An Improved Method for Difluorocyclopropanation of Alkenes

Difluorocyclopropanation of alkenes using fluorinated acetate salts using convential heating is often a slow, inefficient, and energy-intensive process. We report here a modified protocol which enables the rapid (<5 min) preparation of 1,1-difluorocyclopropanes, using microwave irradiation. The new procedure is not only considerably faster than previously reported methods, but it also employs easily removed, low boiling-point solvents and avoids the use of highly toxic or ozone-depleting substances.