Nickel-Catalyzed C(sp2)–H Borylation of Arenes

In this study, C­(sp2)–H borylation of arenes was accomplished by a nickel catalyst, resulting in good yield. Alkyl and alkoxy arenes were successfully functionalized, affording C­(sp2)–H borylated compounds. It was unraveled that the well-defined abnormal N-heterocyclic carbene based Ni­(II) complex breaks into Ni nanoparticles (Ni-NPs), which act as catalytically active species. A series of controlled reactions under stoichiometric conditions along with spectroscopic studies and single-crystal X-ray crystallographic study helped us to understand the formation of Ni-NPs along with formation of a boron­(III) compound during this reaction.