Definition of Finkelstein Reaction
The equilibrium position of the reaction depends on the nucleophilia of the anion, the presence of a good output group and the better stabilization of one anion in one solvent than in the other (see nucleophilic substitution). For example, reactions with KF lead to fluoroalkanes so neatly because fluoride is such a poor starting group due to the stability of the C-F bond. The Finkelstein reaction is another of the most important reactions in organic chemistry. It is used in the production of haloalkanes or alkyl halides. This is a substitutable bimolecular nucleophilic halogen exchange reaction (SN2 reaction). The asteroid is named after the German chemist Hans Finkelstein. It is an equilibrium reaction when performed without solvents. The completion of the reaction depends on the differential solubility of the halide salts in the polar aprotic solvent such as acetone. It is an organic reaction that uses an exchange of alkyl halides into another alkyl halide by a reaction in which the metal halide salt is used. This reaction takes place in an equilibrium process by taking advantage of the low solubility of acetone in the newly formed halide salt.
The mechanism of the Finkelstein reaction is a single-stage reaction (SN2 reaction) with stereochemical inversion. The reaction is named after the German chemist Hans Finkelstein, who published his work in a journal in 1910. This is Finkelstein Reaction, if you are also looking for study notes on other name reactions, register on Vedantu or download the Vedantu learning app. In the following, only a few applications of the Finkelstein reaction are listed – The equilibrium position of the reaction also depends on the solubility of the metal salt in the solvent used. Thus, the substitution of bromine and chloralkanes by AI in acetone leads properly to the desired iodalkane products, since KCl and KBr in acetone are insoluble and are therefore removed from equilibrium: The classic Finkelstein reaction involves the conversion of an alkyl chloride or an alkyl bromide to alkyl iodide by treatment with a solution of sodium iodide in acetone. Sodium iodide is soluble in acetone, sodium chloride and sodium bromide are not.  The reaction is caused by a mass action due to the precipitation of Poorly soluble NaCl or NaBr on the products. An example includes the conversion of the ethyl ester of 5-bromovalic acid to iodide: Alkyl halide (alkyl chloride or alkyl bromide) reacts with metalliodide in the presence of polar aprotic solvent such as acetone to obtain alkyl iodide and metal halide salt as precipitate.
This reaction is called the Finkelstein reaction. The Finkelstein reaction can be represented as follows – The synthesis of chrysochlamic acid is also carried out by Finkelstein reaction. The Finkelstein reaction is used in the production of alkyl halides using metal halides. This is an SN2 reaction in which one halogen atom is exchanged for another. In the reaction, newly formed metal halides such as sodium chloride and sodium bromide are not soluble in a polar aprotic solvent such as acetone. The reason for this is that the negative charge on the oxygen atom of acetone is repelled by the negative charge of cl and Br ions. As a result, insoluble metal halides precipitate and are continuously removed from the solution. The Finkelstein reaction is an equilibrium process driven by the use of the low solubility of these newly formed metal halide salts. Due to the SN2 reaction mechanism, a reversal of stereochemistry occurs [1-3].
As already mentioned, this is an equilibrium process, and the forward reaction is supported by the exploitation of the low solubility of the newly formed metal halide salt in acetone. The mechanism of this reaction is simple and direct. This is a bimolecular nucleophilic substitution reaction in a single step or SN2 reaction. Its mechanism is therefore the same as the SN2 reaction mechanism that occurs in the reversal of stereochemistry. The reaction mechanism is given below – The classical Finkelstein reaction involves the process of an alkyl bromide or alkyl chloride into an alkyl iodide treated with a solution of sodium iodide in acetone. Because sodium iodide is soluble in acetone, sodium bromide and sodium chloride are not soluble in acetone. The reaction works well with primary halides, but better with α-carbonyl halides and allylbenzene. The Finkelstein reaction is a bimolecular nucleophilic substitution reaction (SN2 reaction) in which halogen atoms are exchanged. It was named after the German chemist Hans Finkelstein.
The success of this reaction depends on the following conditions. Aromatic chlorides and bromides cannot be easily replaced by iodide, although they can occur if they are catalyzed accordingly. The “Finkelstein aromatic reaction” is catalyzed by copper(I) iodide in combination with diamine ligands.  Nickel bromide and tri-n-butylphosphine have also been shown to be suitable catalysts.  In the modern application of the Finkelstein reaction, it has expanded, including the conversion of alcohols to alkyl halides by converting alcohol to a sulfonate ester in the first step, and then substitution changes. Diamine ligands in copper-catalyzed reactionsDavid S. Surry and Stephen L. Buchwald, Chem. Sci., 2010, 1, 13DOI: 10.1039/c0sc00107d Alkyl halides differ significantly in the ease with which they undergo the Finkelstein reaction. The reaction works well for primary halides (except neoptentyl) and exceptionally well for allyl, benzyl and α-carbonyl halides. Secondary halides are much less reactive.
Vinyl, aryl and tertiary alkyl halides are not reactive; As a result, the reaction of NaI in acetone can be used as a qualitative test to determine which of the above classes belongs to an unknown alkyl halide, with the exception of alkylides, as they give the same product when substituted. Below certain relative reaction rates (NaI in acetone at 60 °C): Potassium fluoride is used for the conversion of chlorinated hydrocarbons to fluorocarbons.  Such reactions typically use polar solvents such as dimethylformamide, ethylene glycol and dimethyl sulfoxide.  If we take alkyl iodide instead of alkyl chloride or alkyl bromide and metal chloride or metal bromide instead of metalliodide, then the reaction does not take place for the following reason: The Finkelstein reaction named after the German chemist Hans Finkelstein is an SN2 reaction (bimolecular nucleophilic substitution), wherein one halogen atom is exchanged for another.