Diels–Alder reactions in ionic liquids . A safe recyclable alternative to lithium perchlorate–diethyl ether mixtures

(Note: The full text of this document is currently only available in the PDF Version )

Martyn J. Earle, Paul B. McCormac and Kenneth R. Seddon

Diels–Alder reactions in neutral ionic liquids (such as 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium tetrafluoroborate, and 1-butyl-3-methyl-imidazolium lactate) are reported. Rate enhancements and selectivities similar to those of reactions performed in lithium perchlorate–diethyl ether mixtures have been observed. As the ionic liquids used have no measurable vapour pressure, are thermally robust, will tolerate impurities such as water, and are recyclable, it is envisaged that these systems could be used on an industrial scale.


  1. J. Sauer and R. Sustmann, Angew. Chem., Int. Ed. Engl., 1980, 19, 779 CrossRef.
  2. G. J. Griffiths and F. E. Previdoli, J. Org. Chem., 1993, 58, 6129 CrossRef CAS.
  3. D. C. Rideout and R. J. Breslow, J. Am. Chem. Soc., 1980, 102, 7816 CrossRef CAS.
  4. M. J. Diego-Castro and H. C. Hailes, Tetrahedron Lett., 1998, 39, 2211 CrossRef CAS.
  5. R. Van Eldik, T. Asano and W. J. Le Noble, Chem. Rev., 1989, 89, 589.
  6. S. T. Handy, P. A. Grieco, C. Mineur and L. Ghosez, Synlett, 1995, 565 CrossRef CAS.
  7. D. A. Jaeger and C. E. Tucker, Tetrahedron Lett., 1995, 30, 1785 CrossRef CAS.
  8. J. K. M. Sanders and C. J. Walter, Angew. Chem., Int. Ed. Engl., 1995, 34, 217 CrossRef CAS.
  9. Z. Clyde-Watson, A. Vidal-Ferran, L. J. Twyman, C. J. Walter, D. W. J. McCallien, S. Fanni, N. Bampos, R. S. Wylie and J. K. M. Sanders, New J. Chem., 1998, 22, 493 RSC; M. Marty, Z. Clyde-Watson, L. J. Twyman, M. Nakash and J. K. M. Sanders, Chem. Commun., 1998, 2265 RSC.
  10. P. A. Grieco, J. J. Nunes and M. D. Gaul, J. Am. Chem. Soc., 1990, 112, 4595 CrossRef CAS.
  11. A. Kumar, J. Org. Chem., 1994, 59, 4612 CrossRef CAS.
  12. M. A. Forman and W. P. Dailey, J. Am. Chem. Soc., 1991, 113, 2761 CrossRef CAS.
  13. C. J. Adams, M. J. Earle, G. Roberts and K. R. Seddon, Chem. Commun., 1998, 2097 RSC.
  14. Y. L. Chauvin, L. Mussmann and H. Olivier, Angew. Chem., Int. Ed. Engl., 1996, 34, 2698 CrossRef.
  15. P. A. Z. Suarez, J. E. L. Dullius, S. Einloft, R. F. de Souza and J. Dupont, Polyhedron, 1996, 15, 1217 CrossRef CAS.
  16. N. Papageorgiou, Y. Athanassov, M. Armand, P. Bônhote, H. Pettersson, A. Azam and M. Grätzel, J. Electrochem. Soc., 1996, 10, 3099.
  17. C. M. Gordon, J. D. Holbrey, A. R. Kennedy and K. R. Seddon, J. Mater. Chem., 1998, 8, 2627 RSC.
  18. J. D. Holbrey and K. R. Seddon, J. Chem. Soc., Dalton Trans., 1998, in press Search PubMed.