Regiospecific Epoxidation of Carvone: A Discovery-Oriented Experiment for Understanding the Selectivity and Mechanism of Epoxidation Reactions

Mak, Kendrew Kin Wah; Lai, Yisheng; Siu, Yuk-Hong

doi:10.1021/ed083p1058

Cited by 17 publications

(12 citation statements)

References 22 publications

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“…A distinctive feature of Zr‐abtc in comparison with other Zr‐MOFs was a significant predomination of 1,2‐epoxide over 7,8‐epoxide in the oxidation of carvone, which clearly indicates a nucleophilic oxidation mechanism leading to epoxidation of the more electron‐poor C=C bond in the substrate molecule [11] . In contrast, MIP‐200, UiO‐66, and UiO‐67 gave 1,2‐ and 7,8‐epoxides in comparable amounts, like in the blank experiment, which is more typical of radical oxidations.…”

Section: Resultsmentioning

confidence: 97%

Catalytic Performance of Zr‐Based Metal–Organic Frameworks Zr‐abtc and MIP‐200 in Selective Oxidations with H₂O₂

Maksimchuk

Ivanchikova

Cho

et al. 2021

Chemistry A European J

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The catalytic performance of Zr‐abtc and MIP‐200 metal–organic frameworks consisting of 8‐connected Zr6 clusters and tetratopic linkers was investigated in H2O2‐based selective oxidations and compared with that of 12‐coordinated UiO‐66 and UiO‐67. Zr‐abtc demonstrated advantages in both substrate conversion and product selectivity for epoxidation of electron‐deficient C=C bonds in α,β‐unsaturated ketones. The significant predominance of 1,2‐epoxide in carvone epoxidation, coupled with high sulfone selectivity in thioether oxidation, points to a nucleophilic oxidation mechanism over Zr‐abtc. The superior catalytic performance in the epoxidation of unsaturated ketones correlates with a larger amount of weak basic sites in Zr‐abtc. Electrophilic activation of H2O2 can also be realized, as evidenced by the high activity of Zr‐abtc in epoxidation of the electron‐rich C=C bond in caryophyllene. XRD and FTIR studies confirmed the retention of the Zr‐abtc structure after the catalysis. The low activity of MIP‐200 in H2O2‐based oxidations is most likely related to its specific hydrophilicity, which disfavors adsorption of organic substrates and H2O2.

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Section: Resultsmentioning

confidence: 97%

Catalytic Performance of Zr‐Based Metal–Organic Frameworks Zr‐abtc and MIP‐200 in Selective Oxidations with H₂O₂

Maksimchuk

Ivanchikova

Cho

et al. 2021

Chemistry A European J

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“…According to the literature, carveol epoxidation is the most likely to occur. which further explains low carvone yield (Figure 4) [23][24][25].…”

Section: Carveol Oxidationmentioning

confidence: 97%

Alcohol Oxidation Assisted by Molybdenum Hydrazonato Catalysts Employing Hydroperoxide Oxidants

et al. 2021

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Molybdenum(VI) catalysts were obtained from methanol or acetonitrile by the reaction of [MoO2(C5H7O2)2] and isonicotinoyl- or nicotinoyl-based aroylhydrazones. Reactions in methanol resulted in the formation of the mononuclear complexes [MoO2(L1–4)(MeOH)] (1a–4a), while the ones in acetonitrile provided polynuclear complexes [MoO2(L1–4)]n (1–4). Crystals of polynuclear compound, [MoO2(L3)]n∙H2O (3∙H2O), suitable for X-ray diffraction analysis were obtained by the solvothermal procedure at 110 °C. Complexes were characterized by infrared spectroscopy (IR-ATR), nuclear magnetic resonance (NMR), elemental analysis (EA), and thermogravimetric analysis (TGA). The prepared catalysts were tested in alcohol oxidation reactions. Carveol, cyclohexanol, and butan-2-ol were investigated substrates. Because the alcohol oxidations are very challenging due to various possible pathways, the idea was to test different oxidants, H2O2, TBHP in water and decane, to optimize the researched catalytic system.

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“…The optimized conditions identified from the deconvolution approach (1 mol% Bi(OTf) 3 , 0.2 M THF and 40°C) were applied to other terpene-based epoxides in order to broaden the scope of substrates and increase the structural diversity. First, the epoxidation of different terpenes was achieved by applying known procedures [40,41]. The experimental details can be found in the electronic supplementary material.…”

Section: (B) Substrate Broadeningmentioning

confidence: 99%

Sustainable catalytic rearrangement of terpene-derived epoxides: towards bio-based biscarbonyl monomers

Löser

Rauthe

Meier

et al. 2020

Phil. Trans. R. Soc. A.

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Seeking a sustainable and selective approach for terpene modification, a catalyst deconvolution approach was applied to the Meinwald rearrangement of (+)-limonene oxide as a model substrate to yield dihydrocarvone. In order to identify the most suitable catalyst and reaction conditions, different Lewis acids were evaluated. Bismuth triflate proved to be the most active catalyst under mild reaction conditions, with a low catalyst loading (1 mol%) and a relatively short reaction time (3 h). The optimized reaction conditions were subsequently transferred to other terpene-based epoxides, yielding different bio-based biscarbonyl structures, which constitute interesting and valuable substances, e.g. for polymer synthesis or as fragrances. Monoepoxides derived from ( R )-(−)-carvone and (+)-dihydrocarvone rearranged to the desired products with high selectivities and yields. γ-Terpinene dioxide could be transformed in a double rearrangement to the respective biscarbonyl in moderate yields. A better result was achieved for limonene dioxide after further adjustment of the protocol to reach acceptable yields with a low catalyst loading of 0.1 mol% using 2-methyl tetrahydrofuran as a sustainable solvent. Compared to many procedures described in the literature, this procedure represents a step towards an increased sustainability in terpene modification by considering several principles of Green Chemistry, such as renewable resources, catalysis and mild reaction conditions for elementary chemical transformations. This article is part of a discussion meeting issue ‘Science to enable the circular economy’.

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Regiospecific Epoxidation of Carvone: A Discovery-Oriented Experiment for Understanding the Selectivity and Mechanism of Epoxidation Reactions

Cited by 17 publications

References 22 publications

Catalytic Performance of Zr‐Based Metal–Organic Frameworks Zr‐abtc and MIP‐200 in Selective Oxidations with H₂O₂

Catalytic Performance of Zr‐Based Metal–Organic Frameworks Zr‐abtc and MIP‐200 in Selective Oxidations with H₂O₂

Alcohol Oxidation Assisted by Molybdenum Hydrazonato Catalysts Employing Hydroperoxide Oxidants

Sustainable catalytic rearrangement of terpene-derived epoxides: towards bio-based biscarbonyl monomers

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Regiospecific Epoxidation of Carvone: A Discovery-Oriented Experiment for Understanding the Selectivity and Mechanism of Epoxidation Reactions

Cited by 17 publications

References 22 publications

Catalytic Performance of Zr‐Based Metal–Organic Frameworks Zr‐abtc and MIP‐200 in Selective Oxidations with H2O2

Catalytic Performance of Zr‐Based Metal–Organic Frameworks Zr‐abtc and MIP‐200 in Selective Oxidations with H2O2

Alcohol Oxidation Assisted by Molybdenum Hydrazonato Catalysts Employing Hydroperoxide Oxidants

Sustainable catalytic rearrangement of terpene-derived epoxides: towards bio-based biscarbonyl monomers

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Resources

About

Catalytic Performance of Zr‐Based Metal–Organic Frameworks Zr‐abtc and MIP‐200 in Selective Oxidations with H₂O₂

Catalytic Performance of Zr‐Based Metal–Organic Frameworks Zr‐abtc and MIP‐200 in Selective Oxidations with H₂O₂