 出版日期2018-4-25
• 单位华东理工大学