Palladium-Catalyzed Directed Halogenation of Bipyridine <i>N</i>‑Oxides ZuckerSina P. WossidloFriedrich WeberManuela LentzDieter TzschuckeC. Christoph 2017 The palladium-catalyzed directed C–H halogenation of bipyridine <i>N</i>-oxides was investigated. Using NCS or NBS (<i>N</i>-chloro- or <i>N</i>-bromosuccinimide) and 5 mol % Pd­(OAc)<sub>2</sub> in chlorobenzene (0.10 molar) at 110 °C, pyridine-directed functionalization took place and 3-chloro- or 3-bromobipyridine <i>N</i>-oxides were obtained in high yields. The reaction is sensitive to steric hindrance by 4- and 6′-substituents. Only in the latter case, where coordination of palladium by the pyridine is hindered, 3′-halogenation directed by the <i>N</i>-oxide function was observed. The halogenated products were deoxygenated by PCl<sub>3</sub> or PBr<sub>3</sub>.