The cyclopentadienyl ligand is an important ligand in organometallic chemistry because it will complex a wide range of transition metals.[1] Recently there has been an increased attention to cyclopentadiene ligands containing pendant groups that are capable of coordinating to a metal centre as well. Examples of these bidentate ligands are cyclopentadiene ligands containing amine[2,3], ether[4], amido[5,6] and alkoxy [7] pendant groups.

The asymmetric catalytic properties of cyclopentadiene metal complexes are also receiving more attention. Different strategies have been developed to introduce asymmetry in cyclopentadiene metal complexes.[8] Examples of these strategies are the use of cyclopentadiene ligands with a chiral substituent connected to the cyclopentadiene ring [9], the use of annulated chiral cyclopentadiene ligands [1,10] and the use of ansa-bridged bis-indenyl ligands in which the group bridging the two indenyls is either achiral [11] or chiral.[12] Chiral cyclopentadiene ligands containing a pendant donor have been described in only a few papers.[4,13] Recently the synthesis of a chiral cyclopentadiene ligand based on ephedrine and pseudo ephedrine was described.[14]

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  1. Okuda, J. Topics in Current Chemistry, 1991, 160, 97
  2. Wang, T.-F.; Wen, Y.-S. J. Organomet. Chem. 1992, 439, 155.
  3. Wang, T.-F.; Lee, T.-Y. J. Organomet. Chem. 1992, 423, 31.
  4. Huang, Q.; Yanlong, Q. Synthesis, 1987, 910.
  5. Hughes, K. H.; Meetsma, A.; Teuben, J. H. Organometallics, 1993, 12, 1936.
  6. Wang, T.-F.; Lee, T.-Y.; Wen, Y.-S.; Liu, L.-K. J. Organomet. Chem. 1991, 403, 353.
  7. Rieger, B.; Steimann, M.; Fawzi, R. Chem. Ber. 1992, 125, 2373.
  8. Halterman, R. L. Chem. Rev. 1992, 92, 965.
  9. Cesarotti, E.; Kagan, H. B. J. Organomet. Chem. 1978, 162, 297.
  10. Colletti, S. L.; Halterman, R. L. Tetrahedron Lett. 1989, 30, 3513.
  11. Wild, F. R. W. P.; Zsolnai, L.; Huttner, G.; Brintzinger, H. H. J. Organomet. Chem. 1982, 232, 233.
  12. Burk, M. J.; Colletti, S. L.; Halterman, R. L. Organometallics, 1991, 10, 2998.
  13. Adams, H.; Bailey, N. A.; Colley, M.; Schofield, P. A.; White, C. J. Chem. Soc. , Dalton Trans. 1994, 1445.
  14. vanderZeijden, A. H. H. Tetrahedron: Asymmetry, 1995, 6, 913.