Electrode-switchable: exploring this new strategy to achieve regiodivergent azidoiodination of alkenes

Abstract

The deployment of electrochemical strategies to achieve chemoselective and stereoselective syntheses has established new avenues for the construction of isomers with distinctive structural frameworks. While these advances are noteworthy, the capacity of these strategies to endow regioselectivity remains insufficiently explored. Herein, we introduce an “electrode-switchable” strategy that orchestrates the electrode-mediated regioselective azidoiodination of alkenes, showcasing the controlled diversification potential of this approach. This strategy was influenced by the choice of anode electrode materials to selectively generate different oxidation states of iodine species starting from I⁻. Utilizing a graphite plate anode leads to α-azido iodo compounds following the azidoiodination of alkenes. In contrast, employing a Pt plate anode reverses this regioselectivity, yielding β-azido iodo compounds. Insights gleaned from density functional theory calculations and cyclic voltammetry electrochemical tests suggest that the adsorption energy of I⁻ on the Pt electrode surface and its highest oxidation state are significantly higher than those on graphite. This difference elucidates why, relative to graphite, a greater proportion of I⁻ ions undergo oxidation on Pt, resulting in more pronounced electron loss and higher oxidation states. Additional mechanistic investigations, including control experiments, corroborate this interpretation and highlight the anode material's pivotal influence on the regiodivergent selectivity observed in the azidoiodination of alkenes.