Chiral Amine Covalent Organic Cage Lingated with Copper for Asymmetric Decarboxylative Mannich Reaction

The efficient employment of chiral porous organic cages (POCs) for asymmetric catalysis is of great significance. In this work, we have synthesized a chiral N-rich organic cage constructed through chiral (S, S)-1,2-cyclohexanediamine and benzene-1,3,5-tricarbaldehyde utilizing dynamic imine chemistry according to the literature. Following reduction with NaBH4, the resulting amine-based POCs (RCC3) feature appended chiral diamine moieties capable of coordinating Cu2+ cations. This Cu2+ coordination provides RCC3 with excellent enantioselectivity as a supramolecular nanoreactor in asymmetric decarboxylative Mannich reactions, providing up to 94% ee of the product. We found that the spatial distribution of chiral amine sites and the coordination of Cu2+ in the RCC3 have a significant impact on catalytic activity, especially enantioselectivity. This work provides insights into the structure–function relationship within supramolecular catalytic systems