Iron Catalyzed Double Bond Isomerization: Evidence for an Fe<sup>I</sup>/Fe<sup>III</sup> Catalytic Cycle
Callum R. Woof, Derek J. Durand, Natalie Fey, Emma Richards, Ruth L. Webster
Abstract
Abstract Iron‐catalyzed isomerization of alkenes is reported using an iron(II) β‐diketiminate pre‐catalyst. The reaction proceeds with a catalytic amount of a hydride source, such as pinacol borane (HBpin) or ammonia borane (H 3 N⋅BH 3 ). Reactivity with both allyl arenes and aliphatic alkenes has been studied. The catalytic mechanism was investigated by a variety of means, including deuteration studies, Density Functional Theory (DFT) and Electron Paramagnetic Resonance (EPR) spectroscopy. The data obtained support a pre‐catalyst activation step that gives access to an η 2 ‐coordinated alkene Fe I complex, followed by oxidative addition of the alkene to give an Fe III intermediate, which then undergoes reductive elimination to allow release of the isomerization product.