Synthesis of gem-Difluoromethylene Containing Cycloalkenes via the Ring-Opening Reaction of gem-Difluorocyclopropanes and Subsequent RCM Reaction.

The radical-type ring-opening reaction of gem-difluorocyclopropanes and subsequent regioselective monoepoxidation of the products were demonstrated. Introduction of a vinyl or allyl group to the epoxide produced the diene derivatives that were subjected to the ring closing metathesis reaction to furnish the gem-difluoromethylene containing cyclopentene, cycloheptene, and cyclooctene derivatives in good to excellent yields.