INTRAMOLECULAR INSERTION OF AN ETA(5)-CYC LOPENTADIENYL RING IN A BIS-ETA(5)-CYCLOPENTADIENYLTITANACYCLOPENTADIENE

The reaction of in situ-generated titanocene ''Cp(2)Ti'' with 2 equiv. of alkynes Me(3)SiC=CR yields a mixture of symmetrically [Cp(2)TiC(Si Me(3))=C(R)C(R)=C(SiM(3))](R=Ph (3), Py (6)) and unsymmetrically C(SiM e(3))=C(R)C(SiMe(3))=C(R)(SiMe(3))=C(R)](R=Ph (4), Py (7)) substituted titanacyclopentadienes. Complex 7 is unstable and rearranges with an intramolecular insertion of one Cp of the titanocene fragment into the unsymmetrically substituted titanacyclopentadiene to produce the dihy droindenyl complex 8, which was characterized by an X-ray structure an alysis.