Favorskii reaction: Difference between revisions

Latest revision as of 11:13, 15 February 2025

Favorskii Reaction[edit]

Schematic representation of the Favorskii reaction.

The Favorskii reaction is an organic chemical reaction that involves the rearrangement of a cyclopropanone or an _-haloketone to form a carboxylic acid or its derivative. This reaction is named after the Russian chemist Aleksei Yevgrafovich Favorskii, who first reported it in the early 20th century.

Mechanism[edit]

The Favorskii reaction proceeds through a series of steps that involve the formation of an enolate intermediate. The general mechanism can be described as follows:

Formation of Enolate: The reaction begins with the deprotonation of the _-haloketone by a base, leading to the formation of an enolate ion.
Cyclopropanone Intermediate: The enolate undergoes an intramolecular nucleophilic attack on the carbon bearing the halogen, resulting in the formation of a cyclopropanone intermediate.
Ring Opening: The cyclopropanone ring opens to form a carbanion, which is stabilized by resonance.
Nucleophilic Attack: The carbanion then attacks a carbonyl carbon, leading to the formation of a new carbon-carbon bond.
Protonation: Finally, the intermediate is protonated to yield the carboxylic acid or its derivative.

Applications[edit]

The Favorskii reaction is widely used in organic synthesis for the preparation of cyclic and acyclic carboxylic acids. It is particularly useful in the synthesis of _-keto esters and _-lactones. The reaction is also employed in the synthesis of various natural products and pharmaceuticals.

Variations[edit]

Several variations of the Favorskii reaction have been developed to improve its efficiency and scope. These include the use of different bases, solvents, and reaction conditions to optimize the yield and selectivity of the desired product.

Related Reactions[edit]

The Favorskii reaction is related to other rearrangement reactions such as the Wolff rearrangement and the Arndt-Eistert synthesis, which also involve the formation and rearrangement of carbanion intermediates.

Related Pages[edit]

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-'''Favorskii Reaction'''
+{{DISPLAYTITLE:Favorskii Reaction}}
-The '''Favorskii Reaction''', named after the Russian chemist [[Aleksandr Favorskii]], is a pivotal chemical reaction in organic chemistry, involving the rearrangement of halo ketones in the presence of a base to form α-hydroxy ketones. This reaction is significant for its application in the synthesis of various complex organic compounds, including natural products and pharmaceuticals.
+== Favorskii Reaction ==
+[[File:Favorskii_Reaction.png|thumb|right|300px|Schematic representation of the Favorskii reaction.]]
+The '''Favorskii reaction''' is an organic chemical reaction that involves the rearrangement of a [[cyclopropanone]] or an _-haloketone to form a carboxylic acid or its derivative. This reaction is named after the Russian chemist [[Aleksei Yevgrafovich Favorskii]], who first reported it in the early 20th century.
-==Overview==
+== Mechanism ==
-The Favorskii Reaction typically involves the base-induced deprotonation of a halo ketone, which subsequently undergoes a rearrangement to form an α-hydroxy ketone. The mechanism can proceed via either a concerted process or through a carbenoid intermediate, depending on the nature of the substrate and the reaction conditions. The reaction is versatile, applicable to both aliphatic and aromatic substrates, and can be performed under a variety of conditions.
+The Favorskii reaction proceeds through a series of steps that involve the formation of an enolate intermediate. The general mechanism can be described as follows:
-==Mechanism==
+# '''Formation of Enolate:''' The reaction begins with the deprotonation of the _-haloketone by a base, leading to the formation of an enolate ion.
-The mechanism of the Favorskii Reaction begins with the deprotonation of the α-carbon adjacent to the carbonyl group in the halo ketone, forming a carbanion. This carbanion then attacks the halogen atom in an intramolecular fashion, leading to the formation of a cyclic intermediate. The intermediate can either directly rearrange to form the α-hydroxy ketone or proceed through a carbenoid intermediate, especially in the case of chloro and bromo ketones.
+# '''Cyclopropanone Intermediate:''' The enolate undergoes an intramolecular nucleophilic attack on the carbon bearing the halogen, resulting in the formation of a cyclopropanone intermediate.
+# '''Ring Opening:''' The cyclopropanone ring opens to form a carbanion, which is stabilized by resonance.
+# '''Nucleophilic Attack:''' The carbanion then attacks a carbonyl carbon, leading to the formation of a new carbon-carbon bond.
+# '''Protonation:''' Finally, the intermediate is protonated to yield the carboxylic acid or its derivative.
-==Variants==
+== Applications ==
-Several variants of the Favorskii Reaction exist, including the ''Preparative Favorskii Reaction'', which involves the use of strong bases, and the ''Non-classical Favorskii Reaction'', which employs milder conditions and can be used to synthesize cyclic compounds. The choice of variant often depends on the specific requirements of the synthesis, such as the sensitivity of the substrate to strong bases.
+The Favorskii reaction is widely used in organic synthesis for the preparation of cyclic and acyclic carboxylic acids. It is particularly useful in the synthesis of [[_-keto esters]] and [[_-lactones]]. The reaction is also employed in the synthesis of various natural products and pharmaceuticals.
-==Applications==
+== Variations ==
-The Favorskii Reaction finds widespread application in organic synthesis, particularly in the construction of complex molecular architectures. It is used in the synthesis of vitamins, hormones, and other biologically active compounds. Additionally, its ability to introduce hydroxyl groups adjacent to carbonyl groups makes it a valuable tool in the synthesis of natural products and pharmaceuticals.
+Several variations of the Favorskii reaction have been developed to improve its efficiency and scope. These include the use of different bases, solvents, and reaction conditions to optimize the yield and selectivity of the desired product.
-==Limitations==
+== Related Reactions ==
-Despite its versatility, the Favorskii Reaction has limitations. The reaction conditions, particularly the use of strong bases, can lead to side reactions or degradation of sensitive substrates. Moreover, the reaction's efficiency can be affected by the steric hindrance around the reaction center, limiting its applicability to certain substrates.
+The Favorskii reaction is related to other rearrangement reactions such as the [[Wolff rearrangement]] and the [[Arndt-Eistert synthesis]], which also involve the formation and rearrangement of carbanion intermediates.
-==See Also==
+== Related Pages ==
-* [[Haloform Reaction]]
+* [[Aleksei Yevgrafovich Favorskii]]
-* [[Aldol Reaction]]
+* [[Rearrangement reaction]]
-* [[Organic Synthesis]]
+* [[Cyclopropanone]]
-* [[Chemical Rearrangement]]
+* [[Carboxylic acid]]
+* [[Enolate]]
-==References==
-<references/>
 [[Category:Organic reactions]]
-[[Category:Name reactions]]
+[[Category:Rearrangement reactions]]
-[[Category:Chemical reactions]]
-{{Chemistry-stub}}