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The Corey–Fuchs reaction, also known as the Ramirez–Corey–Fuchs reaction, is a series of
Article
) # Marshall, J. A.; Yanik, M. M.; Adams, N. D.; Ellis, K. C.; Chobanian, H. R. ''
Article
) # N. B. Desai, N. McKelvie, F. Ramirez '' JACS'', Vol. 84, p. 1745-1747 (1962).
Corey-Fuchs Alkyne Synthesis
{{DEFAULTSORT:Corey-Fuchs Reaction Carbon-carbon bond forming reactions Rearrangement reactions Name reactions
chemical reaction
A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the pos ...
s designed to transform an aldehyde
In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl grou ...
into an alkyne
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Acetylene
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Propyne
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1-Butyne
In organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond. The simplest acyclic alkynes with only one triple bond and n ...
. The formation of the 1,1-dibromoolefins via phosphine-dibromomethylenes was originally discovered by Desai, McKelvie and Ramirez. The second step of the reaction to convert dibromoolefins to alkynes is known as Fritsch–Buttenberg–Wiechell rearrangement
The Fritsch–Buttenberg–Wiechell rearrangement, named for Paul Ernst Moritz Fritsch (1859–1913), Wilhelm Paul Buttenberg, and Heinrich G. Wiechell, is a chemical reaction whereby a 1,1-diaryl-2-bromo-alkene rearranges to a 1,2-diaryl- alkyne ...
. The overall combined transformation of an aldehyde to an alkyne by this method is named after its developers, American chemists Elias James Corey
Elias James Corey (born July 12, 1928) is an American organic chemistry, organic chemist. In 1990, he won the Nobel Prize in Chemistry "for his development of the theory and methodology of organic synthesis", specifically retrosynthetic analysis. ...
and Philip L. Fuchs.
By suitable choice of base, it is often possible to stop the reaction at the 1-bromoalkyne, a useful functional group for further transformation.
Reaction mechanism
The Corey–Fuchs reaction is based on a special case of theWittig reaction
The Wittig reaction or Wittig olefination is a chemical reaction of an aldehyde or ketone with a triphenyl phosphonium ylide called a Wittig reagent. Wittig reactions are most commonly used to convert aldehydes and ketones to alkenes. Most o ...
, where two equivalents of triphenylphosphine are used with carbon tetrabromide
Tetrabromomethane, CBr4, also known as carbon tetrabromide, is a carbon bromide. Both names are acceptable under IUPAC nomenclature.
Physical properties
Tetrabromomethane has two polymorphs: crystalline II or β below 46.9 °C (320.0 ...
to produce the triphenylphosphine-dibromomethylene ylide.
This ylide undergoes a Wittig Reaction when exposed to an aldehyde. Alternatively, using a ketone generates a gem-dibromoalkene.
The second part of the reaction converts the isolable gem-dibromoalkene intermediate to the alkyne. Deuterium-labelling studies show that this step proceeds through a carbene mechanism. Lithium-Bromide exchange is followed by α-elimination to afford the carbene. 1,2-shift then affords the deuterium-labelled terminal alkyne. The 50% H-incorporation could be explained by deprotonation of the (acidic) terminal deuterium with excess BuLi.
See also
*Appel reaction
The Appel reaction is an organic reaction that converts an alcohol into an alkyl chloride using triphenylphosphine and carbon tetrachloride. The use of carbon tetrabromide or bromine as a halide source will yield alkyl bromides, whereas using carb ...
* Fritsch-Buttenberg-Wiechell rearrangement
* Seyferth-Gilbert homologation
*Wittig reaction
The Wittig reaction or Wittig olefination is a chemical reaction of an aldehyde or ketone with a triphenyl phosphonium ylide called a Wittig reagent. Wittig reactions are most commonly used to convert aldehydes and ketones to alkenes. Most o ...
References
# Corey, E. J.; Fuchs, P. L. ''Tetrahedron Lett.
''Tetrahedron Letters'' is a weekly international journal for rapid publication of full original research papers in the field of organic chemistry. According to the ''Journal Citation Reports'', the journal has a 2020 impact factor of 2.415.
Index ...
'' 1972, ''13'', 3769–3772.
# Mori, M.; Tonogaki, K.; Kinoshita, A. ''Organic Syntheses
''Organic Syntheses'' is a peer-reviewed scientific journal that was established in 1921. It publishes detailed and checked procedures for the synthesis of organic compounds. A unique feature of the review process is that all of the data and ex ...
'', Vol. 81, p. 1 (2005).Article
) # Marshall, J. A.; Yanik, M. M.; Adams, N. D.; Ellis, K. C.; Chobanian, H. R. ''
Organic Syntheses
''Organic Syntheses'' is a peer-reviewed scientific journal that was established in 1921. It publishes detailed and checked procedures for the synthesis of organic compounds. A unique feature of the review process is that all of the data and ex ...
'', Vol. 81, p. 157 (2005).Article
) # N. B. Desai, N. McKelvie, F. Ramirez '' JACS'', Vol. 84, p. 1745-1747 (1962).
External links
Corey-Fuchs Alkyne Synthesis
{{DEFAULTSORT:Corey-Fuchs Reaction Carbon-carbon bond forming reactions Rearrangement reactions Name reactions