Fig. 7: Catalytic mechanism.

a Two key steps in free diffusion fashion for the three-component aza-Darzens reaction: intermolecular nucleophilic attack of the C-C bond (key I) and intramolecular nucleophilic attack of the C-N bond (key II). b The graphical representations for the integration strategy of multiple lanthanide Lewis acidic sites and confined nanospace in supramolecular nanocage Zn2Er8L38 to promote two key steps of three-component aza-Darzens reaction. c The proposed mechanism for the three-component aza-Darzens reaction catalyzed by Zn2Er8L38 nanocage.