Radical and Ionic Mechanisms in Rearrangements of <i>o</i>-Tolyl Aryl Ethers and Amines Initiated by the Grubbs–Stoltz Reagent, Et<sub>3</sub>SiH/KO<i><sup>t</sup></i>Bu
Rearrangements of <i>o-</i>tolyl aryl ethers, amines, and sulfides with the Grubbs–Stoltz reagent (Et<sub>3</sub>SiH + KO<i><sup>t</sup></i>Bu) were recently announced, in which the ethers were converted to <i>o</i>-hydroxydiarylmethanes, w...
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MDPI AG
2021-11-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/26/22/6879 |
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| author | Krystian Kolodziejczak Alexander J. Stewart Tell Tuttle John A. Murphy |
| author_facet | Krystian Kolodziejczak Alexander J. Stewart Tell Tuttle John A. Murphy |
| author_sort | Krystian Kolodziejczak |
| collection | DOAJ |
| description | Rearrangements of <i>o-</i>tolyl aryl ethers, amines, and sulfides with the Grubbs–Stoltz reagent (Et<sub>3</sub>SiH + KO<i><sup>t</sup></i>Bu) were recently announced, in which the ethers were converted to <i>o</i>-hydroxydiarylmethanes, while the (<i>o-</i>tol)(Ar)NH amines were transformed into dihydroacridines. Radical mechanisms were proposed, based on prior evidence for triethylsilyl radicals in this reagent system. A detailed computational investigation of the rearrangements of the aryl tolyl ethers now instead supports an anionic Truce–Smiles rearrangement, where the initial benzyl anion can be formed by either of two pathways: (i) direct deprotonation of the tolyl methyl group under basic conditions or (ii) electron transfer to an initially formed benzyl radical. By contrast, the rearrangements of <i>o-</i>tolyl aryl amines depend on the nature of the amine. Secondary amines undergo deprotonation of the N-H followed by a radical rearrangement, to form dihydroacridines, while tertiary amines form both dihydroacridines and diarylmethanes through radical and/or anionic pathways. Overall, this study highlights the competition between the reactive intermediates formed by the Et<sub>3</sub>SiH/KO<i><sup>t</sup></i>Bu system. |
| first_indexed | 2024-03-10T05:13:55Z |
| format | Article |
| id | doaj.art-03077899a6ae4b57a6121c3f428c75da |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T05:13:55Z |
| publishDate | 2021-11-01 |
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| series | Molecules |
| spelling | doaj.art-03077899a6ae4b57a6121c3f428c75da2023-11-23T00:35:07ZengMDPI AGMolecules1420-30492021-11-012622687910.3390/molecules26226879Radical and Ionic Mechanisms in Rearrangements of <i>o</i>-Tolyl Aryl Ethers and Amines Initiated by the Grubbs–Stoltz Reagent, Et<sub>3</sub>SiH/KO<i><sup>t</sup></i>BuKrystian Kolodziejczak0Alexander J. Stewart1Tell Tuttle2John A. Murphy3Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, UKDepartment of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, UKDepartment of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, UKDepartment of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, UKRearrangements of <i>o-</i>tolyl aryl ethers, amines, and sulfides with the Grubbs–Stoltz reagent (Et<sub>3</sub>SiH + KO<i><sup>t</sup></i>Bu) were recently announced, in which the ethers were converted to <i>o</i>-hydroxydiarylmethanes, while the (<i>o-</i>tol)(Ar)NH amines were transformed into dihydroacridines. Radical mechanisms were proposed, based on prior evidence for triethylsilyl radicals in this reagent system. A detailed computational investigation of the rearrangements of the aryl tolyl ethers now instead supports an anionic Truce–Smiles rearrangement, where the initial benzyl anion can be formed by either of two pathways: (i) direct deprotonation of the tolyl methyl group under basic conditions or (ii) electron transfer to an initially formed benzyl radical. By contrast, the rearrangements of <i>o-</i>tolyl aryl amines depend on the nature of the amine. Secondary amines undergo deprotonation of the N-H followed by a radical rearrangement, to form dihydroacridines, while tertiary amines form both dihydroacridines and diarylmethanes through radical and/or anionic pathways. Overall, this study highlights the competition between the reactive intermediates formed by the Et<sub>3</sub>SiH/KO<i><sup>t</sup></i>Bu system.https://www.mdpi.com/1420-3049/26/22/6879Truce–Smiles rearrangementGrubbs–Stoltz reagentradicalelectron transferaryl substitutiondiarylmethanes |
| spellingShingle | Krystian Kolodziejczak Alexander J. Stewart Tell Tuttle John A. Murphy Radical and Ionic Mechanisms in Rearrangements of <i>o</i>-Tolyl Aryl Ethers and Amines Initiated by the Grubbs–Stoltz Reagent, Et<sub>3</sub>SiH/KO<i><sup>t</sup></i>Bu Molecules Truce–Smiles rearrangement Grubbs–Stoltz reagent radical electron transfer aryl substitution diarylmethanes |
| title | Radical and Ionic Mechanisms in Rearrangements of <i>o</i>-Tolyl Aryl Ethers and Amines Initiated by the Grubbs–Stoltz Reagent, Et<sub>3</sub>SiH/KO<i><sup>t</sup></i>Bu |
| title_full | Radical and Ionic Mechanisms in Rearrangements of <i>o</i>-Tolyl Aryl Ethers and Amines Initiated by the Grubbs–Stoltz Reagent, Et<sub>3</sub>SiH/KO<i><sup>t</sup></i>Bu |
| title_fullStr | Radical and Ionic Mechanisms in Rearrangements of <i>o</i>-Tolyl Aryl Ethers and Amines Initiated by the Grubbs–Stoltz Reagent, Et<sub>3</sub>SiH/KO<i><sup>t</sup></i>Bu |
| title_full_unstemmed | Radical and Ionic Mechanisms in Rearrangements of <i>o</i>-Tolyl Aryl Ethers and Amines Initiated by the Grubbs–Stoltz Reagent, Et<sub>3</sub>SiH/KO<i><sup>t</sup></i>Bu |
| title_short | Radical and Ionic Mechanisms in Rearrangements of <i>o</i>-Tolyl Aryl Ethers and Amines Initiated by the Grubbs–Stoltz Reagent, Et<sub>3</sub>SiH/KO<i><sup>t</sup></i>Bu |
| title_sort | radical and ionic mechanisms in rearrangements of i o i tolyl aryl ethers and amines initiated by the grubbs stoltz reagent et sub 3 sub sih ko i sup t sup i bu |
| topic | Truce–Smiles rearrangement Grubbs–Stoltz reagent radical electron transfer aryl substitution diarylmethanes |
| url | https://www.mdpi.com/1420-3049/26/22/6879 |
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