Micellar N-Heterocyclic Carbene-like Organic Catalysis from Polymeric Nanoreactors Immobilizing Benzimidazolium Acetate Motifs in Their Core

Abstract

N-Heterocyclic carbenes (NHCs) are among the most studied reactive species in organic chemistry. They are widely employed as ligands for transition metal catalysts and also display a rich chemistry as stoichiometric reagents and organocatalysts. Nevertheless, their sensitivity to air and moisture still limits their widespread adoption in synthesis. Taking inspiration from processive enzyme-catalyzed reactions, we have tackled this challenge by designing efficient and recyclable polymeric nanoreactors immobilizing water-compatible benzimidazolium acetate motifs in their core and showing catalytic activity akin to that of NHC units. The nanoreactors’ ability to perform micellar organocatalysis in water is established through benchmark NHC-catalyzed reactions, including benzoin condensation, transesterification, and cyanosilylation. This NHC-like micellar organocatalysis proceeds with exceptionally high activity due to a compartmentalization effect and avoids both costly purification steps and the need for solvents to isolate reaction products.