Electrochemical Reductive β‐Arylation and Alkenylation of α‐Branched Acroleins by Primary Amine/Nickel Dual Catalysis

ABSTRACT For nearly 2 decades, radical reactivity based on aminocatalysis has predominantly relied on the single‐electron oxidation of enamines to access α‐imino radical cations, enabling versatile α‐functionalization. Herein, we report a divergent reductive catalytic paradigm that leverages electrochemistry to achieve the direct single‐electron reduction of electron‐deficient iminium ions. This approach provides mild and streamlined access to β‐enaminyl radicals, bypassing the conventional requirements for enamine oxidation/deprotonation or iminium photoexcitation. Crucially, this reductive platform is successfully integrated into a dual nickel/amine catalytic cycle. By intercepting the transient β‐enaminyl radical with a nickel center, we achieved the direct β‐arylation and alkenylation of enals—substrates that are typically incompatible with traditional reductive cross‐coupling, with aryl or alkenyl halides affording high productivity and good chemoselectivity. This work not only expands the synthetic utility of aminocatalytic intermediates through electrochemical tuning but also establishes a robust framework for merging organocatalytic radical generation with transition‐metal‐catalyzed cross‐coupling reactions.