Mesopore-Confined Self-Assembly of Chiral Supramolecular Nanohelices as Highly Durable Asymmetric Catalysts

Chiral supramolecular catalysts (CSCs) have been established to possess favorable catalytic efficiency and enantioselectivity. However, their intrinsic drawbacks of severe organic solvent dependency and poor thermal stability of supramolecular self-assembled nanostructures largely limit their practical applications. Herein, we demonstrate that highly durable supported CSCs self-assembled from l-phenylglycine-based amphiphiles can be obtained by introducing mesoporous materials (such as carbon or silica with varied pore sizes) through a mesopore-confined self-assembly strategy. The resulting supported CSCs can be desolvated and annealed at temperatures higher than 100 °C while maintaining the self-assembled nanostructure and supramolecular chirality. Using the Diels–Alder reaction between aza-chalcone and cyclopentadiene as an example, the annealed mesoporous material-supported CSCs (loading Cu(II) ions as catalytic active centers) can display catalytic enantioselectivity with 94% enantiomeric excess (ee) in a methanol/water solvent and 84% ee in pure water as a more eco-friendly solvent, while the unsupported counterparts do not show any enantioselectivity in both solvents. The developed mesopore-confined self-assembly strategy provides a viable approach for the facile and scalable preparation of highly durable supported CSCs that can be potentially utilized in practical applications.