Selective electrophilic monofluorination on rings of various sizes using elemental fluorine

Elemental fluorine substitutes tertiary unactivated hydrogens in an electrophilic mode. This unorthodox substitution depends on the atomic charge density, on the hydrogen atom and on the p-orbital contribution on the CH bond. This is demonstrated by reacting F₂ with tertiary CH bonds located on rings of various sizes, producing the corresponding tertiary fluorine derivatives.