Pseudohalide‐Guided Redox Control Enables Electrochemical Auto‐Tandem Nickel Catalysis for Butafulvene Synthesis.

Abstract Electrochemical nickel catalysis offers a unique platform for redox‐controlled reactivity, yet its application to tandem catalysis remains underexplored. We report the development, mechanistic elucidation, and synthetic application of a conceptually novel electrochemical strategy that enables auto‐tandem nickel‐catalyzed (e‐ATC) conversion of propargyl carbonates into butafulvenes, highly strained, antiaromatic scaffolds with limited synthetic accessibility. Comprehensive mechanistic investigations reveal that this transformation merges a reductive coupling with a mechanistically distinct cycloisomerization, both mediated by a single nickel catalyst under electroreductive conditions. Crucially, pseudohalide ligands play a central role in steering a controlled Ni(0)/Ni(II) redox manifold by suppressing one‐electron Ni(I) pathways, thereby favoring a polar two‐electron mechanism. The method enables broad access to butafulvenes, including fused‐ring variants that are inaccessible by previous catalytic routes. Further derivatizations demonstrate the synthetic utility of these butafulvenes as precursors to strained dendralenes and complex polycyclic frameworks.