Cross-Metathesis of Vinyl Halides. Scope and Limitations of Ruthenium-Based Catalysts

Macnaughtan, Marisa L.; Gary, J. Brannon; Gerlach, Deidra L.; Johnson, Mark; Kampf, Jeff W.

doi:10.1021/om800463n

Cited by 73 publications

(58 citation statements)

References 37 publications

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“…Fluoro-, chloro-, or bromo-substituted Fischer-type Ru complexes show negligible activity ( Ru-1b , Fig. 1b) 34 . With phosphine-containing systems (e.g., Ru-1a ) inactive species such as phosphoniomethylidene Ru-1c and carbide Ru-1d 32 are produced.…”

Section: The Potential and Challenge Of Alkenyl Halide Cross-metathesismentioning

confidence: 99%

“…Unlike Ru carbenes or Mo or W alkylidenes with alkyl, aryl, boryl or alkoxy substituents, those bearing a halogen atom are either unstable (Ru), their transformations inefficient (Ru) 32,33,34 or there is hardly anything known about them (Mo/W). Fluoro-, chloro-, or bromo-substituted Fischer-type Ru complexes show negligible activity ( Ru-1b , Fig.…”

Section: The Potential and Challenge Of Alkenyl Halide Cross-metathesismentioning

confidence: 99%

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Direct synthesis of Z-alkenyl halides through catalytic cross-metathesis

Koh

Nguyen

Zhang

et al. 2016

Nature

167

117

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Olefin metathesis has made a significant impact on modern organic chemistry, but important shortcomings remain: for example, the lack of efficient processes that can be used to generate acyclic alkenyl halides. Halo-substituted ruthenium carbene complexes decompose rapidly or deliver low activity and/or minimal stereoselectivity, and our understanding of the corresponding high-oxidation-state systems is very limited. In this manuscript, we show that previously unknown halo-substituted molybdenum alkylidene species are exceptionally reactive and are able to participate in high-yielding olefin metathesis reactions that afford acyclic 1,2-disubstituted Z-alkenyl halides. Transformations are promoted by small amounts of an in situ-generated catalyst with unpurified, commercially available and easy-to-handle liquid 1,2-dihaloethene reagents and proceed to high conversion at ambient temperature within four hours. Many alkenyl chlorides, bromides and fluorides can be obtained in up to 91 percent yield and complete Z selectivity. This method can be used to easily synthesize biologically active compounds and to perform the site- and stereoselective fluorination of other organic compounds.

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Section: The Potential and Challenge Of Alkenyl Halide Cross-metathesismentioning

confidence: 99%

Section: The Potential and Challenge Of Alkenyl Halide Cross-metathesismentioning

confidence: 99%

Direct synthesis of Z-alkenyl halides through catalytic cross-metathesis

Koh

Nguyen

Zhang

et al. 2016

Nature

167

117

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“…Ruthenium metathesis catalysts proved to be less stable in the presence of alkenyl halides, due to the formation of Fischer-type carbenes and catalyst decomposition, requiring high catalyst loadings for good yields. [95][96][97] Studies in the cross metathesis of alkenyl halides from Schrock, Hoveyda, and coworkers commenced using the cross metathesis system of 8-bromo-1-octene and Z-1,2-dichloroethene (Table 7). Catalysts 16 and 17 provided minimal desired product (Table 7, entries 1 and 2), showing preference for the cross metathesis of the terminal olefin.…”

Section: Z-selectivity Through Stereoretentionmentioning

confidence: 99%

Stereoretentive Olefin Metathesis: An Avenue to Kinetic Selectivity

2017

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Abstract:Olefin metathesis is an incredibly valuable transformation that has gained widespread use in both academic and industrial settings. Lately, stereoretentive olefin metathesis has garnered much attention as a method for the selective generation of both Eand Z-olefins. Early studies employing ill-defined catalysts showed evidence for retention of the starting olefins at early conversion. However, thermodynamic ratios were reached as the reaction proceeded to equilibrium. Recent studies in olefin metathesis have focused on the synthesis of catalysts that can overcome the inherent thermodynamic preference of an olefin, providing synthetically useful quantities of a kinetically favored olefin isomer. These reports have led to the development of stereoretentive catalysts that not only generate Z-olefins selectively, but also kinetically produce E-olefins, a previously unmet challenge in olefin metathesis. Advancements in stereoretentive olefin metathesis using tungsten, ruthenium, and molybdenum catalysts are presented.

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“…Vinyl sulfides are very important synthetic intermediates in total syntheses. The properties have already been exploited widely in organic transformations [13], e.g., thio-Claisen [14][15][16], Diels-Alder [17,18], and Michael acceptors [19], ranging from enol substitutes [20] to olefin metathesis [21,22], although stereo-and regio-selectivity control still remains a significant challenge. In the past few years, the application of transition metal and f-element catalysts to this transformation has received a surge of attention.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of the palladium-catalyzed hydrothiolation of alkynes to thioethers: a DFT study

et al. 2014

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The mechanisms of the palladium-catalyzed hydrothiolation of alkynes with thiols were investigated using density functional theory at the B3LYP/6-31G(d, p) (SDD for Pd) level. Solvent effects on these reactions were explored using the polarizable continuum model (PCM) for the solvent tetrahydrofuran (THF). Markovnikov-type vinyl sulfides or cis-configured anti-Markovnikov-type products were formed by three possible pathways. Our calculation results suggested the following: (1) the first step of the cycle is a proton-transfer process from thiols onto the palladium atom to form a palladium-thiolate intermediate. The palladium-thiolate species is attacked on alkynes to obtain an elimination product, liberating the catalyst. (2) The higher activation energies for the alkyne into the palladium-thiolate bond indicate that this step is the rate-determining step. The Markovnikov-type vinyl sulfide product is favored. However, for the aromatic alkyne, the cis-configured anti-Markovnikov-type product is favored. (3) The activation energy would reduce when thiols are substituted with an aromatic group. Our calculated results are consistent with the experimental observations of Frech and colleagues for the palladium-catalyzed hydrothiolation of alkynes to thiols.

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Cross-Metathesis of Vinyl Halides. Scope and Limitations of Ruthenium-Based Catalysts

Cited by 73 publications

References 37 publications

Direct synthesis of Z-alkenyl halides through catalytic cross-metathesis

Direct synthesis of Z-alkenyl halides through catalytic cross-metathesis

Stereoretentive Olefin Metathesis: An Avenue to Kinetic Selectivity

Mechanism of the palladium-catalyzed hydrothiolation of alkynes to thioethers: a DFT study

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