Efficient and chemoselective direct reductive amination of aromatic aldehydes catalyzed by oxo-rhenium complexes containing heterocyclic ligands

Article abstract of DOI:10.1016/j.tet.2013.08.016

This work describes the catalytic activity of 17 oxo-rhenium complexes containing heterocyclic ligands in the direct reductive amination of 4-nitrobenzaldehyde with 4-chloroaniline, using phenylsilane as reducing agent. In general, all of the catalysts tested gave excellent yields of the secondary amine, although, the best result was obtained with the catalytic system PhSiH₃/ReOBr₂(Hhmpbta)(PPh₃) (2.5 mol %). This system was also applied to the synthesis of a large variety of secondary amines in good to excellent yields and tertiary amines in moderate yields, with tolerance of different functional groups.