Pentafluorophenyl cyclopentadiene and its Sodium Salt

Checked by KIMBERLY C. JANTUNEN, FELICIA L. TAW, and JAQUELINE L. KIPLINGER  

Pentafluorophenyl-substituted cyclopentadienide anions are useful ligands for transition metals because tbe CgFs substituent is not only bigbly electron withdrawing but also relatively stable.Up to four CsFs substituents may be attached to cyclopentadiene (or up to two to indene ) by one-pot nucleophilic aromatic substitution reactions of cyclopentadienyl or indenyl anions with hexafluoroben-zene. The title diene was also reported as the major organic product of the photolysis of Cp2Ti(CgF5)2.  

Except where noted, the reactions should be eanled out under an inert atmosphere either in a fume hood using a Sehlenk manifold (N2 or Ar) equipped with a bubbler to release hydrogen formed during the reaetions or in a dry box (He or N2). Sodium cyclopentadienide (2.0-3.OM solution in THF, Strem), sodium hydride (60% mineral oil dispersion, Strem), hexafluorobenzene (Aldrich), hydrochloric 

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