Cobalt-Catalyzed C(sp)-C(sp) Suzuki-Miyaura Cross Coupling.

A cobalt-catalyzed method for the C(sp)-C(sp) Suzuki-Miyaura cross coupling of aryl boronic esters and alkyl bromides is described. Cobalt-ligand combinations were assayed with high-throughput experimentation, and cobalt(II) sources with -,'-dimethylcyclohexane-1,2-diamine (DMCyDA, L) produced optimal yield and selectivity. The scope of this transformation encompassed steric and electronic diversity on the aryl boronate nucleophile as well as various levels of branching and synthetically valuable functionality on the electrophile. Radical trap experiments support the formation of electrophile-derived radicals during catalysis.