Catalyst-free N-methylation of amines using CO2

Abstract

Recently, utilizing CO₂ as a methylation reagent to construct functional chemicals has attracted significant attention. However, the conversion of CO₂ is still a challenge due to its inherent inertness. In this study, we have developed a catalyst-free N-methylation of amines to prepare numerous methylamines using CO₂ as a methyl source. By utilizing 2 eq. PhSiH₃ as the reductant, amines could undergo N-methylation under 1 atm of CO₂ in DMF at 90 °C. Aliphatic and aromatic amines were compatible, generating the desired products in up to 95% yield.