Anti-Markovnikov Hydroheteroarylation of Unactivated Alkenes with Indoles, Pyrroles, Benzofurans, and Furans Catalyzed by a Nickel–<i>N</i>‑Heterocyclic Carbene System

We report the catalytic addition of C–H bonds at the C2 position of hetero­arenes, including pyrroles, indoles, benzofurans, and furans, to unactivated terminal and internal alkenes. The reaction is catalyzed by a combination of Ni­(COD)2 and a sterically hindered, electron-rich N-hetero­cyclic carbene ligand or its analogous Ni­(NHC)­(arene) complex. The reaction is highly selective for anti-Markovnikov addition to α-olefins, as well as for the formation of linear alkylheteroarenes from internal alkenes. The reaction occurs with substrates containing ketones, esters, amides, boronate esters, silyl ethers, sulfon­amides, acetals, and free amines.