Ligand-Controlled Regioreversed 1,2-Aryl-Aminoalkylation of Alkenes Enabled by Photoredox/Nickel Catalysis

A ligand-controlled regioreversed 1,2-arylalkylation of alkenes via photoredox/nickel dual catalysis is reported. In contrast with previous reports on photoredox/nickel-catalyzed 1,2-alkylarylation reactions that initiate from the Giese addition of an alkyl radical to alkene, this three-component conjugate coupling process occurs through nickel-catalyzed aryl radical addition to alkene, thereby leading to a complementary regioselectivity to conventional 1,2-alkylarylation. An ortho-substituted bipyridyl ligand is the key to tune the regioselectivity, which was found to be dictated by the reactivity of alkene-coordinated LnNi(0) complexes that trigger the formation of aryl radicals via halogen-atom transfer (XAT). This regioreversed transformation allows a concise entry to structurally abundant β-amino acid derivatives, including ORL1-receptor antagonists.