Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Protocol
  • Published:

Synthesis of N-heterocyclic carbene ligands and derived ruthenium olefin metathesis catalysts

Abstract

We describe the synthesis of commonly used free N-heterocyclic carbenes (NHCs), 1,3-bis-(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes) and 1,3-bis-(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr), and of the two corresponding ruthenium-based metathesis complexes. The complex containing IMes was found to be highly efficient in macrocyclizations involving ring-closing metatheses (RCM), whereas the complex featuring the IPr ligand shows excellent activity in both RCM and cross metathesis because of its greater stability. The free carbenes IMes and IPr are isolated in four steps, with an overall yield of 50%. They are then used to replace a labile phosphine in precatalysts belonging to two families of ruthenium-containing complexes, benzylidene and indenylidene types, respectively. Such complexes are isolated as analytically pure compounds with 77% and 95% yield. The total time for the synthesis of the free NHCs is 56 h, and incorporation in complexes requires an additional 4–5 h.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: NHC and complexes described in this contribution.
Figure 2: Synthesis of free IMes and IPr.
Figure 3: Synthesis of olefin metathesis complexes.

Similar content being viewed by others

References

  1. Fürstner, A. Olefin metathesis and beyond. Angew. Chem. Int. Ed. 39, 3012–3043 (2000).

    Article  Google Scholar 

  2. Trnka, T.M. & Grubbs, R.H. The development of L2X2Ru=CHR olefin metathesis catalysts: an organometallic success story. Acc. Chem. Res. 34, 18–29 (2001).

    Article  CAS  Google Scholar 

  3. Grubbs, R.H. (ed). In Handbook of Metathesis 1st edn, Vol. 1–3 (Wiley-VCH, 2003).

  4. Astruc, D. The metathesis reactions: from a historical perspective to recent developments. New J. Chem. 29, 42–56 (2005).

    Article  CAS  Google Scholar 

  5. Deshmukh, P.H. & Blechert, S. Alkene metathesis: the search for better catalysts. Dalton Trans. 2007, 2479–2491 (2007).

    Article  Google Scholar 

  6. Hoveyda, A.H. & Zhugralin, A.R. The remarkable metal-catalysed olefin metathesis reaction. Nature 450, 243–251 (2007).

    Article  CAS  Google Scholar 

  7. Deiters, A. & Martin, S.F. Synthesis of oxygen- and nitrogen-containing heterocycles by ring-closing metathesis. Chem. Rev. 104, 2199–2238 (2004).

    Article  CAS  Google Scholar 

  8. McReynolds, M.D., Dougherty, J.M. & Hanson, P.R. Synthesis of phosphorus and sulfur heterocycles via ring-closing olefin metathesis. Chem. Rev. 104, 2239–2258 (2004).

    Article  CAS  Google Scholar 

  9. Donohoe, T.J., Orr, A.J. & Bingham, M. Ring-closing metathesis as a basis for the construction of aromatic compounds. Angew. Chem. Int. Ed. 45, 2664–2670 (2006).

    Article  CAS  Google Scholar 

  10. Nicolaou, K.C., Bulger, P.G. & Sarlah, D. Metathesis reactions in total synthesis. Angew. Chem. Int. Ed. 44, 4490–4527 (2005).

    Article  CAS  Google Scholar 

  11. Gradillas, A. & Pérez-Castells, J. Macrocyclization by ring-closing metathesis in the total synthesis of natural products: reaction conditions and limitations. Angew. Chem. Int. Ed. 45, 6086–6101 (2006).

    Article  CAS  Google Scholar 

  12. Magauer, T., Martin, H.J. & Mulzer, J. Ring-closing metathesis and photo-Fries reaction for the construction of the ansamycin antibiotic kendomycin: development of a protecting group free oxidative endgame. Chem. Eur. J. 16, 507–519 (2010).

    Article  CAS  Google Scholar 

  13. Van de Weghe, P., Bisseret, P., Blanchard, N. & Eustache, J. Metathesis of heteroatom-substituted olefins and alkynes: current scope and limitations. J. Organomet. Chem. 691, 5078–5108 (2006).

    Article  CAS  Google Scholar 

  14. Compain, P. Olefin metathesis of amine-containing systems: beyond the current consensus. Adv. Synth. Catal. 349, 1829–1846 (2007).

    Article  CAS  Google Scholar 

  15. Kotha, S. & Lahiri, K. Synthesis of diverse polycyclic compounds via catalytic metathesis. Synlett 39, 2767–2784 (2007).

    Article  Google Scholar 

  16. Nguyen, S.T., Johnson, L.K., Grubbs, R.H. & Ziller, J.W. Ring-opening metathesis polymerization (ROMP) of norbornene by a group VIII carbene complex in protic media. J. Am. Chem. Soc. 114, 3974–3975 (1992).

    Article  CAS  Google Scholar 

  17. Schwab, P., France, M.B., Ziller, J.W. & Grubbs, R.H. A series of well-defined metathesis catalysts - synthesis of [RuCl2(=CHR′)(PR3)2] and its reactions. Angew. Chem. Int. Ed. Engl. 34, 2039–2041 (1995).

    Article  CAS  Google Scholar 

  18. Huang, J., Stevens, E.D., Nolan, S.P. & Petersen, J.L. Olefin metathesis-active ruthenium complexes bearing a nucleophilic carbene ligand. J. Am. Chem. Soc. 121, 2674–2678 (1999).

    Article  CAS  Google Scholar 

  19. Scholl, M., Ding, S., Lee, C.W. & Grubbs, R.H. Synthesis and activity of a new generation of ruthenium-based olefin metathesis catalysts coordinated with 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene ligands. Org. Lett. 1, 953–956 (1999).

    Article  CAS  Google Scholar 

  20. Achermann, L., Fürstner, A., Weskamp, T., Kohl, F.J. & Hermann, W.A. Ruthenium carbene complexes with imidazolin-2-ylidene ligands allow the formation of tetrasubstituted cycloalkenes by RCM. Tetrahedron Lett. 40, 4787–4790 (1999).

    Article  Google Scholar 

  21. Samojlowicz, C., Bieniek, M. & Grela, K. Ruthenium-based olefin metathesis catalysts bearing N-heterocyclic carbene ligands. Chem. Rev. 109, 3708–3742 (2009).

    Article  CAS  Google Scholar 

  22. Vougioukalakis, G.C. & Grubbs, R.H. Ruthenium-based heterocyclic carbene-coordinated olefin metathesis catalysts. Chem. Rev. 110, 1746–1787 (2010).

    Article  CAS  Google Scholar 

  23. Dragutan, V., Dragutan, I. & Verpoort, F. Ruthenium indenylidene complexes. Platinum Metals Rev. 49, 33–40 (2005).

    Article  CAS  Google Scholar 

  24. Boeda, F., Clavier, H. & Nolan, S.P. Ruthenium-indenylidene complexes: powerful tools for metathesis transformations. Chem. Commun. 24, 2726–2740 (2008).

    Article  Google Scholar 

  25. Fürstner, A., Thiel, O.R., Ackermann, L., Schanz, H.-J. & Nolan, S.P. Ruthenium carbene complexes with N,N-bis(mesityl)imidazol-2-ylidene ligands: RCM catalysts of extended scope. J. Org. Chem. 65, 2204–2207 (2000).

    Article  Google Scholar 

  26. Jafarpour, L., Stevens, E.D. & Nolan, S.P. A sterically demanding nucleophilic carbene: 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene). Thermochemistry and catalytic application in olefin metathesis. J. Organomet. Chem. 606, 49–54 (2000).

    Article  CAS  Google Scholar 

  27. Nolan, S.P. Synthesis of 1,3 distributed imidazolium salts. US Patent 7,109,348 (2006).

  28. Arduengo, A.J. Preparation of 1,3 disubstituted imidazolium salts. US Patent 5,077,414 (1991).

  29. Arduengo, A.J., Krafczyk, R., Schmutzler, R., Craig, H.A., Goerlich, J.R., Marshall, W.J. & Unverzagt, M. Imidazolylidenes, imidazolinylidenes and imidazolidines. Tetrahedron 55, 14523–14534 (1999).

    Article  CAS  Google Scholar 

  30. Arduengo, A.J., Dias, R., Harlow, R.L. & Kline, M. Electronic stabilization of nucleophilic carbenes. J. Am. Chem. Soc. 114, 5530–5534 (1992).

    Article  CAS  Google Scholar 

  31. Nolan, S.P. & Huang, J. Catalyst complex with carbene ligands. US Patent 7,622,590 (2009).

  32. Laleh Jafarpour, L., Schanz, H.-J., Stevens, E.D. & Nolan, S.P. Indenylidene-imidazolylidene complexes of ruthenium as ring-closing metathesis catalysts. Organometallics 18, 5416–5419 (1999).

    Article  Google Scholar 

  33. Boeda, F., Bantreil, X., Clavier, H. & Nolan, S.P. Ruthenium-indenylidene complexes: scope in cross-metathesis transformations. Adv. Synth. Catal. 350, 2959–2966 (2008).

    Article  CAS  Google Scholar 

  34. Grubbs, R.H., Schwab, P. & Nguyen, S.T. High metathesis activity ruthenium and osmium metal carbene complexes. US Patent 7,102,047 (2006).

  35. Harlow, K.J., Hill, A.F. & Wilton-Ely, J.D.E.T. The first co-ordinatively unsaturated Group 8 allenylidene complexes: insights into Grubbs' vs. Dixneuf–Fürstner olefin metathesis catalysts. Dalton Trans. 1999, 285–291 (1999).

    Article  Google Scholar 

  36. Shaffer, E.A., Chen, C.-L., Beatty, A.M., Valente, E.J. & Schanz, H.-J. Synthesis of ruthenium phenylindenylidene, carbyne, allenylidene and vinylmethylidene complexes from (PPh3)3–4RuCl2: a mechanistic and structural investigation. J. Organomet. Chem. 692, 5221–5233 (2007).

    Article  CAS  Google Scholar 

  37. Quideau, S., Looney, M.A. & Pouységu, L. Oxidized arenol intermediates in intermolecular carbon-carbon bond formation. Naphthoid cyclohexa-2,4-dienones via oxidative nucleophilic substitution. Org. Lett. 1, 1651–1654 (1999).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We are grateful to the European Community for funding through the seventh framework program (CP-FP 211468–2-EUMET).

Author information

Authors and Affiliations

Authors

Contributions

X.B. carried out experimental procedure development, synthetic work and assembly of the manuscript; S.P.N. performed ligand synthesis and manuscript assembly.

Corresponding author

Correspondence to Steven P Nolan.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Bantreil, X., Nolan, S. Synthesis of N-heterocyclic carbene ligands and derived ruthenium olefin metathesis catalysts. Nat Protoc 6, 69–77 (2011). https://doi.org/10.1038/nprot.2010.177

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nprot.2010.177

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing