An efficient way for the N-formylation of amines by inorganic-ligand supported iron catalysis.

The first example of an inorganic-ligand supported iron(III) catalysed coupling of formic acid and amines to form formamides is reported. The pure inorganic catalyst (NH4)3[FeMo6O18(OH)6] (1), which consists of a central FeIII single-atomic core supported within a cycle-shaped inorganic ligand consisting of six MoVIO6 octahedra, shows excellent activity and selectivity, and avoids the use of complicated/commercially unavailable organic ligands. Various primary amines and secondary amines have been successfully transformed into the corresponding formamides under mild conditions, and the formylation of primary diamines has also been achieved for the first time. The Fe catalyst 1 can be reused several times without appreciable loss of activity. [ABSTRACT FROM AUTHOR]