A Facile, Convenient, and Green Route to (E)-Propenylbenzene Flavors and Fragrances by Alkene Isomerization

Larsen, Casey R.; Paulson, Erik R.; Erdogan, Gulin; Grotjahn, Douglas B.

doi:10.1055/s-0035-1560205

Cited by 18 publications

(3 citation statements)

References 38 publications

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“…6,7 Currently, this area of catalysis is severely underdeveloped and dominated by the use of precious metals, specialty organic polymers as supports, and ill-defined active sites in nanoparticles. Notable examples of single-site catalysts include works by Ley, 8 Grotjahn, 9 and Jia 10 which immobilize Ir, Ru, or Rh complexes, respectively, onto ligandmodified organic polymers (Figure 1b). These systems display good catalyst recyclability, but at the expense of reduced catalytic activity and/or E/Z-selectivity in comparison to their homogeneous analogues.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Transition metal-catalyzed alkene isomerization is an appealing approach to reposition an alkene within a molecule (Figure a). , Significant advancements in the field of homogeneously catalyzed isomerization have been made, − but efficient and selective heterogeneous catalysts for isomerization remain sparse, despite the potential to apply the advantages of heterogeneous catalysis (recyclability, added stability, complementary selectivity). , Currently, this area of catalysis is severely underdeveloped and dominated by the use of precious metals, specialty organic polymers as supports, and ill-defined active sites in nanoparticles. Notable examples of single-site catalysts include works by Ley, Grotjahn, and Jia which immobilize Ir, Ru, or Rh complexes, respectively, onto ligand-modified organic polymers (Figure b). These systems display good catalyst recyclability, but at the expense of reduced catalytic activity and/or E / Z -selectivity in comparison to their homogeneous analogues.…”

Section: Introductionmentioning

confidence: 99%

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Alkene Isomerization Using a Heterogeneous Nickel-Hydride Catalyst

Chang,

Kascoutas,

Valentine

et al. 2024

J. Am. Chem. Soc.

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Transition metal-catalyzed alkene isomerization is an enabling technology used to install an alkene distal to its original site. Due to their well-defined structure, homogeneous catalysts can be fine-tuned to optimize reactivity, stereoselectivity, and positional selectivity, but they often suffer from instability and nonrecyclability. Heterogeneous catalysts are generally highly robust but continue to lack active-site specificity and are challenging to rationally improve through structural modification. Known single-site heterogeneous catalysts for alkene isomerization utilize precious metals and bespoke, expensive, and synthetically intense supports. Additionally, they generally have mediocre reactivity, inspiring us to develop a heterogeneous catalyst with an active site made from readily available compounds made of Earth-abundant elements. Previous work demonstrated that a very active homogeneous catalyst is formed upon protonation of Ni[P(OEt)3]4 by H2SO4, generating a [Ni–H]+ active site. This catalyst is incredibly active, but also decomposes readily, which severely limits its utility. Herein we show that by using a solid acid (sulfated zirconia, SZO300), not only is this decomposition prevented, but high activity is maintained, improved selectivity is achieved, and a broader scope of functional groups is tolerated. Preliminary mechanistic experiments suggest that the catalytic reaction likely goes through an intermolecular, two-electron pathway. A detailed kinetic study comparing the state-of-the-art Ni and Pd isomerization catalysts reveals that the highest activity and selectivity is seen with the Ni/SZO300 system. The reactivity of Ni/SZO300, is not limited to alkene isomerization; it is also a competent catalyst for hydroalkenylation, hydroboration, and hydrosilylation, demonstrating the broad application of this heterogeneous catalyst.

show abstract

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Alkene Isomerization Using a Heterogeneous Nickel-Hydride Catalyst

Chang,

Kascoutas,

Valentine

et al. 2024

J. Am. Chem. Soc.

View full text Add to dashboard Cite

show abstract

“…6,7 Currently, this area of catalysis is severely underdeveloped and dominated by the use of precious metals, specialty organic polymers as supports, and ill-defined active sites in nanoparticles. Notable examples of single-site catalysts include works by Ley, 8 Grotjahn, 9 and Jia 10 which immobilize Ir, Ru, or Rh complexes, respectively, onto ligand-modified organic polymers (Figure 1b). These systems display good catalyst recyclability, but at the expense of reduced catalytic activity and/or E/Z-selectivity in comparison to their homogeneous analogues.…”

Section: Introductionmentioning

confidence: 99%

Alkene Isomerization using a Heterogeneous Nickel-Hydride Catalyst

Chang,

Kascoutas,

Valentine

et al. 2024

Preprint

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Transition metal-catalyzed alkene isomerization is an enabling technology used to install an alkene distal to its original site. Due to their well-defined structure, homogeneous catalysts can be fine-tuned to optimize reactivity, stereoselectivity, and positional selectivity, but they often suffer from instability and non-recyclability. Heterogeneous catalysts are generally highly robust but continue to lack active-site specificity and are challenging to rationally improve through structural modification. Known single-site heterogeneous catalysts for alkene isomerization utilize precious metals and bespoke, expensive, and synthetically intense supports. Additionally, they generally have mediocre reactivity, inspiring us to develop a heterogeneous catalyst with an active site made from readily available compounds made of Earth-abundant elements. Previous work demonstrated that a very active homogeneous catalyst is formed upon protonation of Ni[P(OEt)3]4 by H2SO4, generating a [Ni–H]+ active site. This catalyst is incredibly active, but also decomposes readily, which severely limits its utility. Herein we show that by using a solid acid (sulfated zirconia, SZO300), not only is this de-composition prevented, but high activity is maintained, improved selectivity is achieved, and a broader scope of functional groups is tolerated. Preliminary mechanistic experiments suggest that the catalytic reaction likely goes through an intermolecular, two-electron pathway. A detailed kinetic study comparing the state-of-the-art Ni and Pd isomerization catalysts reveals that the highest activity and selectivity is seen with the Ni/SZO300 system. The reactivity of Ni/SZO300, is not limited to alkene isomerization; it is also a competent catalyst for hydroalkenylation, hydroboration, and hydrosilylation, demonstrating the broad application of this heterogeneous catalyst.

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Isomerization and Hydrogenation of Alkenes

Paulson

Grotjahn

2017

Encyclopedia of Inorganic and Bioinorganic Chemistry

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Alkene isomerization and hydrogenation both using H 2 and sacrificial hydrogen donors are important reactions in synthetic chemistry. These reactions are normally catalyzed by second‐ or third‐row transition metals, but there has been significant recent interest in the development of first‐row systems. The different mechanisms for both alkene isomerization and hydrogenation are discussed along with strategies for catalyst modification to improve selectivity.

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A Facile, Convenient, and Green Route to (E)-Propenylbenzene Flavors and Fragrances by Alkene Isomerization

Cited by 18 publications

References 38 publications

Alkene Isomerization Using a Heterogeneous Nickel-Hydride Catalyst

Alkene Isomerization Using a Heterogeneous Nickel-Hydride Catalyst

Alkene Isomerization using a Heterogeneous Nickel-Hydride Catalyst

Isomerization and Hydrogenation of Alkenes

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