A polymeric ionic liquid catalyst for the N-formylation and N-methylation of amines using CO2/PhSiH3

•An ionic polymer was developed as a catalyst for the N-formylation and N-methylation of N-methylaniline using CO2.•A near-quantitative yield of N-formylation of N-methylaniline can be achieved under mild conditions.•N-formylation and N-methylation can be tuned by varying the reaction conditions.•The catalyst is stable, easy to use and can be recycled in a facile manner . We describe a polymeric ionic liquid (PIL) derived from trimethyl(p-vinylbenzyl)ammonium chloride ([VBTAm]Cl) that efficiently catalyzes the N-formylation of amines employing CO2 and PhSiH3 at room temperature with low catalyst loadings in near-quantitative yield. Under more forcing conditions N-methylated products can be selectively obtained. The PIL catalyst can be easily recovered and reused repeatedly without a decrease in activity. The reaction mechanism was studied in situ using high-pressure NMR spectroscopy and a tentative mechanistic cycle has been proposed.