Heterogeneous Organocatalytic Synthesis of Propargylic Esters Using a Polymer‐Supported N ‐Heterocyclic Carbene

The conversion of carbon dioxide into high‐value chemical scaffolds is a central challenge in modern green chemistry. In this study, we report the first heterogeneous, metal‐free organocatalytic protocol for the three‐component synthesis of propargylic esters from terminal alkynes, CO 2 , and alkyl halides, employing a vinyl addition polynorbornene (VA‐PNB)‐supported N ‐Heterocyclic Carbene (NHC) precatalyst. Optimization studies revealed that the immobilized tert ‐butyl‐substituted NHC outperforms other structural variants, promoting the carboxylative coupling under metal‐free conditions. The catalyst can be recovered by filtration and regenerated through mild acid treatment. A gradual decrease in activity is observed upon reuse due to retained potassium carbonate used as a base in the reaction, but the catalyst activity can be recovered with further washing. The method demonstrates excellent chemoselectivity with cinnamyl‐type electrophiles, offering a sustainable and operationally simple approach to valuable functionalized esters, without the need for transition metals.