β-Scission by Direct Electrochemical Oxidation: Proton-coupled Electron Transfer Mechanism Dictated by Synthetic Study and Computations

Abstract

β-Scission from alkoxy radical enables selective Csp3-Csp3 bond cleavage under ambient conditions, offering a useful method for organic synthesis. Various photocatalytic systems for β-scission have been reported, where proton-coupled electron transfer (PCET) mechanism plays a key role in the generation of alkoxy radical and thus β-scission. Electrochemical β-scission has been mainly pioneered in the presence of mediator, and a direct electrochemical system has rarely been investigated. Here, we investigated the βscission via direct electrochemical oxidation using a model compound with β-O-4 linkage.Synthetic experiments suggested smooth progress of β-scission in the presence of collidine as a base. Cyclic voltammetry measurement, voltammetric simulation, and quantum simulation suggested the PCET mechanism is responsible for the electrochemical reaction, which is followed by -scission process. This report provides fundamental insights into the electrochemical -scission via direct electron transfer on the electrode, which contribute to future applications such as biomass valorization.

Additive-controlled chemoselective inter-/intramolecular hydroamination via electrochemical PCET process

“…A decrease in the oxidation current can be considered as a decrease in the diffusion coefficient of the hydrogen bond complex; thus, we attempted to reproduce the CV pattern by computational simulation (Figures S1 and S2 in Supporting Information File 1 ) [ 16 ]. The results indicated that an excessively small diffusion coefficient (1/10- or 1/100-fold) is required to reproduce a CV pattern similar to that observed experimentally.…”