Synthesis of Substituted Tetrafluorocyclobutenes and Their Ring-Opening Metathesis/Ring-Closing Metathesis to Dihydrofurans Bearing a Tetrafluoroethylene Unit

We report the synthesis of a series of pentafluoro- and tetrafluorocyclobutenes containing alkylthio, phenylthio, alkoxy, phenoxy, and benzyloxy groups via reactions of perfluorocyclobutene with S- and O-nucleophiles. Although these substrates do not undergo ring-opening cross-metathesis with terminal alkenes, the synthesis of dihydrofurans bearing a tetrafluoroethylene unit in the side chain was achieved through a one-pot cascade reaction involving ring-opening and subsequent ring-closing metatheses of alkenyloxy tetrafluorocyclobutenes using the Hoveyda–Grubbs second-generation precatalyst.