Developing Efficient Nucleophilic Fluorination Methods and Application to Substituted Picolinate Esters
摘要:
This report describes nucleophilic fluorination of 3 and 5-substituted picolinate ester substrates using potassium fluoride in combination with additive promoters. Agents such as tributylmethylammonium or tetraphenylphosphonium chloride were among the best additives investigated giving improved fluorination yields. Additionally, the choice of additive promoters could influence the potential formation of new impurities such as alkyl ester exchange. Other parameters explored in this study include additive stoichiometry, temperature influence on additive degradation, solvent selection, product isolation by solvent extraction, and demonstration of additive recycling.
Mild Fluorination of Chloropyridines with in Situ Generated Anhydrous Tetrabutylammonium Fluoride
作者:Laura J. Allen、Joseck M. Muhuhi、Douglas C. Bland、Rachel Merzel、Melanie S. Sanford
DOI:10.1021/jo5003054
日期:2014.6.20
This paper describes the fluorination of nitrogen heterocycles usinganhydrous NBu4F. Quinoline derivatives as well as a number of 3- and 5-substituted pyridines undergo high-yielding fluorination at room temperature using this reagent. These results with anhydrous NBu4F compare favorably to traditional halex fluorinationsusing alkali metal fluorides, which generally require temperatures of ≥100 °C
[EN] PROCESS FOR FLUORINATING COMPOUNDS<br/>[FR] PROCÉDÉ DE FLUORATION DE COMPOSÉS
申请人:DOW AGROSCIENCES LLC
公开号:WO2017024167A1
公开(公告)日:2017-02-09
Disclosed are mild temperature (e.g., from 0 to 80°C) SNAr fluorinations of a variety of halide and sulfonate substituted aryl and heteroaryl substrates using NMe4F.
Nucleophilic Deoxyfluorination of Phenols via Aryl Fluorosulfonate Intermediates
作者:Sydonie D. Schimler、Megan A. Cismesia、Patrick S. Hanley、Robert D. J. Froese、Matthew J. Jansma、Douglas C. Bland、Melanie S. Sanford
DOI:10.1021/jacs.6b12911
日期:2017.2.1
This report describes a method for the deoxyfluorination of phenols with sulfuryl fluoride (SO2F2) and tetramethylammonium fluoride (NMe4F) via aryl fluorosulfonate (ArOFs) intermediates. We first demonstrate that the reaction of ArOFs with NMe4F proceeds under mild conditions (often at room temperature) to afford a broad range of electronically diverse and functional group-rich aryl fluoride products
Multiple Approaches to the In Situ Generation of Anhydrous Tetraalkylammonium Fluoride Salts for S<sub>N</sub>Ar Fluorination Reactions
作者:Megan A. Cismesia、Sarah J. Ryan、Douglas C. Bland、Melanie S. Sanford
DOI:10.1021/acs.joc.7b00481
日期:2017.5.19
focuses on the development of practical approaches to the in situ generation of anhydrous fluoride salts for applications in nucleophilic aromatic substitution (SNAr) reactions. We report herein that a variety of combinations of inexpensive nucleophiles (e.g., tetraalkylammonium cyanide and phenoxide salts) and fluorine-containing electrophiles (e.g., acid fluoride, fluoroformate, benzenesulfonyl fluoride
本文主要讨论的实际方法的原位生成无水氟化氢的盐的发展在亲核芳族取代(S应用Ñ AR)的反应。我们在此报告,廉价的亲核试剂(例如,四烷基氰化铵和酚盐)和含氟亲电试剂(例如,酰基氟,氟甲酸酯,苯磺酰氟和芳基氟磺酸酯衍生物)的多种组合对这种转化有效。最终,我们证明了2,6-二甲基苯氧基四甲基铵和硫酰氟(SO 2 F 2)的组合是制备无水四甲基氟化铵的一种特别实用的方法。此过程适用于S NAr氟化一系列电子不足的芳基和杂芳基氯化物以及硝基芳烃。
S<sub>N</sub>Ar Radiofluorination with In Situ Generated [<sup>18</sup>F]Tetramethylammonium Fluoride
作者:So Jeong Lee、María T. Morales-Colón、Allen F. Brooks、Jay S. Wright、Katarina J. Makaravage、Peter J. H. Scott、Melanie S. Sanford
DOI:10.1021/acs.joc.1c01491
日期:2021.10.15
describes a method for the nucleophilic radiofluorination of (hetero)aryl chlorides, (hetero)aryl triflates, and nitroarenes using a combination of [18F]KF·K2.2.2 and Me4NHCO3 for the in situ formation of a strongly nucleophilic fluorinating reagent (proposed to be [18F]Me4NF). This method is applied to 24 substrates bearing diverse functional groups, and it generates [18F](hetero)aryl fluoride products in