Probing of the ligand anatomy: Effects of the chelating alkoxy ligand modifications on the structure and catalytic activity of ruthenium carbene complexes

Structural modifications of the Hoveyda-Grubbs ruthenium metathesis complex via electronic and structural withdrawing of the chelating alkoxy ligand were investigated. By decreasing the donor properties of the oxygen atom, an acceleration in catalytic activity was achieved based on facilitation of the initiation step. Conformational constraints of the chelating ether linkage led to the unexpected disturbance of the complex geometry and a vast improvement of the activity.