Academic Journal
TMSCF 3 ‑Mediated Conversion of Salicylates into α,α-Difluoro-3-coumaranones: Chain Kinetics, Anion-Speciation, and Mechanism
| العنوان: | TMSCF 3 ‑Mediated Conversion of Salicylates into α,α-Difluoro-3-coumaranones: Chain Kinetics, Anion-Speciation, and Mechanism |
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| المؤلفون: | Hannah B. Minshull, Guy C. Lloyd-Jones |
| سنة النشر: | 2023 |
| مصطلحات موضوعية: | Biophysics, Biochemistry, Medicine, Genetics, Molecular Biology, Immunology, Developmental Biology, Inorganic Chemistry, Infectious Diseases, Plant Biology, Computational Biology, Biological Sciences not elsewhere classified, Chemical Sciences not elsewhere classified, tbat ([ ph, five distinct stages, first three stages, >- silylated derivatives, transfer chain reactions, thf generates α, si nmr spectroscopy, >- silylated salicylate, 4 , 29 , 19 , 3 , slow liberation, rapidly accelerated, overall viability, kinetic model, initial concentrations |
| الوصف: | As reported by Zhao, the TBAT ([Ph 3 SiF 2 ] − [Bu 4 N] + )-initiated reaction of ethyl salicylate with TMSCF 3 in THF generates α,α-difluoro-3-coumaranones via the corresponding O -silylated ethoxy ketals. The mechanism has been investigated by in situ 19 F and 29 Si NMR spectroscopy, CF 2 -trapping, competition, titration, and comparison of the kinetics with the 3-, 4-, 5-, and 6-fluoro ethyl salicylate analogues and their O -silylated derivatives. The process evolves in five distinct stages, each arising from a discrete array of anion speciations that modulate a sequence of silyl-transfer chain reactions. The deconvolution of coupled equilibria between salicylate, [CF 3 ] − , and siliconate [Me 3 Si(CF 3 ) 2 ] − anions allowed the development of a kinetic model that accounts for the first three stages. The model provides valuable practical insights. For example, it explains how the initial concentrations of the TMSCF 3 and salicylate and the location of electron-withdrawing salicylate ring substituents profoundly impact the overall viability of the process, how stoichiometric CF 3 H generation can be bypassed by using the O -silylated salicylate, and how the very slow liberation of the α,α-difluoro-3-coumaranone can be rapidly accelerated by evaporative or aqueous workup. |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | unknown |
| Relation: | https://figshare.com/articles/journal_contribution/TMSCF_sub_3_sub_Mediated_Conversion_of_Salicylates_into_-Difluoro-3-coumaranones_Chain_Kinetics_Anion-Speciation_and_Mechanism/24716132 |
| DOI: | 10.1021/acs.joc.3c02219.s001 |
| الاتاحة: | https://doi.org/10.1021/acs.joc.3c02219.s001 https://figshare.com/articles/journal_contribution/TMSCF_sub_3_sub_Mediated_Conversion_of_Salicylates_into_-Difluoro-3-coumaranones_Chain_Kinetics_Anion-Speciation_and_Mechanism/24716132 |
| Rights: | CC BY-NC 4.0 |
| رقم الانضمام: | edsbas.BD659BF8 |
| قاعدة البيانات: | BASE |
| DOI: | 10.1021/acs.joc.3c02219.s001 |
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