Wurtz–Fittig reaction

Last updated

Contents

Wurtz–Fittig reaction
Named after Charles Adolphe Wurtz
Wilhelm Rudolph Fittig
Reaction type Coupling reaction
Identifiers
Organic Chemistry Portal wurtz-fittig-reaction

The Wurtz–Fittig reaction is the chemical reaction of an aryl halide, alkyl halides, and sodium metal to give substituted aromatic compounds. [1] Following the work of Charles Adolphe Wurtz on the sodium-induced coupling of alkyl halides (the Wurtz reaction), Wilhelm Rudolph Fittig extended the approach to the coupling of an alkyl halide with an aryl halide. [2] [3] This modification of the Wurtz reaction is considered a separate process and is named for both scientists. [1]

Wurtz-Fittig synthesis.svg

The reaction works best for forming asymmetrical products if the halide reactants are somehow separate in their relative chemical reactivities. One way to accomplish this is to form the reactants with halogens of different periods. Typically the alkyl halide is made more reactive than the aryl halide, increasing the probability that the alkyl halide will form the organosodium bond first and thus act more effectively as a nucleophile toward the aryl halide. [4] Typically the reaction is used for the alkylation of aryl halides. With the use of ultrasound sodium reacts with some aryl halides to produce biphenyl compounds. [5]

Mechanism

The mechanism of the Wurtz–Fittig reaction has not been the subject of modern investigations. The process was once proposed to involve the combination of an alkyl and aryl radicals. [6] [7] Another mechanistic proposal invoked the generation of organosodium intermediates. [8] The reaction of sodium and chlorobenzene produces triphenylene, which supports a role for radicals. [8] A role for organosodium compounds is supported by indirect evidence. [7] [6] For example, addition of carbon dioxide to a mixture of sodium and isobutyl bromide results in the formation of 3-methylbutanoic acid after acid workup. [9] [10]

Use of other metals

The Wurtz–Fittig reaction can be conducted using metals other than sodium. Some examples include potassium, iron, copper, and lithium. [11] When lithium is used, the reaction occurs with appreciable yield only under ultrasound. [12] Ultrasound is known to cleave halogen atoms from aryl and alkyl halides through a free-radical mechanism [13]

Applications

The Wurtz–Fittig reaction has limited applicability, because it is plagued by side reactions including rearrangements and eliminations. [11] The reaction has been applied to the laboratory synthesis of some organosilicon compounds. [14] One example is the conversion of tetraethyl orthosilicate to the mono-tert-butoxy derivative in 40% yield as summarized in this idealized equation: [15]

Si(OC2H5)4 + 2 Na + (CH3)3CCl → Si(OC2H5)3OC(CH3)3 + NaCl + C2H5ONa

Molten sodium was used.

Other organosilicon compounds synthesized using the Wurtz–Fittig reaction include silylated calixarenes [16] and vinylsilanes. [17]

See also

Related Research Articles

<span class="mw-page-title-main">Haloalkane</span> Group of chemical compounds derived from alkanes containing one or more halogens

The haloalkanes are alkanes containing one or more halogen substituents. They are a subset of the general class of halocarbons, although the distinction is not often made. Haloalkanes are widely used commercially. They are used as flame retardants, fire extinguishants, refrigerants, propellants, solvents, and pharmaceuticals. Subsequent to the widespread use in commerce, many halocarbons have also been shown to be serious pollutants and toxins. For example, the chlorofluorocarbons have been shown to lead to ozone depletion. Methyl bromide is a controversial fumigant. Only haloalkanes that contain chlorine, bromine, and iodine are a threat to the ozone layer, but fluorinated volatile haloalkanes in theory may have activity as greenhouse gases. Methyl iodide, a naturally occurring substance, however, does not have ozone-depleting properties and the United States Environmental Protection Agency has designated the compound a non-ozone layer depleter. For more information, see Halomethane. Haloalkane or alkyl halides are the compounds which have the general formula "RX" where R is an alkyl or substituted alkyl group and X is a halogen.

In organic chemistry, an aryl halide is an aromatic compound in which one or more hydrogen atoms, directly bonded to an aromatic ring are replaced by a halide. The haloarene are different from haloalkanes because they exhibit many differences in methods of preparation and properties. The most important members are the aryl chlorides, but the class of compounds is so broad that there are many derivatives and applications.

In organic chemistry, the Wurtz reaction, named after Charles Adolphe Wurtz, is a coupling reaction whereby two alkyl halides are treated with sodium metal to form a higher alkane.

The Sandmeyer reaction is a chemical reaction used to synthesize aryl halides from aryl diazonium salts using copper salts as reagents or catalysts. It is an example of a radical-nucleophilic aromatic substitution. The Sandmeyer reaction provides a method through which one can perform unique transformations on benzene, such as halogenation, cyanation, trifluoromethylation, and hydroxylation.

Metalation is a chemical reaction that forms a bond to a metal. This reaction usually refers to the replacement of a halogen atom in an organic molecule with a metal atom, resulting in an organometallic compound. In the laboratory, metalation is commonly used to activate organic molecules during the formation of C—X bonds, which are necessary for the synthesis of many organic molecules.

The Hiyama coupling is a palladium-catalyzed cross-coupling reaction of organosilanes with organic halides used in organic chemistry to form carbon–carbon bonds. This reaction was discovered in 1988 by Tamejiro Hiyama and Yasuo Hatanaka as a method to form carbon-carbon bonds synthetically with chemo- and regioselectivity. The Hiyama coupling has been applied to the synthesis of various natural products.

The Corey–House synthesis (also called the Corey–Posner–Whitesides–House reaction and other permutations) is an organic reaction that involves the reaction of a lithium diorganylcuprate () with an organic halide or pseudohalide () to form a new alkane, as well as an ill-defined organocopper species and lithium (pseudo)halide as byproducts.

The Ullmann reaction or Ullmann coupling is a coupling reaction between aryl halides. Traditionally this reaction is effected by copper, but palladium and nickel are also effective catalysts. The reaction is named after Fritz Ullmann.

<span class="mw-page-title-main">Wilhelm Rudolph Fittig</span> German chemist (1835–1910)

Wilhelm Rudolph Fittig was a German chemist. He discovered the pinacol coupling reaction, mesitylene, diacetyl and biphenyl. Fittig studied the action of sodium on ketones and hydrocarbons. He discovered the Fittig reaction or Wurtz–Fittig reaction for the synthesis of alkylbenzenes, he proposed a diketone structure for benzoquinone and isolated phenanthrene from coal tar. He discovered and synthesized the first lactones and investigated structures of piperine, naphthalene, and fluorene.

<span class="mw-page-title-main">Favorskii rearrangement</span> Chemical reaction

The Favorskii rearrangement is principally a rearrangement of cyclopropanones and α-halo ketones that leads to carboxylic acid derivatives. In the case of cyclic α-halo ketones, the Favorskii rearrangement constitutes a ring contraction. This rearrangement takes place in the presence of a base, sometimes hydroxide, to yield a carboxylic acid but most of the time either an alkoxide base or an amine to yield an ester or an amide, respectively. α,α'-Dihaloketones eliminate HX under the reaction conditions to give α,β-unsaturated carbonyl compounds.

The Finkelstein reaction, named after the German chemist Hans Finkelstein, is an SN2 reaction that involves the exchange of one halogen atom for another. It is an equilibrium reaction, but the reaction can be driven to completion by exploiting the differential solubility of halide salts, or by using a large excess of the halide salt.

The Negishi coupling is a widely employed transition metal catalyzed cross-coupling reaction. The reaction couples organic halides or triflates with organozinc compounds, forming carbon-carbon bonds (C-C) in the process. A palladium (0) species is generally utilized as the metal catalyst, though nickel is sometimes used. A variety of nickel catalysts in either Ni0 or NiII oxidation state can be employed in Negishi cross couplings such as Ni(PPh3)4, Ni(acac)2, Ni(COD)2 etc.

<span class="mw-page-title-main">Organozinc chemistry</span>

Organozinc chemistry is the study of the physical properties, synthesis, and reactions of organozinc compounds, which are organometallic compounds that contain carbon (C) to zinc (Zn) chemical bonds.

The Riemschneider thiocarbamate synthesis converts alkyl or aryl thiocyanates to thiocarbamates under acidic conditions, followed by hydrolysis with ice water. The reaction was discovered by the German chemist Randolph Riemschneider in 1951 as a more efficient method to produce thiocarbamates. Some references spell the name Riemenschneider.

Organosodium chemistry is the chemistry of organometallic compounds containing a carbon to sodium chemical bond. The application of organosodium compounds in chemistry is limited in part due to competition from organolithium compounds, which are commercially available and exhibit more convenient reactivity.

<span class="mw-page-title-main">Phenylsodium</span> Chemical compound

Phenylsodium C6H5Na is an organosodium compound. Solid phenylsodium was first isolated by Nef in 1903. Although the behavior of phenylsodium and phenyl magnesium bromide are similar, the organosodium compound is very rarely used.

In organic chemistry, alkynylation is an addition reaction in which a terminal alkyne is added to a carbonyl group to form an α-alkynyl alcohol.

Cross electrophile coupling is a type of cross-coupling reaction that occurs between two electrophiles often catalyzed by transition metal catalyst(s). Unlike conventional cross-coupling reactions of an electrophile with an organometallic reagent, the coupling partners in cross electrophile coupling reactions are both electrophiles. Generally, additional reductant to regenerate active catalyst is needed in this reaction.

Transhalogenation is a substitution reaction in which the halide of a halide compound is exchanged for another halide.

In organometallic chemistry, metal–halogen exchange is a fundamental reaction that converts an organic halide into an organometallic product. The reaction commonly involves the use of electropositive metals and organochlorides, bromides, and iodides. Particularly well-developed is the use of metal–halogen exchange for the preparation of organolithium compounds.

References

  1. 1 2 Wang, Zerong (2010). "Wurtz–Fittig Reaction". Comprehensive Organic Name Reactions and Reagents. Vol. 686. pp. 3100–3104. doi:10.1002/9780470638859.conrr686. ISBN   9780470638859.
  2. ↑ Tollens, Bernhard; Rudolph Fittig (1864). "Ueber die Synthese der Kohlenwasserstoffe der Benzolreihe" [On the synthesis of the hydrocarbons of the benzene series]. Justus Liebigs Annalen der Chemie (in German). 131 (3): 303–323. doi:10.1002/jlac.18641310307.
  3. ↑ Fittig, Rudolph; König, Joseph (1867). "Ueber das Aethyl- und Diäthylbenzol" [About ethyl- and diethylbenzene]. Justus Liebigs Annalen der Chemie (in German). 144 (3): 277–294. doi:10.1002/jlac.18671440308.
  4. ↑ Desai, K. R. (2008). Organic Name Reactions . Jaipur, India: Oxford Book Company. p.  https://archive.org/details/handbookinorgani00desa/page/n267 259]. ISBN   9788189473327.
  5. ↑ Laue, Thomas; Plagens, Andreas (2005). Named Organic Reactions (2nd ed.). Wolfsburg, Germany: John Wiley & Sons. p.  305. ISBN   9780470010402.
  6. 1 2 Wooster, Charles Bushnell (1932). "Organo-alkali Compounds". Chemical Reviews . 11 (1): 1–91. doi:10.1021/cr60038a001. ISSN   0009-2665.
  7. 1 2 Gilman, Henry; Wright, George F. (1933). "The Mechanism of the Wurtz—Fittig Reaction. The Direct Preparation of an Organosodium (Potassium) Compound from an RX Compound". Journal of the American Chemical Society . 55 (7): 2893–2896. doi:10.1021/ja01334a044. ISSN   0002-7863.
  8. 1 2 Bachmann, W. E.; Clarke, H. T. (1927). "The Mechanism of the Wurtz–Fittig Reaction". Journal of the American Chemical Society . 49 (8): 2089–2098. doi:10.1021/ja01407a038. ISSN   0002-7863.
  9. ↑ Schorigin, Paul (1908). "Synthesen mittels Natrium und Halogenalkylen". Berichte der Deutschen Chemischen Gesellschaft. 41 (2): 2711–2717. doi:10.1002/cber.190804102208.
  10. ↑ Schorigin, Paul (1910). "Über die Natriumalkyle und über ihre Reaktion mit den Äthern". Berichte der Deutschen Chemischen Gesellschaft. 43 (2): 1931–1938. doi:10.1002/cber.191004302128.
  11. 1 2 Smith, Michael; March, Jerry (2007). March's advanced organic chemistry: Reactions, mechanisms, and structure (6th ed.). Hoboken, N.J.: Wiley-Interscience. ISBN   978-0471720911. OCLC   69020965.
  12. ↑ Han, Byung Hee; Boudjouk, Philip (1981). "Organic sonochemistry. Ultrasound-promoted coupling of organic halides in the presence of lithium wire". Tetrahedron Letters . 22 (29): 2757–2758. doi:10.1016/S0040-4039(01)90544-1. ISSN   0040-4039.
  13. ↑ Prakash, S.; Pandey, J. D. (1965). "Sonocleavage of halogens from aliphatic chains and aromatic rings". Tetrahedron . 21 (4): 903–908. doi:10.1016/0040-4020(65)80026-6. ISSN   0040-4020.
  14. ↑ Bassett, E. A.; Emblem, H. G.; Frankel, M.; Ridge, D. (1948). "The use of the Wurtz–Fittig reaction in the preparation of organo-substituted silanes". Journal of the Society of Chemical Industry . 67 (5): 177–179. doi:10.1002/jctb.5000670503. ISSN   0368-4075.
  15. ↑ Chappelow, C. C.; Elliott, R. L.; Goodwin, J. T. (1962). "Synthesis of t-Butylsilicon Compounds by the Wurtz–Fitting Reaction". The Journal of Organic Chemistry . 27 (4): 1409–1414. doi:10.1021/jo01051a069. ISSN   0022-3263.
  16. ↑ Hudrlik, Paul F.; Arasho, Wondwossen D.; Hudrlik, Anne M. (2007). "The Wurtz–Fittig Reaction in the Preparation of C-Silylated Calixarenes". The Journal of Organic Chemistry . 72 (21): 8107–8110. doi:10.1021/jo070660n. ISSN   0022-3263. PMID   17850095.
  17. ↑ Adam, Waldemar; Richter, Markus J. (1994). "One-Pot Synthesis of α-Trimethylsilyl Enones from Vinylsilanes". Synthesis . 1994 (2): 176–180. doi:10.1055/s-1994-25433. ISSN   0039-7881.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.