SCIENTIFIC BACKGROUND OF THE PROJECT
During the last decade olefin metathesis (see References and links at http://www.cco.ro/catmet/en/scientific.php) has revolutionized organic synthesis and macromolecular chemistry and nowadays is making its way to applications in nanotechnology. Success of metathesis is due to its efficacy, versatility, chemo-, stereo- and/or regioselectivity, but also to “green chemistry” attributes since it affords environment-friendly and energy-saving technological processes. With the advent of water and functional group tolerant initiators, alkene metathesis (in particular RCM, CM and ROMP) has become an unparalleled synthetic tool for easy access to a host of natural products and biologically active compounds [1, 2].
Along with many other research areas, synthesis of resveratrol and of chemically related antioxidant agents benefited from the early introduction of metathesis protocols [3-5] as an advantageous alternative to previously applied strategies based mainly on Heck reactions.
The two research partners involved in this bilateral cooperation project have a long-standing interest in olefin metathesis dating back to the 1980 ‘[6, 7]. Over the years the Liège team has developed an array of readily available mono- and bimetallic ruthenium-arene complexes, stable to air and bearing different ligands [8]; from many of these complexes the metathesis active catalytic species is generated in situ leading to excellent results in ROMP, RCM and CM. Based on common scientific interests and expertise in metathesis, the Belgian and Romanian groups started to collaborate in this field since 2003, as can be seen from the five common publications (2005-2007)[9]. On the other hand, the Liège team had already performed experiments on metathetical pathways in the synthesis of two important naturally occuring stilbenoid antioxidants, resveratrol and piceatannol [4, 10]. Jointly continuing along these lines in the frame of this collaborative project was therefore considered a suitable development, the more so as recently the interest in resveratrol has peaked due to its potential anti-inflammatory and anticancer properties and of the bioactivity of resveratrol fatty alcohols able to modulate neuroinflammation.
References
1. “Metathesis in Natural Product Synthesis”, J. Cossy, S. Arseniyadis, C. Meyer (Eds.), Wiley-VCH, Weinheim, Germany, 2010.
2. K.C. Nicolaou, P.G. Bulger, D. Sarlah, „Metathesis Reactions in Total Synthesis” Angew. Chem. Int. Ed. 44: 4490–4527 (2005).
3. S. Chang, Y. Na, H.J. Shin, E. Choi, L.S. Jeong, “A short and efficient synthetic approach to hydroxy (E)-stilbenoids via solid-phase cross metathesis”, Tetrahedron Lett., 43(41), 7445-7448 (2002).
4. K. Ferre-Filmon, L. Delaude, A. Demonceau, A.F. Noels, “Stereoselective synthesis of (E)-hydroxystilbenoids by ruthenium-catalyzed cross-metathesis”, Eur. J. Org. Chem. (2005), 3319-3325.
5. J. Velder, S. Ritter, J. Lex, H.-G. Schmalz, „A Simple Access to Biologically Important trans-Stilbenes via Ru-Catalyzed Cross Metathesis”, Synthesis 2006, 273-278 .
6. a. A.F.Noels, A. Demonceau, E. Carlier, A.J. Hubert, R.-L. Márquez-Silva, R.A. Sánchez-Delgado, J. Chem. Soc., Chem. Commun. (12), pp. 783-784 (1988); b. A. Demonceau, A.F. Noels, E. Saive, A.J. Hubert, “Ruthenium-catalyzed ring-opening metathesis polymerization of cycloolefins initiated by diazoesters”, J. Mol. Catal. 76, 123-132 (1992).
7. a. V. Dragutan, A.T. Balaban, M. Dimonie, “Olefin Metathesis and Ring-Opening Polymerization of Cycloolefins” (Rom.), Romanian Academy Publishing House, Bucharest, 1981, 245 pp.; b. V. Dragutan, A.T. Balaban, M. Dimonie, “Olefin Metathesis and Ring-Opening Polymerization of Cycloolefins”, John-Wiley & Sons, Chichester, New York, 1985, 544 pp.
8. a. A.W. Stumpf, E. Saive, A. Demonceau, A.F. Noels, J. Chem. Soc., Chem. Commun. 1995, 1127; b. A. Demonceau, A.W. Stumpf, E. Saive, A.F. Noels, Macromolecules 1997, 30, 3127; c. L. Delaude, A. Demonceau, A.F. Noels, Chem. Commun. 2001, 986 ; d. L. Delaude, M. Szypa, A. Demonceau, A.F. Noels, Adv. Synth. Catal. 2002, 344, 749 ; e. X. Sauvage, Y. Borguet, A.F. Noels, L. Delaude, A. Demonceau, Adv. Synth. Catal. 2007, 349, 255 ; f. X. Sauvage, Y. Borguet, G. Zaragoza, A. Demonceau, L. Delaude Adv. Synth. Catal. 2009, 351, 441-455 ; g. X. Sauvage, A. Demonceau, L. Delaude, Adv. Synth. Catal. 2009, 351, 2031-2038 ; h. L. Delaude, X. Sauvage, A. Demonceau, J. Wouters, Organometallics 2009, 28, 4056–4064; i. X. Sauvage, G. Zaragoza, A. Demonceau, L. Delaude, Adv. Synth. Catal. 2010, 352, 1934-1948.
9. a. I. Dragutan, V. Dragutan, L. Delaude, A. Demonceau, “N-Heterocyclic Carbenes as Highly Efficient Ancillary Ligands in Homogeneous and Immobilized Metathesis Ruthenium Catalytic Systems”, ARKIVOC 2005 (x), p. 206-253; b. V. Dragutan, I. Dragutan, A. Demonceau, “Ruthenium Complexes Bearing N-Heterocyclic Carbene (NHC) Ligands: Highly Efficient Metathesis Pre-catalysts with Enhanced Activity and Selectivity”, Platinum Metals Rev. 2005, 49 (3), 123-137; c. V. Dragutan, I. Dragutan, A. Demonceau, “Recent Developments on Ruthenium Complexes Bearing N-Heterocyclic Carbene (NHC) Ligands as Highly Efficient Metathesis Pre-catalysts”, Platinum Metals Rev. 2005, 49 (4), p. 183-188; d. I. Dragutan, V. Dragutan, L. Delaude, A. Demonceau, A.F. Noels, “N-Heterocyclic Carbene Ruthenium Complexes: Synthesis and Catalytic Properties”, Rev. Roumaine Chim. 2007, 52(11),1013-1025; e. V. Dragutan, I. Dragutan, L. Delaude, A. Demonceau, “NHC-Ru Complexes - Friendly Catalytic Tools for Manifold Chemical Transformations”, Coord. Chem. Rev. 2007, 251, pp 765-794.
10. a. K. Ferré-Filmon, L. Delaude, A. Demonceau, A.F. Noels, Coord. Chem. Rev. 2004, 248, 2323-2336 ; b. X. Sauvage, Ph.D. Thesis, University of Liège.