Chiral Bioinspired Non‐Heme Iron Complexes for Enantioselective Epoxidation of α,β‐Unsaturated Ketones

Chiral bioinspired iron complexes of N₄ ligands based on the ethylenediamine backbone display remarkable levels of enantioselectivity for the first time in the asymmetric epoxidation of α,β‐unsaturated ketones using hydrogen peroxide (up to 87% ee) or peracetic acid as oxidant, respectively. Notablely, isotopic labeling with H₂¹⁸O strongly demonstrated that there is a reversible water binding step prior to generation of the significant intermediate. Besides, the complex L₂Fe(III)₂(μ‐O)(μ‐CH₃CO₂)]³⁺ usually derived from the decay of the LFe(IV)O species or thermodynamic sinks for a number of iron complexes was identified by HR‐MS. In addition, the possible mechanisms were proposed and LFe(V)O species may be the main active intermediate in the catalytic system.