Speeding up borylation

C–H Bond Activation Catalytic borylation is the rare reaction that can selectively target stronger over weaker saturated carbon–hydrogen (C–H) bonds. However, the trade-off has been that the reaction is slow and requires high excess of the hydrocarbon. Oeschger et al. now report that the right ligand (2-methylphenanthroline) coordinated to iridium can accelerate the reaction by 50- to 80-fold. This rate enhancement enables selective borylation of primary C–H bonds with the hydrocarbon as limiting reagent. The reaction is also unusually selective for β-C–H bonds in saturated heterocycles. Science , this issue p. [736][1] [1]: /lookup/doi/10.1126/science.aba6146