Ligand-enabled NiH-catalyzed migratory hydroamination: Chain walking as a strategy for regiodivergent/regioconvergent remote sp3C-H amination

Abstract

Direct and positionally selective aliphatic C-H functionalization is an attractive means with which to streamline chemical synthesis. With many possible reaction sites, most traditional methods need a polar-directing group nearby to achieve high regio- and chemoselectivity and are often restricted to a single site of functionalization. Here, we report a nondirected, remote sp3C-H amination process with predictable and switchable regioselectivity. This reaction uses a nickel hydride-catalyzed remote relay hydroamination strategy in which an aliphatic amino group is installed at a position far from the original C=C bond present in all unsaturated hydrocarbon substrates. Depending on the choice of ligand, either terminal or benzylic functionalization products can be obtained with excellent levels of regioselectivity. We also show that an alkyl bromide could also be used as an olefin precursor when using Mn0 as a reductant. The utility of this transformation is further highlighted by the regioconvergent migratory hydroamination of isomeric mixtures of olefins forming single isomers of value-added benzylic or linear amines.