A Hydrazone Ligand for Iridium-Catalyzed C-H Borylation: Enhanced Reactivity and Selectivity for Fluorinated Arenes.

Ir-catalyzed C-H borylations of fluorinated and cyanated arenes with high -to-F/CN are described. Use of a dipyridyl hydrazone framework as the ancillary ligand and pinacolborane (HBpin) as the functionalizing reagent generates catalysts that are significantly more active selective than 4,4'-di--butyl-2,2'-bipyridine (dtbpy) for both electron-deficient and electron-rich substrates. Investigation of the ligand framework resulted in the observation of formal -borylation of the hydrazone by HBpin, as evidenced by NMR spectroscopy and X-ray crystallography.