Single-Handed Helical Poly(quinoxaline-2,3-diyl)s Bearing Achiral 4-Aminopyrid-3-yl Pendants as Highly Enantioselective, Reusable Chiral Nucleophilic Organocatalysts in the Steglich Reaction.

Helically chiral poly(quinoxaline-2,3-diyl)s bearing 4-aminopyrid-3-yl pendants were synthesized as new helical-polymer-based chiral nucleophilic organocatalysts. The obtained chiral nucleophilic polymer catalysts exhibited high catalytic activity, enantioselectivity, and reusability in asymmetric Steglich rearrangement of oxazolyl carbonate to C-carboxyazlactone. The polyquinoxaline-based, helically chiral DMAP catalyst mediated intramolecular acyl transfer selectively, by contrast with known small-molecule-based chiral organocatalysts, which also mediate intermolecular acyl transfers.