Functionalized aryl- or heteroarylmagnesium reagents, prepared
from the corresponding bromides or iodides using halogen-magnesium
exchange or direct magnesium insertion in the presence of lithium
chloride, reacted smoothly with N-fluorobenzenesulfonimide,
(PhSO2)2NF, in the mixed solvent (4:1 CH2Cl2-perfluorodecalin)
to give the corresponding aromatic fluorides in moderate to good yields.
arenes - electrophilic substitution - fluorination - Grignard reagents - heteroaromatic compounds