Catalyst Grubb

Schrock s catalyst Grubbs s catalyst Catalyst in Figure 14-24... 

Recent years have seen rapid advancements in development of W, Mo, and Ru carbene complexes that serve not only as catalysts for metathesis of small molecules (Section 11-1-3) but also as ROMP catalysts. Grubbs use of a Ru(III) catalyst for ROMP in aqueous medium helped pave the way for development of his first- and second-generation Ru alkylidenes, which also catalyze ROMP. The Schrock catalysts that we have encountered already (compounds 15... 

Strong Lewis acids such as FAB can also be used for generating active neutral Ni(II) ethylene polymerization catalysts. Grubbs et al. reported that... 

Work has been performed in which the quaternary pyridinium functionality was attached to 7-oxanorbornene-5,6-exo-dicarboximide-functionalised monomers which were subsequently polymerised using a Grubbs catalyst (Grubbs catalysts are a series of transition metal carbene complexes used as catalysts for olefin metathesis). The polymer series, a-f, and quaternised polymer, a , (Figure 9.1 and Table 9.1) was designed to study the effect of the hydrophobic alkyl substituent on the antibacterial and haemolytic activities of polymers using dimethylformamide (DMF) as the solvent. 

From a highly prepared mmiocyclic precursor, reaction with the Grubbs second-generation catalyst (Grubbs II) furnished the tricyclic intermediate for the guanacastepenes (Scheme 14) [49]. It is now possible to predict the... 

The RCM reaction between a double bond and a simple triple bmid, the enyne RCM, produces a diene system with no loss of the terminal carbon atoms. This approach leads to a useful intermediate for the micrandUactones (Scheme 15) [50], The reactimi requires the catalyst Grubbs 11 possibly due to the presence of the propargylic acetate group. 

Figure 5.1 Alkene metathesis catalysts Grubbs-type first generation, second generation, and third generation. (From left side, top row to right side, second row) Grubbs-Blechert-Hoveyda catalyst, Grela s nitro derivative, and Schrock-type catalyst [7-11].

Some restrictions arising from the distribution of the reactive sites and the pores in the resin beads may also increase the selectivity of the substrate. This has been observed in the case of hydrogenation using polymer-supported catalysts (Grubbs and Kroll, 1971). 

Figure 2 Metathesis catalysts Grubbs first-generation catalyst (5), Grubbs second-generation catalyst (6), Hoveyda—Grubbs catalyst (7), and Grubbs—Nolan catalyst (8).

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