Unsaturated Carboxylates as Electrophilic Synthons for Transition-Metal-Catalyst-Free Electroreductive Deoxygenative Coupling.

The use of ester-derived electrophiles in transition-metal-free electroreductive C(sp3)─C(sp3) bond formation remains largely unexplored. Herein, we report a sacrificial-anode-enabled electroreductive cross-coupling of simple unsaturated carboxylates with unactivated alkyl halides. Aryl, alkenyl, and alkynyl carboxylates are readily incorporated, affording methylene-bridged alkylarenes together with allylic and propargylic C(sp3)-rich frameworks under mild conditions. Mechanistic studies support independent single-electron reduction of both electrophilic partners, followed by radical-radical coupling, alkoxide elimination, and cathodic deoxygenation via a Clemmensen-like reduction pathway. This work establishes unsaturated carboxylates as a new class of alkylating reagents for electroreductive C(sp3)─C(sp3) bond formation.