Nickel-Catalyzed Regioselectivity-Switchable Hydroheteroarylation of Vinylarenes with Electron-Rich Heteroarenes.

We report the first example of a regioselectivity switch in the hydroheteroarylation of vinylarenes with electron-rich heteroarenes, including benzofurans, benzothiophenes, and indoles, using an expedient ligand-controlled strategy. In the presence of NaO t Bu, Ni(IMes Me )[P(OEt) 3 ]Br 2 yields C2-alkylated heteroarenes with high branched selectivity, whereas the use of Ni(IPr *OMe )[P(OEt) 3 ]Br 2 favors the formation of the corresponding linear products. This robust method also provides easy access to a range of C2-alkylated electron-rich heteroarenes without employing directing groups.