Electroreductive Nickel Catalysis Enabled Giese Hydroalkylation of Unactivated Tertiary Alkyl Bromides.

We report a nickel-catalyzed electroreductive Giese hydroalkylation of unactivated tertiary alkyl bromides with electron-deficient alkenes. The transformation proceeds under mild, constant-current conditions in a simple undivided cell, employing an iron sacrificial anode and an accessible nickel/bipyridine catalyst system. This protocol features broad substrate scope, excellent functional-group tolerance, and high efficiency, enabling the late-stage modification of structurally complex molecules and pharmaceuticals. Mechanistic investigations-including cyclic voltammetry and deuterium-labeling experiments-indicate that the reaction operates through a Ni(I)/Ni(II) redox cycle that mediates single-electron activation of tertiary alkyl bromides. The resulting alkyl radicals undergo conjugate addition to electron-deficient alkenes, followed by cathodic reduction and protonation to furnish the hydroalkylation products.