Regioselective Fluorination of Imidazo[1,2-a]pyridines with Selectfluor in Aqueous Condition

A regioselective synthesis of 3-fluorinated imidazo[1,2-a]pyridines using 1-chloromethyl-4-fluoro-1,4-diazoniabi cyclo[2.2.2]octane bis(tetrafluoroborate) (Selectfluor) as the fluorinating reagent in aqueous condition is described. In the presence of DMAP, the reaction mainly gave monofluorinated product via electrophilic fluorinated process in moderate to good yields.