The concept of metal-ligand bifunctionality can be employed for an efficient activation of N-H bonds by well-defined ruthenium amido complexes. An enantioselective catalytic aza-Michael reaction was developed on the basis of this process, which gives rise to indoline β-amino acids.
![Metal–ligand bifunctional activation and transfer of N–H bonds](https://www.iciq.org/wp-content/uploads/2014/03/Metalligand-bifunctional_4911.gif)