ABSTRACT NHC@Fe 3 O 4 , a robust heterogeneous organocatalyst, is fabricated by grafting an organophosphonic acid‐functionalized N ‐heterocyclic carbene (NHC) precursor onto Fe 3 O 4 nanoparticles. Detailed spectroscopic, microscopic, and structural analyses establish the successful surface functionalization of Fe 3 O 4 NPs and the uniform distribution of the precursor imidazolium moieties over Fe 3 O 4 nanoparticles of average diameter 10 nm. The resulting hybrid material NHC@Fe 3 O 4 acts as an efficient heterogenous organocatalyst in the oxidative esterification of benzaldehydes with aryl boronic acids under mild conditions and exhibits reasonably broad functional group tolerance. The catalyst's magnetic nature enables facile separation using an external magnet, while its robust characteristics facilitate consistent organocatalytic efficacy over at least four reuse cycles without any notable leaching or loss of performance. This work highlights a sustainable approach to design heterogenous organocatalyst by immobilizing organocatalytically active moieties over recyclable magnetic support and thereby promote waste reduction and operational simplicity.
Kashyap et al. (Thu,) studied this question.