Transition Metal-Carbene Complexes in Olefin Metathesis and Related Reactions

Transition Metal-Carbene Complexes in Olefin Metathesis and Related Reactions 

Robert H. Grubbs, Tina M. Trnka and Melanie S. Sanford 

Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering California Institute of Technology, Pasadena, CA 91125, USA 

During the past few decades, a wide variety of molecules with transition metal-carhon mulhple bonds have been studied. The chemistry of doubly bonded species - carbenes - is particularly interesting because it leads to several synthetically important transformations, and for this reason, metal carbenes are the main subject of this chapter. Our discussion begins with a classification of metal-carbene complexes based on electronic structure, which provides a way to understand their reactivity patterns. Next, we summarize the mechanistic highlights of three metal-carbene-mediated reactions carbonyl olefinafion, olefin cyclopropanafion, and olefin metathesis. Throughout the second half of the chapter, we focus mainly on ruthenium-carbene olefin metathesis catalysts, in part because of widespread interest in the applications of these catalysts, and in part because of our expertise in this area. We conclude with some perspectives on the chemistry of metal carbenes and on future developments in catalysis. 

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Grubbs, R. H., Trnka, T. M., Sanford, M. S. Transition metal-carbene complexes in olefin metathesis and related reactions. Current Methods in Inorganic Chemistry 2003, 3, 187-231. 

For discussions on pathways available for cyclopropanation, see (a) C. P. Casey, Metal-Carbene Complexes in Organic Synthesis, in Transition Metal Organometallics in Organic Synthesis, H. Alper, Ed, Academic Press New York, 1976, Vol. 1, pp. 189-233 (b) M. Brookhart and W. B. Studabaker, Chem. Rev., 1987, 87, 411 and (c) R. H. Grubbs, T. M. Trnka, and M. S. Sanford, Transition Metal-Carbene Complexes in Olefin Metathesis and Related Reactions, in Fundamentals of Molecular Catalysis, H. Kurosawa and A. Yamamoto, Eds, Elsevier Amsterdam, 2003, pp. 187-231. 

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