Polymer Anchored Cinchona Alkaloids: Synthesis and their Applications in Organo-Catalysis.

Cinchona alkaloids are naturally occurring chiral molecules that have emerged as catalysts in asymmetric organocatalysis especially in enantioselective transformations because of their inherent chirality and unique structural features. Immobilizing these alkaloids on polymeric supports has significantly influenced their use in catalysis. Polymer-anchored cinchona alkaloids combine the catalytic efficacy of cinchona derivatives with additional benefits of polymer chain, such as ease of recovery, recyclability, reusability, and reduced environmental impact. These polymer-supported cinchona alkaloids have found wide applications in enantioselective reactions such as Michael addition, aldol condensations, Henry reaction, dimerization reaction, dihydroxylation, and benzylation. Various strategies have been employed for anchoring cinchona alkaloids onto polymers, including covalent attachment of alkaloids in the polymer side chain or main chain, and ionic attachment of alkaloids via quaternization in the main chain or side chain of polymer. This review focuses on the various synthetic methodologies for the preparation of polymer-anchored cinchona alkaloids and their application in numerous asymmetric transformations.