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Grubbs’ first-generation catalyst

Hoveyda and coworkers [227] used a domino process to give chromanes 6/3-8 by treatment of 6/3-7 in the presence of ethylene. One of the first-generation Grubbs catalyst 6/3-9 and one of Blechert s [228] early examples allowed the synthesis of bicyclic compounds of different sizes, depending on the length of the tether thus, the reaction of 6/3-10 led to 6/3-11 using 30 mol% of the Schrock Mo complex 6/3-12. [Pg.440]

The main reason for the rapid development of metathesis reactions on a laboratory scale (the reaction itself had been known for quite a long time) has been the development of active and robust second-generation ruthenium catalysts (6/3-14 to 6/3-16), which usually provide better yields than the first-generation Grubbs catalysts (6/3-9 or 6/3-13) (Scheme 6/3.2). This also reflects the huge number of domino processes based on ruthenium-catalyzed metathesis, which is usually followed by a second or even a third metathesis reaction. However, examples also exist where, after a metathesis, a second transition metal-catalyzed transformation or a pericyclic reaction takes place. [Pg.441]

The tetrahydro- and perhydropyrrolo[l,2- ]isothiazoles 367 and 368 were synthesized as sulfone derivatives from an olefin metathesis of the diene 366 with the first-generation Grubbs catalyst followed by hydrogenation under palladium on charcoal (Scheme 54) <2003T7047>. [Pg.93]

The allenylidene-ruthenium(arene) catalyst precursors I have been used for the synthesis of macrocycles by the RCM reaction and were revealed as active as the first generation Grubbs catalyst RuCl2(=CHPh)(PCy3)2 [35], depending on the nature of the diene functional groups and macrocyde size [32] (Scheme 8.3).These macrocyde syntheses show that the allenylidene mthenium catalysts I offer functional group tolerance. [Pg.254]

The even more spectacular cyclization of 7 to Arenastatin A 8 was reported (Tetrahedron Lett. 45 5309,2004) by Gunda Georg of the University of Kansas. In this case, the catalyst used was the first generation Grubbs catalyst, 9. [Pg.40]

Selectivity can sometimes be achieved by changing the Ru catalyst. James Panek of Boston University, reported (Organic belt. 2004, 6, 525) that the attempted conversion of 6 to the tetraene macrolactam core 7 of the cyclotrienins led instead to the unwanted 8. Use of the less-reactive first generation Grubbs catalyst 9 gave clean cyclization to the desired 7. [Pg.154]

Burdett, K.A., L.D. Harris, P. Margl, B.R. Maughon, T. Mokhtar-Zadeh, P.C. Saucier and E.P. Wasserman, Renewable Monomer Feedstocks Via Olefin Metathesis Fundamental Mechanistic Studies of Methyl Oleate Ethenolysis with the First-Generation Grubbs Catalyst, Organometallics, 23, 2027-2047 (2004). [Pg.72]

Dihydropyrrolizine 16 was obtained from 15 by ring-closing metathesis using commercial first generation Grubbs catalyst (Scheme 10) <2002TL4765, CHEC-III(11.01.7.2)21>. [Pg.892]

Scheme 8.21 Preparation of the carbene ruthenium(II) complex 81, the first representative of the first generation Grubbs catalysts", from 79 and 3,3-diphenylcyclopropene via the related ruthenium carbene 80 as the intermediate... Scheme 8.21 Preparation of the carbene ruthenium(II) complex 81, the first representative of the first generation Grubbs catalysts", from 79 and 3,3-diphenylcyclopropene via the related ruthenium carbene 80 as the intermediate...
Scheme 8.23 Preparation of Herrmann s bis(NHC) ruthenium(II) complexes 84 and the mono(NHC) complexes 85 and 86 from the first generation Grubbs catalyst 83b (X = H) as the precursor... Scheme 8.23 Preparation of Herrmann s bis(NHC) ruthenium(II) complexes 84 and the mono(NHC) complexes 85 and 86 from the first generation Grubbs catalyst 83b (X = H) as the precursor...
Scheme 12 Substitution of phosphine ligands in first-generation Grubbs catalyst... Scheme 12 Substitution of phosphine ligands in first-generation Grubbs catalyst...
In 1998, Hernnann reported that first-generation Grubbs catalyst [RuCl2(PCy3)2(CHPh)] (72) (Scheme 12) nnderwent snbstitntion of the two phosphines by two eqnivalents of alkyl carbene affording complex (74). On the other hand, when only a slight excess of the free carbene was added mono-substitntion of phosphine was achieved, and complex (73) was obtained. ... [Pg.6624]

Conformationally constrained a-Boc-aminophosphonates (387), (388) (389), (390) and (391) were made via a transition metal catalysed Curtins rearrangement. The conformational constraint involved either a ring-closing metathesis reaction catalysed by the first generation Grubbs catalyst or intramolecular cyclopropanation mediated by Rh2(OAc)4 (Figure 66). ... [Pg.361]

The first enantioselective total synthesis of (+)-prelaureatin was achieved by M.T. Crimmins et al. The oxocene core of the natural product was constructed in high yield by a RCM reaction using the first generation Grubbs catalyst. [Pg.11]

This procedure can be followed by phosphine exchange to give catalyst 6. Complex 6 can be stirred under an atmosphere of ethylene to give quantitative yield of the methylidene complex 7, which was the first isolable and metathesis-active metal methylidene complex reported in the literature [81] (Scheme 6.21). Complex 6 is the most widely used catalyst of this series, and is commonly referred to as fhe Grubbs catalyst or more recently as the first-generation Grubbs catalyst . [Pg.209]

Crabbs Catalysts for Ring Closing Metathesis 5.2.8.2.1 First Generation Grubbs catalyst... [Pg.182]

Scheme 74. Tandem ring-closing enyne metathesis using first generation Grubbs catalyst to form... Scheme 74. Tandem ring-closing enyne metathesis using first generation Grubbs catalyst to form...
Scheme 75. Tandem diyne-ene cross-metathesis to yield cyclic trienes via first generation Grubbs catalyst. Scheme 75. Tandem diyne-ene cross-metathesis to yield cyclic trienes via first generation Grubbs catalyst.

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See also in sourсe #XX -- [ Pg.355 ]




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Grubbs’s first-generation catalyst

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