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. Ring‐opening cross metathesis of 3,3,4,4‐tetrafluorocyclobutene with electronically rich alkenes as butyl vinyl ether or electron donor group substituted styrenes gave a library of non‐symmetrically substituted tetrafluorodienes, which could be further transformed by cross metathesis with styrenes to fluorinated internal dienes or by oxidation and cyclization to tetrafluorohexopyranoses.