Ruthenium-Amido Complexes: Synthesis, Structure, and Catalytic Activity in Olefin Metathesis

Unprecedented amido derivatives of the first‐, second‐, and third‐generation Grubbs ruthenium catalysts were prepared, characterized, and tested in ring‐closing metathesis (RCM) of model dienes. In the ruthenium–amide (formally: 2‐ruthenaindole) form, these complexes exhibit nearly no activity in RCM. However, a dramatic increase of activity was observed upon in situ activation with an ethereal solution of HCl (see figure).