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The mechanism of electrophilic fluorination remains controversial. At issue is whether the reaction proceeds via an S N 2 or single-electron transfer (SET) process. In support of the S N 2 mechanism, aryl Grignard reagents and aryllithiums give similar yields of fluorobenzene in combination with N-fluoro-o-benzenedisulfonimide (NFOBS), even though the tendencies of these reagents to ...
Electrophilic fluorinating reagents could in principle operate by electron transfer pathways or an S N 2 attack at fluorine. This distinction has not been decided. [2] By using a charge-spin separated probe, [3] it was possible to show that the electrophilic fluorination of stilbenes with Selectfluor proceeds through an SET/fluorine atom transfer mechanism.
Starting in the late 1940s, a series of electrophilic fluorinating methodologies were introduced, beginning with CoF 3. Electrochemical fluorination ("electrofluorination") was announced, which Joseph H. Simons had developed in the 1930s to generate highly stable perfluorinated materials compatible with uranium hexafluoride. [15]
Electrochemical fluorination (ECF), or electrofluorination, is a foundational organofluorine chemistry method for the preparation of fluorocarbon-based organofluorine compounds. [1] The general approach represents an application of electrosynthesis .
Mild fluorination of polyethylene gives does not make all of the plastic lose its hydrogens for fluorine; only a thin layer (0.01 mm at maximum) is then affected. This is somewhat similar to metal passivation: the bulk properties are not affected, but the surface properties are, most notably, a greater vapor barrier. Therefore, they are a ...
The lithium enolates of methyl ketones give mixtures of products derived from electrophilic attack on the O (expected) or C (unexpected) atoms of the enolate. This effect is particularly evident with the lithium enolate of pinacolone, which gives a 2:1 mixture favoring C-attack.
Aromatic compounds are subject to electrophilic halogenation: R−C 6 H 5 + X 2 → HX + R−C 6 H 4 −X. This kind of reaction typically works well for chlorine and bromine. Often a Lewis acidic catalyst is used, such as ferric chloride. [7] Many detailed procedures are available.
Selectfluor, a fluorination agent, and other N–F electrophilic fluorine sources. Bromonium and iodonium species, including py 2 X + (X = Br; X = I: Barluenga's reagent) and Ar 2 I + (diaryliodonium salts) Silver tetrafluoroborate and thallium tetrafluoroborate [6] are convenient halide abstracting agents (although the thallium salt is highly ...