Superelectrophilic aluminium(iii)–ion pairs promote a distinct reaction path for carbonyl–olefin ring-closing metathesis

Davis, Ashlee J.; Watson, Rebecca B.; Nasrallah, Daniel J.; Gomez-Lopez, Jessica L.; Schindler, Corinna S.

doi:10.1038/s41929-020-00499-5

Cited by 29 publications

(27 citation statements)

References 55 publications

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“…Indeed, the reaction went to completeness at rt during 24 h without any observable side reactions. In light of the previous restriction to metal halide catalysts for the COM (e. g., MCl 3 , M=Fe, Al, Ga, Au),[ 18c , 19 ] this is very promising as it ultimately allows to tackle selectivity by ligand design in future. Overall, the first deoxygenation reactions catalyzed by a neutral silane and the first silicon catalyzed carbonyl‐olefin metathesis are realized, clearly broadening silicon's reach in homogeneous catalysis.…”

Section: Resultsmentioning

confidence: 99%

“…To probe a Lewis acid catalysis beyond reductions, and inspired by the fact, that the carbonyl-olefin metathesis (COM) critically depends on the strength of a Lewis acid, [18] the cyclization of A with 5 mol% of 1-(sulfolane) 2 was attempted (Figure 5d). Indeed, the reaction went to completeness at rt during 24 h without any observable side reactions.…”

Section: Resultsmentioning

confidence: 99%

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Bis(pertrifluoromethylcatecholato)silane: Extreme Lewis Acidity Broadens the Catalytic Portfolio of Silicon

Thorwart

Roth

Greb

2021

Chemistry A European J

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Given its earth abundance, silicon is ideal for constructing Lewis acids of use in catalysis or materials science. Neutral silanes were limited to moderate Lewis acidity, until halogenated catecholato ligands provoked a significant boost. However, catalytic applications of bis (perhalocatecholato)silanes were suffering from very poor solubility and unknown deactivation pathways. In this work, the novel per(trifluoromethyl)catechol, H 2 cat CF3 , and adducts of its silicon complex Si(cat CF3 ) 2 (1) are described. According to the computed fluoride ion affinity, 1 ranks among the strongest neutral Lewis acids currently accessible in the condensed phase. The improved robustness and affinity of 1 enable deoxygenations of aldehydes, ketones, amides, or phosphine oxides, and a carbonyl-olefin metathesis. All those transformations have never been catalyzed by a neutral silane. Attempts to obtain donor-free 1 attest to the extreme Lewis acidity by stabilizing adducts with even the weakest donors, such as benzophenone or hexaethyl disiloxane.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Bis(pertrifluoromethylcatecholato)silane: Extreme Lewis Acidity Broadens the Catalytic Portfolio of Silicon

Thorwart

Roth

Greb

2021

Chemistry A European J

View full text Add to dashboard Cite

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“…It is of particular interest to understand current limitations [13] in carbonyl olefin metathesis ring‐closing reactions and the specific reactivity for the preferential formation of cyclopentenes. The corresponding cyclobutenes or cyclohexenes are not favored products from COM cyclization and highly specialized catalysts are required in scarce number of reports for the latter [12f, 18b] . We therefore carried out computational studies on the COM reaction pathway and all other reaction pathways observed for different chain length of the alkenyl carbon skeleton (Scheme 4).…”

Section: Resultsmentioning

confidence: 99%

Hydrogen Bonding Networks Enable Brønsted Acid‐Catalyzed Carbonyl‐Olefin Metathesis**

Pei

Koenigs

et al. 2022

Angewandte Chemie

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Synthetic chemists have learned to mimic nature in using hydrogen bonds and other weak interactions to dictate the spatial arrangement of reaction substrates and to stabilize transition states to enable highly efficient and selective reactions. The activation of a catalyst molecule itself by hydrogen‐bonding networks, in order to enhance its catalytic activity to achieve a desired reaction outcome, is less explored in organic synthesis, despite being a commonly found phenomenon in nature. Herein, we show our investigation into this underexplored area by studying the promotion of carbonyl‐olefin metathesis reactions by hydrogen‐bonding‐assisted Brønsted acid catalysis, using hexafluoroisopropanol (HFIP) solvent in combination with para‐toluenesulfonic acid (pTSA). Our experimental and computational mechanistic studies reveal not only an interesting role of HFIP solvent in assisting pTSA Brønsted acid catalyst, but also insightful knowledge about the current limitations of the carbonyl‐olefin metathesis reaction.

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“…The corresponding cyclobutenes or cyclohexenes are not favored products from COM cyclization and highly specialized catalysts are required in scarce number of reports for the latter. 27,28 We therefore carried out computational studies on the COM reaction pathway and all other reaction pathways observed for different chain length of the alkenyl carbon skeleton (Scheme 4). The analysis of the first reaction step showed a distinct effect of the carbon chain length on the activation free energy for C-C bond formation (TS1).…”

Section: Substrate Scope and Further Applicationsmentioning

confidence: 99%

Biomimetic Brønsted Acid-Catalyzed Carbonyl-Olefin Metathesis Enabled by Hydrogen Bonding Networks

Pei

Koenigs

et al. 2021

Preprint

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Synthetic chemists have learned to mimic nature in using hydrogen bonds and other weak interactions to dictate the spatial arrangement of reaction substrates and to stabilize transition states to enable highly efficient and selective reactions. The activation of a catalyst molecule itself by hydrogen bonding networks, in order to control its catalytic activity to achieve desired reaction outcomes is much less explored in organic synthesis, despite being a common strategy in nature.Herein, we show our investigation into this underexplored area by studying the promotion of carbonylolefin metathesis reactions by hydrogen bonding-assisted Brønsted acid catalysis. The carbonyl-olefin metathesis reaction has recently emerged as a powerful synthetic tool for functional group interconversion of carbonyls and alkenes. However, the application of Brønsted acid catalysts in carbonyl-olefin metathesis reaction, especially in homogeneous conditions, remains scarce and poorly understood. In this work, we report the use of hexafluoroisopropanol solvent in combination with para-toluenesulfonic acid to efficiently catalyze carbonyl-olefin metathesis reactions. Our experimental and computational mechanistic studies reveal not only an interesting role of HFIP solvent in assisting this Brønsted acid catalyzed reaction but also insightful knowledge about the current limitations of the carbonyl-olefin metathesis reaction.

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Superelectrophilic aluminium(iii)–ion pairs promote a distinct reaction path for carbonyl–olefin ring-closing metathesis

Cited by 29 publications

References 55 publications

Bis(pertrifluoromethylcatecholato)silane: Extreme Lewis Acidity Broadens the Catalytic Portfolio of Silicon

Bis(pertrifluoromethylcatecholato)silane: Extreme Lewis Acidity Broadens the Catalytic Portfolio of Silicon

Hydrogen Bonding Networks Enable Brønsted Acid‐Catalyzed Carbonyl‐Olefin Metathesis**

Biomimetic Brønsted Acid-Catalyzed Carbonyl-Olefin Metathesis Enabled by Hydrogen Bonding Networks

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