Ring Closing Metathesis (RCM)
The Ring-Closing Metathesis (RCM) allows synthesis of 5- up to 30-membered cyclic alkenes. The E/Z-selectivity depends on the ring strain.
The Ru-catalysts used tolerate a variety of functional groups, but normally the molecule must have polar side chains that are able to build a template for the catalyst. The modern Second Generation Grubb's Catalysts (see Olefin Metathesis) are more versatile.
Mechanism of Ring Closing Metathesis
The key intermediate is a metallacyclobutane, which can undergo cycloreversion either towards products or back to starting materials. When the olefins of the substrate are terminal, the driving force for RCM is the removal of ethene from the reaction mixture.
Indenylidene Ruthenium Complex Bearing a Sterically Demanding NHC Ligand: An Efficient Catalyst for Olefin Metathesis at Room Temperature
H. Clavier, C. A. Urbino-Blanco, S. P. Nolan, Organometallics, 2009, 28, 2848-2854.
Aminocarbonyl Group Containing Hoveyda-Grubbs-Type Complexes: Synthesis and Activity in Olefin Metathesis Transformations
D. Rix, F. Caijo, I. Laurent, F. Boeda, H. Clavier, S. P. Nolan, M. Mauduit, J. Org. Chem., 2008, 73, 4225-4228.
Pd, Ru, and Fe catalysis enable a general synthesis of 2-substituted pyrroles in overall good yields with only water and ethene as side-products. The route starts with two subsequent Pd-catalyzed monoallylations of amines with allylic alcohols. Ru-catalyzed ring-closing metathesis performed on the diallylated amines provides pyrrolines in excellent yields. By addition of ferric chloride, a selective aromatization was achieved.
A. Bunrit, S. Sawadjoon, S. Tšupova, P. J. R. Sjöberg, J. S. M. Samec, J. Org. Chem., 2016, 81, 1450-1460.
Synthesis of Imidazolium-Tagged Ruthenium Carbene Complex: Remarkable Activity and Reusability in Regard to Olefin Metathesis in Ionic Liquids
H. Wakamatsu, Y. Saito, M. Masubuchi, R. Fujita, Synlett, 2008, 1805-1808.
Allenylidene-to-Indenylidene Rearrangement in Arene-Ruthenium Complexes: A Key Step to Highly Active Catalysts for Olefin Metathesis Reactions
R. Castarlenas, C. Vovard, C. Fischmeister, P. H. Dixneuf, J. Am. Chem. Soc., 2006, 128, 4079-4089.
Advanced Fine-Tuning of Grubbs/Hoveyda Olefin Metathesis Catalysts: A Further Step toward an Optimum Balance between Antinomic Properties
M. Bieniek, R. Bujok, M. Cabaj, N. Lugan, G. Lavigne, D. Arlt, K. Grela, J. Am. Chem. Soc., 2006, 128, 13652-13653.
Δ3-Aryl/heteroaryl substituted heterocycles via sequential Pd-catalysed termolecular cascade/ring closing metathesis (RCM)
H. A. Dondas, B. Clique, B. Cetinkaya, R. Grigg, C. Kilner, J. Morris, V. Sridharan, Tetrahedron, 2005, 61, 10652-10666.
Synthesis of Nitrogen-Containing Heterocycles via Ring-Closing Ene-Ene and Ene-Yne Metathesis Reactions: An Easy Access to 1- and 2-Benzazepine Scaffolds and Five- and Six-Membered Lactams
E. Benedetti, M. Lomazzi, F. Tibiletti, J.-P. Goddard, L. Fensterbank, M. Malacria, G. Palmisano, A. Penoni, Synthesis, 2012, 44, 3523-3533.
Enantioselective Synthesis of Cyclic Amides and Amines through Mo-Catalyzed Asymmetric Ring-Closing Metathesis
E. S. Sattely, G. Alexander Cortez, D. C. Moebius, R. R. Schrock, A. H. Hoveyda, J. Am. Chem. Soc., 2005, 127, 8526-8533.
An isomerization-ring-closing metathesis strategy for the synthesis of substituted benzofurans
W. A. L. van Otterlo, G. L. Morgans, L. G. Madeley, S. Kuzvidza, S. S. Moleele, N. Thornton, C. B. de Koning, Tetrahedron, 2005, 61, 7746-7755.
Synthesis of α,β-Unsaturated 4,5-Disubstituted γ-Lactones via Ring-Closing Metathesis Catalyzed by the First-Generation Grubbs' Catalyst
M. Bassetti, A. D'Annibale, A. Fanfoni, F. Minissi, Org. Lett., 2005, 7, 1805-1808.
Highly Active Ruthenium Metathesis Catalysts Exhibiting Unprecedented Activity and Z-Selectivity
L. E. Rosebrugh, M. B. Herbert, V. M. Marx, B. K. Keitz, R. H. Grubbs, J. Am. Chem. Soc., 2013, 135, 1276-1279.
Chelate-Assisted Ring-Closing Metathesis: A Strategy for Accelerating Macrocyclization at Ambient Temperatures
C. S. Higman, D. L. Nascimento, B. J. Ireland, S. Audörsch, G. A. Bailey, R. McDonald, D. E. Fogg, J. Am. Chem. Soc., 2018, 140, 1604-1607.