Effect of Brønsted Acid on the Reactivity and Selectivity of the Oxoiron(V) Intermediates in C-H and C=C Oxidation Reactions
The effect of HClO<sub>4</sub> on the reactivity and selectivity of the catalyst systems <b>1</b>,<b>2</b>/H<sub>2</sub>O<sub>2</sub>/AcOH, based on nonheme iron complexes of the PDP families, [(<sup>Me2OMe</sup>PDP)Fe<sup>...
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MDPI AG
2022-08-01
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| Series: | Catalysts |
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| Online Access: | https://www.mdpi.com/2073-4344/12/9/949 |
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| author | Alexandra M. Zima Oleg Y. Lyakin Anna A. Bryliakova Dmitrii E. Babushkin Konstantin P. Bryliakov Evgenii P. Talsi |
| author_facet | Alexandra M. Zima Oleg Y. Lyakin Anna A. Bryliakova Dmitrii E. Babushkin Konstantin P. Bryliakov Evgenii P. Talsi |
| author_sort | Alexandra M. Zima |
| collection | DOAJ |
| description | The effect of HClO<sub>4</sub> on the reactivity and selectivity of the catalyst systems <b>1</b>,<b>2</b>/H<sub>2</sub>O<sub>2</sub>/AcOH, based on nonheme iron complexes of the PDP families, [(<sup>Me2OMe</sup>PDP)Fe<sup>III</sup>(μ-OH)<sub>2</sub>Fe<sup>III</sup>(<sup>MeOMe2</sup>PDP)](OTf)<sub>4</sub> (<b>1</b>) and [(<sup>NMe2</sup>PDP)Fe<sup>III</sup>(μ-OH)<sub>2</sub>Fe<sup>III</sup>(<sup>NMe2</sup>PDP](OTf)<sub>4</sub> (<b>2</b>), toward oxidation of benzylideneacetone (<b>bna</b>), adamantane (<b>ada</b>), and (3a<i>R</i>)-(+)-sclareolide (<b>S</b>) has been studied. Adding HClO<sub>4</sub> (2–10 equiv. vs. Fe) has been found to result in the simultaneous improvement of the observed catalytic efficiency (i.e., product yields) and the oxidation regio- or enantioselectivity. At the same time, HClO<sub>4</sub> causes a threefold increase of the second-order rate constant for the reaction of the key oxygen-transferring intermediate [(<sup>Me2OMe</sup>PDP)Fe<sup>V</sup>=O(OAc)]<sup>2+</sup> (<b>1a</b>), with cyclohexane at −70 °C. The effect of strong Brønsted acid on the catalytic reactivity is discussed in terms of the reversible protonation of the Fe=O moiety of the parent perferryl intermediates. |
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| issn | 2073-4344 |
| language | English |
| last_indexed | 2024-03-10T00:29:04Z |
| publishDate | 2022-08-01 |
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| spelling | doaj.art-df4608233e6e4f258cc1374c39799a232023-11-23T15:29:47ZengMDPI AGCatalysts2073-43442022-08-0112994910.3390/catal12090949Effect of Brønsted Acid on the Reactivity and Selectivity of the Oxoiron(V) Intermediates in C-H and C=C Oxidation ReactionsAlexandra M. Zima0Oleg Y. Lyakin1Anna A. Bryliakova2Dmitrii E. Babushkin3Konstantin P. Bryliakov4Evgenii P. Talsi5Boreskov Institute of Catalysis, Pr. Lavrentieva 5, 630090 Novosibirsk, RussiaBoreskov Institute of Catalysis, Pr. Lavrentieva 5, 630090 Novosibirsk, RussiaBoreskov Institute of Catalysis, Pr. Lavrentieva 5, 630090 Novosibirsk, RussiaBoreskov Institute of Catalysis, Pr. Lavrentieva 5, 630090 Novosibirsk, RussiaBoreskov Institute of Catalysis, Pr. Lavrentieva 5, 630090 Novosibirsk, RussiaBoreskov Institute of Catalysis, Pr. Lavrentieva 5, 630090 Novosibirsk, RussiaThe effect of HClO<sub>4</sub> on the reactivity and selectivity of the catalyst systems <b>1</b>,<b>2</b>/H<sub>2</sub>O<sub>2</sub>/AcOH, based on nonheme iron complexes of the PDP families, [(<sup>Me2OMe</sup>PDP)Fe<sup>III</sup>(μ-OH)<sub>2</sub>Fe<sup>III</sup>(<sup>MeOMe2</sup>PDP)](OTf)<sub>4</sub> (<b>1</b>) and [(<sup>NMe2</sup>PDP)Fe<sup>III</sup>(μ-OH)<sub>2</sub>Fe<sup>III</sup>(<sup>NMe2</sup>PDP](OTf)<sub>4</sub> (<b>2</b>), toward oxidation of benzylideneacetone (<b>bna</b>), adamantane (<b>ada</b>), and (3a<i>R</i>)-(+)-sclareolide (<b>S</b>) has been studied. Adding HClO<sub>4</sub> (2–10 equiv. vs. Fe) has been found to result in the simultaneous improvement of the observed catalytic efficiency (i.e., product yields) and the oxidation regio- or enantioselectivity. At the same time, HClO<sub>4</sub> causes a threefold increase of the second-order rate constant for the reaction of the key oxygen-transferring intermediate [(<sup>Me2OMe</sup>PDP)Fe<sup>V</sup>=O(OAc)]<sup>2+</sup> (<b>1a</b>), with cyclohexane at −70 °C. The effect of strong Brønsted acid on the catalytic reactivity is discussed in terms of the reversible protonation of the Fe=O moiety of the parent perferryl intermediates.https://www.mdpi.com/2073-4344/12/9/949C-H activationoxidationironintermediatemechanismnon-heme |
| spellingShingle | Alexandra M. Zima Oleg Y. Lyakin Anna A. Bryliakova Dmitrii E. Babushkin Konstantin P. Bryliakov Evgenii P. Talsi Effect of Brønsted Acid on the Reactivity and Selectivity of the Oxoiron(V) Intermediates in C-H and C=C Oxidation Reactions Catalysts C-H activation oxidation iron intermediate mechanism non-heme |
| title | Effect of Brønsted Acid on the Reactivity and Selectivity of the Oxoiron(V) Intermediates in C-H and C=C Oxidation Reactions |
| title_full | Effect of Brønsted Acid on the Reactivity and Selectivity of the Oxoiron(V) Intermediates in C-H and C=C Oxidation Reactions |
| title_fullStr | Effect of Brønsted Acid on the Reactivity and Selectivity of the Oxoiron(V) Intermediates in C-H and C=C Oxidation Reactions |
| title_full_unstemmed | Effect of Brønsted Acid on the Reactivity and Selectivity of the Oxoiron(V) Intermediates in C-H and C=C Oxidation Reactions |
| title_short | Effect of Brønsted Acid on the Reactivity and Selectivity of the Oxoiron(V) Intermediates in C-H and C=C Oxidation Reactions |
| title_sort | effect of bronsted acid on the reactivity and selectivity of the oxoiron v intermediates in c h and c c oxidation reactions |
| topic | C-H activation oxidation iron intermediate mechanism non-heme |
| url | https://www.mdpi.com/2073-4344/12/9/949 |
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