Interhalogen monofluorides (XF; X=Cl, Br or I) generated in situ from
hypohalites or N-halosuccinimides and a source of fluoride ion are “sluggish”
electrophiles. XF reagents formed from F2 gas and a halogen source (ie: ClF3, Br2,
I2,) are very reactive electrophiles. This wide range of reactivity allows the
synthetic chemist to carry out reactions on electron-rich or electron-deficient
substrates. Halofluorinations of alkenes, alkynes and electrophilic aromatic
substitution without catalyst are reviewed. Synthesis of geminal difluorides from
hydrazones is also presented.
