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.