Abstract Labile iron complexes (e.g., [Fe III(bpy) 2] MeCN 3+, [Fe II(bpy) 2] MeCN 2+, [Fe III(H 2O) 6] MeCN 3+, and [Fe II(H 2O) 6] MeCN 2+) in base-free acetonitrile activate dioxygen for the direct oxygenation of N,N- and N-alkylated amines to form N-dealkylated products and corresponding aldehydes. N,N-dimethylaniline (DMA) is oxidized to N-methylaniline (MA) and formaldehyde as well as to N-methylanilide. Formaldehyde and the excess of substrate undergo condensation reaction to produce 4,4′-methylenebis( N,N-dimethylaniline) (MBDME). Small amounts of N-methylformanilide (MF) and formanilide are also formed during oxidation of N,N-dimethylaniline and N-methylaniline respectively. Iron(III) catalysts are reduced by the substrate to iron(II), which activates dioxygen. Dioxygen activation step is preceded by the equilibrium reaction between iron(II) catalyst and substrate.