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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 .
Substitution reactions in organic chemistry are classified either as electrophilic or nucleophilic depending upon the reagent involved, whether a reactive intermediate involved in the reaction is a carbocation, a carbanion or a free radical, and whether the substrate is aliphatic or aromatic. Detailed understanding of a reaction type helps to ...
More recently, trifluoromethylation of diazonium salts has been developed and is referred to as a 'Sandmeyer-type' reaction. Diazonium salts also react with boronates, iodide, thiols, water, hypophosphorous acid and others, [6] and fluorination can be carried out using tetrafluoroborate anions (Balz–Schiemann reaction). However, since these ...
As mentioned above, aryl and alkenyl nonaflates are useful as electrophiles in palladium catalyzed cross coupling reactions. Their reactivity generally mirrors that of the more commonly encountered triflate electrophiles, but nonaflates tend to be less prone to hydrolysis to ketones (in the case of alkenyl sulfonates) and phenols (in the case of aryl sulfonates).
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 ...