N-Heterocyclic carbene-based porous polymer macroligand for the Ni-catalyzed C-H arylation of benzothiophenes

A porous organic polymer (POP) with imidazolium functionality ( IM-POP ) has been synthesized through radical polymerization. N-Heterocyclic carbene (NHC) has been generated from an imidazolium moiety via base treatment followed by coordination of nickel salt, giving access to a single-site Ni-NHC catalyst inside the polymeric network. The NiCl 2 @NHC-POP was found to heterogeneously catalyze the direct selective C2-H arylation of (benzo)thiophenes using various aryl electrophiles with a turnover number (TON) up to 75, reaching cumulative TON of ca. 400 after recycling for six consecutive runs. A novel single-site Ni(NHC) catalyst embedded within a porous polymer has been developed for the heterogeneous direct C-H arylation of (benzo)thiophenes with unprecedented stability and recyclability.