The Wurtz–Fittig reaction is the chemical reaction of aryl halides with alkyl halides and sodium metal in the presence of dry ether to give substituted aromatic compounds.[1]Charles Adolphe Wurtz reported what is now known as the Wurtz reaction in 1855,[2][3] involving the formation of a new carbon-carbon bond by coupling two alkyl halides.[4][5] Work by Wilhelm Rudolph Fittig in the 1860s extended the approach to the coupling of an alkyl halide with an aryl halide.[6][7] This modification of the Wurtz reaction is considered a separate process and is named for both scientists.[1]
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.[8] Typically the reaction is used for the alkylation of aryl halides; however, with the use of ultrasound the reaction can also be made useful for the production of biphenyl compounds.[9]
There are two approaches to describing the mechanism of the Wurtz–Fittig reaction.[10][11] The first involves the sodium-mediated formation of both alkyl and aryl radicals. The alkyl and aryl radicals then combine to form a substituted aromatic compound.
Radical Mechanism for the Wurtz–Fittig Reaction
The second approach involves the formation of an intermediate organo-alkali compound followed by nucleophilic attack of the alkyl halide.
Organo-alkali Mechanism of the Wurtz–Fittig Reaction
There is empirical evidence for both approaches. The free radical mechanism is supported by the observation of side products whose formation cannot be explained by an organo-alkali mechanism.[12] In a reaction between sodium and chlorobenzene, Bachmann and Clarke[12] find that one of the many side products is triphenylene. They contend that the only way to explain the formation of triphenylene is through a free radical mechanism. In this mechanism, two free phenyl radicals react to form benzene and a free phenylene anion. The three phenylene anions then combine via a radical mechanism to form the triphenylene molecule. Bachmann and Clarke[12] consider the occurrence of triphenylene as evidence that the Wurtz–Fittig reaction happens through a radical mechanism.
The organo-alkali mechanism is supported by indirect evidence which shows that an organo-alkali intermediate actually forms during the reaction.[11] This has been observed my many investigators.[10] For example, Shoruguin[13] shows that carbon dioxide bubbling through a mixture of sodium and isobutyl bromide results in the formation of 3-methylbutanoic acid.
Reaction Scheme for the Formation of 3-methylbutanoic acid
The formation of 3-methylbutanoic acid follows from a nucleophilic attack of carbon dioxide by an organosodium compound. These results suggest that Wurtz–Fittig reaction occurs via the formation of an organoalkali compound since the reaction conditions are similar.
Use of other metals
The Wurtz–Fittig reaction can be conducted using metals other than sodium. Some examples include potassium, iron, copper, and lithium.[14] When lithium is used, the reaction occurs with appreciable yield only under ultrasound.[15] Ultrasound is known to cleave halogen atoms from aryl and alkyl halides through a free-radical mechanism[16]
Applications
The Wurtz–Fittig reaction has limited applicability, since side reactions such as rearrangements and eliminations are prevalent.[14] However, the reaction is useful for the laboratory synthesis of organosilicon compounds, although there are challenges in adapting the procedure to a large-scale industrial process.[17] Organosilicon compounds successfully synthesized using the Wurtz–Fittig reaction include silylated calixarenes,[18]t-butylsilicon compounds,[19] and vinylsilanes.[20] For example, t-butyltriethoxysilane can be prepared with the Wurtz–Fitting reaction by combining tetraoxysilane, t-butyl chloride and molten sodium. The reaction proceeds with a 40% yield.[19]
The synthesis of t-butyltriethoxysilane by the Wurtz–Fittig reaction
^Wurtz, A. (1855). "Ueber eine neue Klasse organischer Radicale" [About a new class of organic radicals]. Justus Liebigs Annalen der Chemie (in German). 96 (3): 364–375. doi:10.1002/jlac.18550960310.
^Wang, Zerong (2010). "Wurtz Synthesis (Wurtz Reaction, Wurtz Reductive Coupling)". Comprehensive Organic Name Reactions and Reagents. Vol. 685. pp. 3094–3099. doi:10.1002/9780470638859.conrr685. ISBN9780470638859.
^Kantchev, Eric Asssen B.; Organ, Michael G. (2014). "48.1.2.4 Method 4: Reductive Coupling of Alkyl Halides". In Hiemstra, H. (ed.). Alkanes. Science of Synthesis: Houben-Weyl Methods of Molecular Transformations. Vol. 48. Georg Thieme Verlag. ISBN9783131784810.
^Laue, Thomas; Plagens, Andreas (2005). Named Organic Reactions (2nd ed.). Wolfsburg, Germany: John Wiley & Sons. p. 305. ISBN9780470010402.
^ abWooster, Charles Bushnell (1932). "Organo-alkali Compounds". Chemical Reviews. 11 (1): 1–91. doi:10.1021/cr60038a001. ISSN 0009-2665.
^ abGilman, 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.
^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.
^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.
^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.
^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.
^ abChappelow, 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.
^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.
wurtz, fittig, reaction, chemical, reaction, aryl, halides, with, alkyl, halides, sodium, metal, presence, ether, give, substituted, aromatic, compounds, charles, adolphe, wurtz, reported, what, known, wurtz, reaction, 1855, involving, formation, carbon, carbo. The Wurtz Fittig reaction is the chemical reaction of aryl halides with alkyl halides and sodium metal in the presence of dry ether to give substituted aromatic compounds 1 Charles Adolphe Wurtz reported what is now known as the Wurtz reaction in 1855 2 3 involving the formation of a new carbon carbon bond by coupling two alkyl halides 4 5 Work by Wilhelm Rudolph Fittig in the 1860s extended the approach to the coupling of an alkyl halide with an aryl halide 6 7 This modification of the Wurtz reaction is considered a separate process and is named for both scientists 1 Wurtz Fittig reactionNamed after Charles Adolphe Wurtz Wilhelm Rudolph FittigReaction type Coupling reactionIdentifiersOrganic Chemistry Portal wurtz fittig reaction 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 8 Typically the reaction is used for the alkylation of aryl halides however with the use of ultrasound the reaction can also be made useful for the production of biphenyl compounds 9 Contents 1 Mechanism 2 Use of other metals 3 Applications 4 See also 5 ReferencesMechanism EditThere are two approaches to describing the mechanism of the Wurtz Fittig reaction 10 11 The first involves the sodium mediated formation of both alkyl and aryl radicals The alkyl and aryl radicals then combine to form a substituted aromatic compound Radical Mechanism for the Wurtz Fittig Reaction The second approach involves the formation of an intermediate organo alkali compound followed by nucleophilic attack of the alkyl halide Organo alkali Mechanism of the Wurtz Fittig Reaction There is empirical evidence for both approaches The free radical mechanism is supported by the observation of side products whose formation cannot be explained by an organo alkali mechanism 12 In a reaction between sodium and chlorobenzene Bachmann and Clarke 12 find that one of the many side products is triphenylene They contend that the only way to explain the formation of triphenylene is through a free radical mechanism In this mechanism two free phenyl radicals react to form benzene and a free phenylene anion The three phenylene anions then combine via a radical mechanism to form the triphenylene molecule Bachmann and Clarke 12 consider the occurrence of triphenylene as evidence that the Wurtz Fittig reaction happens through a radical mechanism The organo alkali mechanism is supported by indirect evidence which shows that an organo alkali intermediate actually forms during the reaction 11 This has been observed my many investigators 10 For example Shoruguin 13 shows that carbon dioxide bubbling through a mixture of sodium and isobutyl bromide results in the formation of 3 methylbutanoic acid Reaction Scheme for the Formation of 3 methylbutanoic acid The formation of 3 methylbutanoic acid follows from a nucleophilic attack of carbon dioxide by an organosodium compound These results suggest that Wurtz Fittig reaction occurs via the formation of an organoalkali compound since the reaction conditions are similar Use of other metals EditThe Wurtz Fittig reaction can be conducted using metals other than sodium Some examples include potassium iron copper and lithium 14 When lithium is used the reaction occurs with appreciable yield only under ultrasound 15 Ultrasound is known to cleave halogen atoms from aryl and alkyl halides through a free radical mechanism 16 Applications EditThe Wurtz Fittig reaction has limited applicability since side reactions such as rearrangements and eliminations are prevalent 14 However the reaction is useful for the laboratory synthesis of organosilicon compounds although there are challenges in adapting the procedure to a large scale industrial process 17 Organosilicon compounds successfully synthesized using the Wurtz Fittig reaction include silylated calixarenes 18 t butylsilicon compounds 19 and vinylsilanes 20 For example t butyltriethoxysilane can be prepared with the Wurtz Fitting reaction by combining tetraoxysilane t butyl chloride and molten sodium The reaction proceeds with a 40 yield 19 The synthesis of t butyltriethoxysilane by the Wurtz Fittig reactionSee also EditWurtz reactionReferences Edit a b Wang Zerong 2010 Wurtz Fittig Reaction Comprehensive Organic Name Reactions and Reagents Vol 686 pp 3100 3104 doi 10 1002 9780470638859 conrr686 ISBN 9780470638859 Wurtz Adolphe 1855 Sur une Nouvelle Classe de Radicaux Organiques On a New Class of Organic Radicals Annales de Chimie et de Physique in French 44 275 312 Wurtz A 1855 Ueber eine neue Klasse organischer Radicale About a new class of organic radicals Justus Liebigs Annalen der Chemie in German 96 3 364 375 doi 10 1002 jlac 18550960310 Wang Zerong 2010 Wurtz Synthesis Wurtz Reaction Wurtz Reductive Coupling Comprehensive Organic Name Reactions and Reagents Vol 685 pp 3094 3099 doi 10 1002 9780470638859 conrr685 ISBN 9780470638859 Kantchev Eric Asssen B Organ Michael G 2014 48 1 2 4 Method 4 Reductive Coupling of Alkyl Halides In Hiemstra H ed Alkanes Science of Synthesis Houben Weyl Methods of Molecular Transformations Vol 48 Georg Thieme Verlag ISBN 9783131784810 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 Fittig Rudolph Konig Joseph 1867 Ueber das Aethyl und Diathylbenzol About ethyl and diethylbenzene Justus Liebigs Annalen der Chemie in German 144 3 277 294 doi 10 1002 jlac 18671440308 Desai K R 2008 Organic Name Reactions Jaipur India Oxford Book Company p https archive org details handbookinorgani00desa page n267 259 ISBN 9788189473327 Laue Thomas Plagens Andreas 2005 Named Organic Reactions 2nd ed Wolfsburg Germany John Wiley amp Sons p 305 ISBN 9780470010402 a b Wooster Charles Bushnell 1932 Organo alkali Compounds Chemical Reviews 11 1 1 91 doi 10 1021 cr60038a001 ISSN 0009 2665 a b 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 a b c 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 Schoruigin Ber 41 2711 7 1908 ibid 43 1938 42 1910 a b 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 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 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 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 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 a b 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 Adam Waldemar Richter Markus J 1994 One Pot Synthesis of a Trimethylsilyl Enones from Vinylsilanes Synthesis 1994 2 176 180 doi 10 1055 s 1994 25433 ISSN 0039 7881 This chemical reaction article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Wurtz Fittig reaction amp oldid 1136394712, wikipedia, wiki, book, books, library,
