Grubbs catalyst, olefin metathesis

R.H. Grubbs, Olefin-Metathesis Catalysts for the Preparation of Molecules and Materials, Angew. Chem. Int. Ed. 45, 3760-3765 (2006) [Nobel Lecture],... 

XV. Both the first and second generation Grubbs olefin metathesis catalysts have been shown to isomerize allylic ethers to vinyl ethers that are readily hydrolyzed.It is a decomposition product of the catalyst that was shown to be the isomerization catalyst. ... 

Second generation Grubbs olefin metathesis catalyst... 

Minenkov Y, Occhipinti G, HeyndrickxW, Jensen VR. The Nature of the Barrier to Phosphane Dissociation from Grubbs Olefin Metathesis Catalysts. Eur J Inorg Chem. 2012 (9) 1507-1516. 

On treatment with a Grubbs olefin metathesis catalyst, the compound shown reacted with styrene to give a 95% yield of a product with the molecular formula C25H30O3, which was later used in the synthesis of a metabolite isolated from a species of mollusk. Suggest a reasonable structure for the metathesis product. 

The outstanding performances of five-membered NHC ligands in organometallic chemistry and catalysis prompted Grubbs and co-workers to develop a novel stable four-membered NHC [64]. Following their interest in developing new ruthenium olefin metathesis catalysts, they synthesised and fully characterised complex 51 to study the impact of the architecturally unique NHC ligand on the activity of the Ru-based catalyst [65] (Fig. 3.20). In the RCM of 1 at 40°C in CH Cl with 51 (5 mol% catalyst), the reaction reached completion within 20 min, whereas less than 10 min are required for standard catalysts 14 and 16. It should be noted that catalysts 14 and 16 are able to complete the RCM of 1 with only 1 mol% catalyst at 30°C. 

The Syntheses and Activities of Polystyrene-Supported Olefin Metathesis Catalysts Based on Cl2(PCy3)2Ru = CH-CH=CPh2, S.T. Nguyen, R.H. Grubbs, J. Organomet. Chem. 1995, 497, 195-200. 

Recent mechanistic work has shown that 16 e Ru methylene complexes (such as bisphosphine 11) are slow to re-enter the catalytic cycle. Their reluctance to initiate can result in competitive decomposition see Mechanism and Activity of Ruthenium Olefin Metathesis Catalysts, M.S. Sanford, J.A. Love, R.H. Grubbs,/. 

Jordan, J. R Grubbs, R. H. Small-molecule N-heterocychc-carbene-containing olefin-metathesis catalysts for use in water. Angew. Chem. Int. Ed. 2007, 46, 5152-5155. 

T. M. Tmka and R. H. Grubbs, The Development of L2X2Ru=CHR Olefin Metathesis Catalysts An Organometallic Success Story, Acc. Chem. Res. 2001, 34, 18. 

Trimmer, M. S. Commercial Applications of Ruthenium Olefin Metathesis Catalysts in Polymer Synthesis. In Handbook of Metathesis-, Grubbs, R. H., Ed. Wiley-VCH Weinheim, 2003 Vol. 3, pp 407-H8. 

Subsequently, alternative syntheses of sulfoximine-containing heterocycles were studied, and one such approach was based on Grubbs olefin metathesis reaction. Using the ruthenium carbene complex 39 as catalyst, a wide range of... 

B. Mohr, D.M. Lynn, and R.H. Grubbs, Synthesis of water-soluble, aliphatic phosphines and their application to well-defined ruthenium olefin metathesis catalysts, Organometallics, 15(20) 4317 4325,1996. 

Fig. 3 Olefin metathesis catalysts Schrock tungsten (Cl) and molybdenum (C2) alkylidene complexes, Grubbs first- (C3) and second-generation (C4) catalysts, Hoveyda-Grubbs second-generation catalyst (C5), and Grubbs third-generation catalyst (C6)...

Grubbs first generation metathesis catalyst 145 was found to be an active catalyst for the Kharasch addition, provided its metathesis activity for the chosen olefin is low [206]. Snapper and coworkers found at the same time that the Grubbs I olefin metathesis catalyst is efficient for the Kharasch addition of less activated halides, such as CHC13, 1,1,1-trichloroethane, or ethyl trichloroacetate, to olefins like styrenes, acrylates, or acrolein [207, 208]. 

This approach would neither be possible, nor conceivable, without the advent of modern olefin metathesis catalysts. Figure 3 shows a few of the most commonly used catalysts. In this work, we initially relied upon Schrock s Molybdenum catalyst 6 (7) to effect the ring closures, but now exclusively rely upon the second generation Grubbs ruthenium catalyst 7 (8). 

S. T. Nguyen, R. H. Grubbs, and J. W. Ziller, Synthesis and Activities of New Single-Component, Ruthenium-Based Olefin Metathesis Catalysts, J. Am. Chem. Soc. 115, 9858-9859 (1993). 

M. Scholl, T. M. Trnka, J. P. Morgan, and R. H. Grubbs, Increased Ring Closing Metathesis Activity of Ruthenium-Based Olefin Metathesis Catalysts Coordinated with Imidazolin-2-ylidene Ligands, Tetrahedron Lett. 1999, 2247-2250. 

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

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