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

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.

Initiation:

Catalytic cycle:

Chauvin's Mechanism

---

Recent Literature

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 Fused Bicyclic Imidazoles by Sequential Van Leusen/Ring-Closing Metathesis Reactions
V. Gracias, A. F. Gasiecki, S. W. Djuric, Org. Lett., 2005, 7, 3183-3186.

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 Efficient Route to Benzene and Phenol Derivatives via Ring-Closing Olefin Metathesis
K. Yoshida, S. Horiuchi, N. Iwadate, F. Kawagoe, T. Imamoto, Synlett, 2007, 1561-1562.

A New Synthetic Approach to Phenol Derivatives: Use of Ring-Closing Olefin Metathesis
K. Yoshida, T. Imamoto, J. Am. Chem. Soc., 2005, 127, 10470-10471.

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.

An Olefin Metathesis/Double Bond Isomerization Sequence Catalyzed by an In Situ Generated Ruthenium Hydride Species
B. Schmidt, Eur. J. Org. Chem., 2003, 816-819.

Multicatalytic Processes Using Diverse Transition Metals for the Synthesis of Alkenes
H. Lebel, V. Paquet, J. Am. Chem. Soc., 2004, 126, 11152-11153.

---

Selected Articles

N-Heterocycle Construction by Alkene Metathesis
The Grubbs Reaction in Organic Synthesis
Synthesis of (+)-4,5-Deoxyneodolabelline