Ni/Photoredox-Catalyzed C(sp3)−C(sp3) Coupling between Aziridines and Acetals as Alcohol-Derived Alkyl Radical Precursors

Aziridines are readily available C(sp3) precursors that afford valuable β-functionalized amines upon ring-opening. In this article, we report a Ni/photoredox methodology for C(sp3)−C(sp3) cross-coupling between aziridines and me-thyl/1⁰/2⁰ aliphatic alcohols activated as benzaldehyde dialkyl acetals. Orthogonal activation modes of each alkyl coupling partner facilitate cross-selectivity in the C(sp3)−C(sp3) bond-forming reaction: the benzaldehyde dialkyl acetal is activated via hydrogen atom abstraction and β-scission via bromine radical (generated in situ from single-electron oxidation of bromide), whereas the aziridine is activated at the Ni center via reduction. We demonstrate that an Ni(II) azametallacycle, conventionally proposed in aziridine cross-coupling, is not an intermediate in the productive cross-coupling. Rather, stoichiometric organometallic and linear free energy relationship (LFER) studies indicate that aziridine activation proceeds via Ni(I) oxidative addition, a previously unexplored elementary step.