Electrochemical Hydrogenation of Arenes and Heteroarenes: Tuning Partial and Full Reduction

Electrochemical hydrogenation is emerging as a powerful strategy to reduce arenes and heteroarenes under mild conditions without relying on external H 2 gas. This review highlights recent advances in partial and full electrochemical hydrogenation of aromatic compounds, with emphasis on how electrochemical parameters control the extent of reduction. Partial hydrogenation and Birch-type electroreduction use waveform control, cathode-interface design, reaction-medium effects and trapping strategies to interrupt reduction before overhydrogenation. In parallel, full hydrogenation has advanced rapidly for N-heteroarenes, where water-derived hydrogen, catalyst design and reactor configuration enable direct access to saturated heterocycles. Recent examples further show how electrochemical hydrogenation can be extended to reductive deuteration, dearomative functionalization and asymmetric tandem reactions. Together, these studies show that electrochemical hydrogenation is not simply a replacement for high-pressure catalytic hydrogenation, but a tunable platform in which electron delivery, surface-hydrogen generation, adsorption and mass transport can be adjusted to access either partially or fully hydrogenated products.