Nickel-catalyzed tandem isomerization/anti-Markovnikov hydroarylation of unactivated internal alkenes with heteroarenes†
Abstract
A tandem isomerization/anti-Markovnikov hydroarylation of unactivated internal alkenes with several types of heteroarenes, including benzimidazoles, indoles, benzofurans, and furans, was realized for the first time by using a catalytic system containing a novel NHC-based heteroleptic Ni(II) complex, Ni(IMXy)[P(OEt)3]Br2 [IMXy = 1,3-bis(4-methoxy-2,6-dimethylphenyl)imidazol-2-ylidene], and a base, KOEt. This tandem transformation allows the flexible synthesis of linear C2-alkylheteroarenes from two simple and easily available feedstock chemicals, unactivated internal alkenes and heteroarenes, in a highly regioselective fashion. The practical utility of this protocol is further highlighted by a scaled-up regioconvergent hydroarylation of the alkene mixture into the same linear product with high yield and regioselectivity.