Well-Defined Phosphine-Free Iron-Catalyzed <i>N</i>-Ethylation and <i>N</i>-Methylation of Amines with Ethanol and Methanol

Abstract

An iron(0) complex bearing a cyclopentadienone ligand catalyzed N-methylation and N-ethylation of aryl and aliphatic amines with methanol or ethanol in mild and basic conditions through a hydrogen autotransfer borrowing process is reported. A broad range of aromatic and aliphatic amines underwent mono- or dimethylation in high yields. DFT calculations suggest molecular hydrogen acts not only as a reducing agent but also as an additive to displace thermodynamic equilibria.