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Nucleophilic Radiofluorination Using Tri-tert-Butanol Ammonium as a Bifunctional Organocatalyst: Mechanism and Energetics
We present a quantum chemical analysis of the (18)F-fluorination of 1,3-ditosylpropane, promoted by a quaternary ammonium salt (tri-(tert-butanol)-methylammonium iodide (TBMA-I) with moderate to good radiochemical yields (RCYs), experimentally observed by Shinde et al. We obtained the mechanism of t...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8838713/ https://www.ncbi.nlm.nih.gov/pubmed/35164308 http://dx.doi.org/10.3390/molecules27031044 |
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author | Oh, Young-Ho Shinde, Sandip S. Lee, Sungyul |
author_facet | Oh, Young-Ho Shinde, Sandip S. Lee, Sungyul |
author_sort | Oh, Young-Ho |
collection | PubMed |
description | We present a quantum chemical analysis of the (18)F-fluorination of 1,3-ditosylpropane, promoted by a quaternary ammonium salt (tri-(tert-butanol)-methylammonium iodide (TBMA-I) with moderate to good radiochemical yields (RCYs), experimentally observed by Shinde et al. We obtained the mechanism of the S(N)2 process, focusing on the role of the –OH functional groups facilitating the reactions. We found that the counter-cation TBMA(+) acts as a bifunctional promoter: the –OH groups function as a bidentate ‘anchor’ bridging the nucleophile [(18)F]F(−) and the –OTs leaving group or the third –OH. These electrostatic interactions cooperate for the formation of the transition states of a very compact configuration for facile S(N)2 (18)F-fluorination. |
format | Online Article Text |
id | pubmed-8838713 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-88387132022-02-13 Nucleophilic Radiofluorination Using Tri-tert-Butanol Ammonium as a Bifunctional Organocatalyst: Mechanism and Energetics Oh, Young-Ho Shinde, Sandip S. Lee, Sungyul Molecules Article We present a quantum chemical analysis of the (18)F-fluorination of 1,3-ditosylpropane, promoted by a quaternary ammonium salt (tri-(tert-butanol)-methylammonium iodide (TBMA-I) with moderate to good radiochemical yields (RCYs), experimentally observed by Shinde et al. We obtained the mechanism of the S(N)2 process, focusing on the role of the –OH functional groups facilitating the reactions. We found that the counter-cation TBMA(+) acts as a bifunctional promoter: the –OH groups function as a bidentate ‘anchor’ bridging the nucleophile [(18)F]F(−) and the –OTs leaving group or the third –OH. These electrostatic interactions cooperate for the formation of the transition states of a very compact configuration for facile S(N)2 (18)F-fluorination. MDPI 2022-02-03 /pmc/articles/PMC8838713/ /pubmed/35164308 http://dx.doi.org/10.3390/molecules27031044 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Oh, Young-Ho Shinde, Sandip S. Lee, Sungyul Nucleophilic Radiofluorination Using Tri-tert-Butanol Ammonium as a Bifunctional Organocatalyst: Mechanism and Energetics |
title | Nucleophilic Radiofluorination Using Tri-tert-Butanol Ammonium as a Bifunctional Organocatalyst: Mechanism and Energetics |
title_full | Nucleophilic Radiofluorination Using Tri-tert-Butanol Ammonium as a Bifunctional Organocatalyst: Mechanism and Energetics |
title_fullStr | Nucleophilic Radiofluorination Using Tri-tert-Butanol Ammonium as a Bifunctional Organocatalyst: Mechanism and Energetics |
title_full_unstemmed | Nucleophilic Radiofluorination Using Tri-tert-Butanol Ammonium as a Bifunctional Organocatalyst: Mechanism and Energetics |
title_short | Nucleophilic Radiofluorination Using Tri-tert-Butanol Ammonium as a Bifunctional Organocatalyst: Mechanism and Energetics |
title_sort | nucleophilic radiofluorination using tri-tert-butanol ammonium as a bifunctional organocatalyst: mechanism and energetics |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8838713/ https://www.ncbi.nlm.nih.gov/pubmed/35164308 http://dx.doi.org/10.3390/molecules27031044 |
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