Linear\nPaired Electrolysis Enables Redox-Neutral (3\n+ 2) Annulation of Benzofuran with Vinyldiazo Compounds

Electrosynthesis\nhas emerged as a versatile and sustainable tool\nin organic chemistry, offering an efficient pathway for the construction\nof complex molecular architectures under mild and environmentally\nbenign conditions. Traditional electrochemical approaches, however,\npredominantly rely on either anodic oxidation or cathodic reduction,\nlimiting their capacity to achieve redox-neutral transformations using\na single electrode. In this work, we introduce a linear paired electrolysis\nstrategy that circumvents these limitations, enabling a redox-neutral\n(3 + 2) annulation of benzofuran with vinyldiazo compounds. This method\nfacilitates the formation of benzofuran-fused tricyclic scaffolds,\nwhich are valuable in synthetic chemistry and medicinal applications.\nThe transformation proceeds through sequential anodic oxidation and\ncathodic reduction, leveraging a radical cation pathway to deliver\npolycyclic compounds with high selectivity. The efficiency and mechanism\nof this process are thoroughly validated using cyclic voltammetry\nand <i>in situ</i> electrochemical mass spectrometry (EC-MS)\nand supported by theoretical calculations, shedding light on the potential\nof redox-neutral electrochemical transformations.