Triazine-based cobalt pincer complex for regioselective C-H borylation of furans

Selective C-H borylation of heteroarenes is a valuable strategy for accessing organoboron intermediates, with cobalt pincer complexes demonstrating the potential of first-row transition metals as efficient alternatives to precious-metal catalysts. Here, we report the first application of a triazine-based PNP cobalt pincer complex in the α-selective C-H borylation of furans. The catalytic system affords mono- and di-borylated furans under mild conditions and good to excellent yields, delivering twelve borylated products, including four novel compounds and seven not previously accessed via cobalt catalysis. The synthetic utility of the products was showcased through transformations such as Suzuki-Miyaura coupling and Cu2O-mediated homocoupling, as well as by utilizing in-situ generated HBpin. A plausible Co(I)/Co(III) catalytic cycle is proposed, expanding the scope of cobalt-catalyzed C-H functionalization.