Sustainable Polymer-supported Catalysts for Cascade Organic Synthesis: Mechanisms, challenges, and opportunities

Polymer-supported catalysts (PSCs) have emerged as versatile and sustainable platforms for enabling cascade organic transformations by uniting the selectivity of homogeneous catalysis with the recoverability and operational simplicity of heterogeneous systems. Through the strategic immobilization of catalytically active species onto engineered polymer matrices—including porous organic frameworks (POFs), cross-linked resins, and PEG-based supports—PSCs offer finely tunable environments that modulate catalyst accessibility, diffusion, and turnover efficiency. Recent advances demonstrate their ability to orchestrate complex multi-step processes such as oxidation–reduction sequences, C–C and C–X bond formations, and tandem cyclizations essential to fine chemical synthesis. This review surveys the mechanistic and structural features that dictate PSC performance across acid–base, transition-metal, and enzymatic catalysis, while critically addressing persistent limitations such as mass-transfer barriers, leaching, and catalyst deactivation. By integrating insights from catalyst design, sustainability metrics, and state-of-the-art applications, we highlight how polymer-tethering strategies can enhance selectivity, recyclability, and process economy, and identify emerging directions for developing next-generation PSCs tailored for scalable, green, and mechanistically informed cascade synthesis.