Non-Symmetrical Tetrafluoroalkadienes Synthesized by ROCM of 3,3,4,4-Tetrafluorocyclobutene.

As the first known example of ring-opening cross metathesis (ROCM) of polyfluorinated strained cyclobutenes, ROCM of 3,3,4,4-tetrafluorocyclobutene with electronically rich alkenes, catalyzed by Grubbs or Hoveyda-Grubbs 2nd generation precatalysts, gave a small library of non-symmetrical isolated dienes bearing a tetrafluoroethylene spacer between the double bonds. 1-Butoxy-3,3,4,4-tetrafluorohexa-1,5-diene thus formed underwent subsequent regioselective cross metathesis (CM) with a series of styrenes, catalyzed by Hoveyda-Grubbs 2nd generation precatalyst, leading to non-symmetrically substituted dienes. 6,6-Dibutoxy-3,3,4,4-tetrafluorohex-1-ene, formed by regioselective butoxylation of 1-butoxy-3,3,4,4-tetrafluorohexa-1,5-diene, was dihydroxylated and cyclized to the corresponding 3,3,4,4-tetrafluorohexopyranose.