Deprotonation of fluoro aromatics using lithium magnesates

3-Fluoropyridine was deprotonated on treatment with 1/3 equiv of Bu3MgLi in THF at −10 °C. The lithium arylmagnesate formed was either trapped with electrophiles or involved in a palladium-catalyzed cross-coupling reaction with 2-bromopyridine. The use of a less nucleophilic lithium-magnesium-dialkylamide, (TMP)3MgLi, allowed the reaction of 3-fluoroquinoline, giving the 2,2′-dimeric derivative. 2-Fluoropyridine and 2,6-difluoropyridine were deprotonated using 1/3 equiv of the highly coordinated magnesate Bu4MgLi2 in THF at −10 °C in the presence of a substoichiometric amount of 2,2,6,6-tetramethylpiperidine. 1,3-Difluorobenzene reacted similarly when treated with Bu3MgLi; the reactivity of the base proved to be enhanced by the presence of TMEDA.