Chiral Phosphoric Acid-Functionalized Three-Dimensional Covalent Organic Frameworks with Exceptional Chemical Stability for Asymmetric Catalysis.

The design of three-dimensional covalent organic frameworks (3D COFs) incorporating chiral phosphoric acids represents a promising strategy to enhance enantioselectivity in asymmetric catalysis while providing good framework stability, but their development remains a significant challenge. Herein, by using the multivariate approach, we report the construction of two highly crystalline chiral phosphoric acid-functionalized 3D COFs with the 4-fold interpenetrated qtz topology. Notably, the resulting frameworks exhibit exceptional chemical stability, remaining crystallinity even in 12 M HCl, saturated NaOH, and boiling water. Moreover, benefiting from the confined chiral porous architecture, these COFs deliver good activity, enantioselectivity, and recyclability in asymmetric N, N-acetalization reactions, significantly outperforming their homogeneous analogues. This work not only reports a highly stable chiral phosphoric acid-functionalized 3D COF for asymmetric catalysis, but also provides a foundation for constructing robust, reusable heterogeneous chiral organocatalysts.