π-Interaction-Guided Tuning of Ferrocene Redox Mediators for Shono-Type Allylation of N-Aryl Amines
Year: 2026
Type: preprint
Abstract: The development of Shono-type oxidation reactions for late-stage functionalization has recently focused on the expansion of compatible nucleophiles; however, a central limitation is N-aryl, or aniline-derived, substrates due to oxidative sensitivity that leads to decomposition under direct electrolysis. Redox mediators have recently been employed to drive Shono-type oxidation reactions at lower overpotentials but are underdeveloped with aniline-type substrates. We demonstrate that electron-transfer (ET)-based ferrocene (Fc) mediators are capable of driving a rare Shono-type allylation reaction using simple allyl trifluoroborate salt with a variety of N-aryl substrates. Computational data probing the nature of ET from substrate to Fc+ suggests a distinct π-interaction, leading to our evaluation of phenyl-appended Fc (FcPh) for enhanced reactivity. We find that FcPh improves reaction efficiency across structurally diverse N-aryl substrates under controlled potential electrolysis (CPE) at applied potentials differing only by 20 mV, illustrating a distinct handle for tuning Fc redox mediators via proposed non-covalent interactions. DFT supports a working model for “out-ofcage” and “in-cage” single electron transfer (SET)pathways that provides a rationale for observed trends. In the presence of benzene co-solvent, the advantage of FcPh is suppressed, supporting the proposed role of π-interactions between FcPh and N-aryl substrates. These results highlight mediatorbased π-interactions as a strategy for tuning mediation efficiency without substantial alteration of mediator redox potential.
Source: ChemRxiv
Institutions: Boston University, University of California System
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7212250887