Heterogeneous Organic Polymers Embedded with Chiral Bisoxazoline Ligands for Photoinduced Cu-Catalyzed Asymmetric Cyanation

Chiral bisoxazoline (box) ligands with indene groups at C4 and C5 are highly potent in asymmetric catalysis, but face challenges in terms of cost and recyclability. To address this, we have designed polystyrene-supported box ligands by modifying the indene moiety instead of the traditional methylene bridge. This design preserves the necessary steric environment for copper coordination, enabling high efficiency and excellent enantioselectivity as examined in photoinduced asymmetric cyanation reactions. The resulting copper complexes are robust and recyclable, maintaining performance over five cycles. This approach provides a sustainable and practical solution for asymmetric catalysis with chiral box ligands.