Electroinduced Reductive\nand Dearomative Alkene-Aldehyde\nCoupling

The direct coupling of alkene feedstocks with aldehydes\nrepresents\nan expedient approach to the generation of new and structurally diverse\nC(sp<sup>3</sup>)-hybridized alcohols that are primed for elaboration\ninto privileged architectures. Despite their abundance, current disconnection\nstrategies enabling the direct coupling of carbon–carbon π-bonds\nand aldehydes remain challenging because contemporary methods are\noften limited by substrate or functional group tolerance and compatibility\nin complex molecular environments. Here, we report a coupling between\nsimple alkenes, heteroarenes and unactivated aliphatic aldehydes via\nan electrochemically induced reductive activation of C–C π-bonds.\nThe cornerstone of this approach is the discovery of rapid alternating\npolarity (rAP) electrolysis to access and direct highly reactive radical\nanion intermediates derived from conjugated alkenes and heterocyclic\ncompounds. Our developed catalyst-free protocol enables direct access\nto new and structurally diverse C(sp<sup>3</sup>)-hybridized alcohol\nproducts. This is achieved by the controlled reduction of conjugated\nalkenes and the C2–C3 π-bond in heteroarenes via an unprecedented\nreductive dearomative functionalization for heterocyclic compounds.\nExperimental mechanistic studies demonstrate a kinetically biased\nsingle-electron reduction of C–C π-bonds over aldehydes.\nApplication of rAP enables chemoselective generation of olefinic radical\nanion intermediates and avoids undesired saturative overreduction.\nOverall, this technology provides a versatile approach to the reductive\ncoupling of olefin and heterocycle feedstocks with aliphatic aldehydes,\noffering straightforward access to diverse C(sp<sup>3</sup>)-rich\noxygenated scaffolds.