Divergent rearrangements of cyclopropyl-substituted fluoroepoxides involving C-F bond cleavage and formation

Org Lett. 2014 Feb 7;16(3):888-91. doi: 10.1021/ol403644n. Epub 2014 Jan 14.

Abstract

Unprecedented divergent rearrangements of cyclopropyl-substituted fluoroepoxides are reported. In the presence of a catalytic amount of benzoic acid, cyclopropyl-substituted fluoroepoxides efficiently undergo 1,5-fluorine migration. However, when the fluoroepoxides are heated with K2CO3 at 60 °C, 1,2-fluorine migration occurs. The 1,5-fluorine migration is believed to proceed via a carbocation intermediate, while the 1,2-fluorine migration may involve a tight ion pair intermediate or proceed via a concerted process.