Exploiting a Difference in Leaving Group Ability: An Approach to β‑Substituted Monofluoroalkenes Using <i>gem</i>-Chlorofluoropropenes

The superior nucleofuge character of chlorine over fluorine was taken advantage of in the selective SN2′ substitution reaction of gem-chlorofluoropropenes, allowing for the clean formation of β-substituted monofluoroalkenes under metal-free conditions. Numerous N-, S-, O-, and C-nucleophiles behaved nicely in this system. Further synthetic transformations of selected monofluoroalkenes were also accomplished.