Cobalt-catalyzed chemoselective alkenylation and alkylation of C(sp3)–H bond in methyl heteroarenes.

[Display omitted] • Homogeneous cobalt complex for acceptorless dehydrogenation (AD) and borrowing hydrogen (BH) processes. • Chemoselective formation of alkenylation and alkylation products starting from methyl heteroarenes and alcohols. • Sustainable, efficient, and atom-economic C–C bond formation. • Synthetic derivatization to medicinally important structures. Chemoselective synthesis allows for the generation of diverse products from identical starting materials, which is a significant strategy to build molecular diversity rapidly. By employing acceptorless dehydrogenation and borrowing hydrogen strategies, we herein report a cobalt-catalyzed chemoselective C(sp3)–H bond functionalization of methyl heteroarenes, the alkenylation and alkylation products are obtained using alcohol as the coupling partner under different reaction conditions. The scopes of both arenes and alcohols, synthetic applications, preliminary mechanistic studies, and a proposed mechanism were presented. [ABSTRACT FROM AUTHOR]