Radical and Ionic Mechanisms in Rearrangements of o-Tolyl Aryl Ethers and Amines Initiated by the Grubbs–Stoltz Reagent, Et3SiH/KOtBu
| Autor: | Alexander J. Stewart, Tell Tuttle, Krystian Kolodziejczak, John A. Murphy |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
diarylmethanes
Radical Reactive intermediate Pharmaceutical Science Truce–Smiles rearrangement carbanion DFT Medicinal chemistry dihydroacridines Analytical Chemistry chemistry.chemical_compound QD241-441 Deprotonation aryl substitution Drug Discovery potassium tert-butoxide QD Physical and Theoretical Chemistry Carbanion radical Grubbs–Stoltz reagent Chemistry Aryl Organic Chemistry electron transfer triethylsilane Chemistry (miscellaneous) Reagent Molecular Medicine Triethylsilane Methyl group |
| Zdroj: | Molecules Volume 26 Issue 22 Molecules, Vol 26, Iss 6879, p 6879 (2021) |
| ISSN: | 1420-3049 |
| DOI: | 10.3390/molecules26226879 |
| Popis: | Rearrangements of o-tolyl aryl ethers, amines, and sulfides with the Grubbs–Stoltz reagent (Et3SiH + KOtBu) were recently announced, in which the ethers were converted to o-hydroxydiarylmethanes, while the (o-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 o-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 Et3SiH/KOtBu system. |
| Databáze: | OpenAIRE |
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