Mediator-based π-Interactions Drive Substrate-Dependent Reactivity in Shono-type Allylation

Excited to share our latest preprint on π-interaction-guided tuning of ferrocene redox mediators. ⚡️

Voltage-controlled electrosynthesis can impart high selectivity, but direct electrolysis still depends on the substrate tolerating the applied potential and avoiding deleterious electrode-surface processes such as fouling. Redox mediators can help overcome these limitations by enabling reaction at milder potentials. In Shono-type transformations, ferrocene mediators remain comparatively underexplored beyond conventional electronic tuning, despite their high degree of structural modularity.

We questioned whether mediator performance could be altered through substrate-mediator interactions while largely preserving redox potential. Appending a single phenyl group to ferrocene shifts the potential by only ~20 mV, yet produces strongly substrate-dependent changes in Shono-type allylation of N-aryl amines, including an increase from 29% to 84% yield in one case.

Computational studies, in collaboration with the fantastic Gutierrez group, and solvent-perturbation experiments support a role for π-interactions, suggesting a complementary way to think about redox-mediator design beyond electronic tuning alone. We are excited to share more soon on this strategy as a mode for altering (and controlling) selectivity.

Congrats to Leyla, Siyuan, Lupita, and XiaoAn! Check it out: https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008696/v1