Halogen shuffling in pyridines: Site selective electrophilic substitutions of 2-chloro-6-(trifluoromethyl)pyridine

Article abstract of DOI:10.1016/S0040-4039(98)00028-8

When treated with lithium diisopropylamide in tetrahydrofuran at -85 °C and subsequently with iodine, 2-chloro-6-(trifluoromethyl)pyridine is neatly converted into its 3-iodo derivative. The latter can be quantitatively isomerized to afford 2-chloro-4-iodo-6-(trifluoromethyl)pyridine. Either iodo compound can serve as the starting material for further manipulation in reaction sequences consisting of halogen/metal exchange and electrophilic trapping.