Recent Catalytic Applications of (Cyclopentadienone)iron Complexes

Abstract

(Cyclopentadienone)iron complexes (CICs) are attractive pre‐catalysts due to their easy preparation and robustness, which are uncommon features in homogeneous iron catalysis. They represent a striking example of how deeply a non‐innocent ligand may affect the catalytic properties of the metal. Swinging between the cyclopentadienone and the hydroxycyclopentadienyl form, the ligand induces iron to engage in H2 heterolytic cleavage and transfer. The latter represents the basis for numerous applications of CICs in redox chemistry (multiple bond reduction, alcohol oxidation) and “hydrogen borrowing” processes (e.g., alcohol amination) that have been reported over the last few years. Moreover, very recently catalytic applications of CICs in different types of reactivity (where again the non‐innocent ligand plays a key role), have appeared in the literature. This minireview summarizes the advancements that have been made in the field of CICs and their catalytic applications in the period 2014–2019.