“Wurtz–Fittig reaction”的意思、由来-开放百科全书

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]

Mechanism

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.

The second approach involves the formation of an intermediate organo-alkali compound followed by nucleophilic attack of the alkyl halide.

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 cholorobenzene, 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.

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 bubbling carbon dioxide through a mixture of sodium and isobutyl bromide results in the formation of 3-methylbutanoic acid.

The formation of 3-methylbutanoic acid follows from a nucelophilic 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 via 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 via the Wurtz–Fittig reaction include silylated calixarenes,^[18] t-Butylsilicon compounds,^[19] and vinylsilanes.^[20] For example, t-butyltriethoxysilane can be prepared via the Wurtz–Fitting reaction by combining tetraoxysilane, t-butyl choride and molten sodium. The reaction proceeds with a 40% yield.^[19]

See also

References

1. ^¹{{cite book |chapter= Wurtz–Fittig Reaction |first1= Zerong |last1= Wang |isbn= 9780470638859 |doi= 10.1002/9780470638859.conrr686 |year= 2010 |title= Comprehensive Organic Name Reactions and Reagents |volume= 686 |pages= 3100–3104}}
2. ^{{cite journal|first = Adolphe|last = Wurtz|authorlink = Charles Adolphe Wurtz|year = 1855|title = Sur une Nouvelle Classe de Radicaux Organiques |language = French|trans-title = On a New Class of Organic Radicals|journal = Annales de Chimie et de Physique|volume = 44|page = 275–312|url = http://gallica.bnf.fr/ark:/12148/bpt6k34785p/f274.table}}
3. ^{{cite journal |first = A.|last = Wurtz|authorlink = Charles Adolphe Wurtz|year = 1855|title = Ueber eine neue Klasse organischer Radicale|language = German|trans-title = About a new class of organic radicals|journal = Justus Liebigs Annalen der Chemie|volume = 96|issue = 3|pages = 364–375|doi = 10.1002/jlac.18550960310}}
4. ^{{cite book |chapter= Wurtz Synthesis (Wurtz Reaction, Wurtz Reductive Coupling) |year= 2010 |first1= Zerong |last1= Wang |isbn= 9780470638859 |doi= 10.1002/9780470638859.conrr685 |title= Comprehensive Organic Name Reactions and Reagents |volume= 685 |pages= 3094–3099}}
5. ^{{cite book|title = Alkanes|series = Science of Synthesis: Houben-Weyl Methods of Molecular Transformations|volume = 48|publisher = Georg Thieme Verlag|year = 2014|chapter = 48.1.2.4 Method 4: Reductive Coupling of Alkyl Halides|editor-first = H.|editor-last = Hiemstra|first1 = Eric Asssen B.|last1 = Kantchev|first2 = Michael G.|last2 = Organ|isbn = 9783131784810|chapter-url = https://books.google.com/books?id=duuIAwAAQBAJ&pg=RA2-PA9}}
6. ^{{cite journal | title = Ueber die Synthese der Kohlenwasserstoffe der Benzolreihe | language = German | trans-title = On the synthesis of the hydrocarbons of the benzene series | first1 = Bernhard | last1 = Tollens | authorlink1 = Bernhard Tollens | first2 = Rudolph | last2 = Fittig | authorlink2 = Rudolph Fittig | journal = Justus Liebigs Annalen der Chemie | volume = 131 | issue = 3 | pages = 303–323 | year = 1864 | doi = 10.1002/jlac.18641310307}}
7. ^{{cite journal | title = Ueber das Aethyl- und Diäthylbenzol | language = German | trans-title = About ethyl- and diethylbenzene | first1 = Rudolph | last1 = Fittig | authorlink1 = Rudolph Fittig | first2 = Joseph | last2 = König | journal = Justus Liebigs Annalen der Chemie | volume = 144 | issue = 3 | pages = 277–294 | year = 1867 | doi = 10.1002/jlac.18671440308}}
8. ^{{cite book |last=Desai |first=K. R. |title=Organic Name Reactions |year=2008 |publisher=Oxford Book Company |location=Jaipur, India |isbn=9788189473327 |page=259 }}
9. ^{{cite book |last1=Laue |first1=Thomas |last2=Plagens |first2=Andreas |title=Named Organic Reactions |edition=2nd |year=2005 |publisher=John Wiley & Sons |location=Wolfsburg, Germany |isbn=9780470010402 |page=305}}
10. ^¹{{Cite journal |last1=Wooster |first1=Charles Bushnell |year=1932 |title=Organo-alkali Compounds |journal=Chemical Reviews |volume=11 |issue=1 |pages=1–91 |doi=10.1021/cr60038a001 |issn=0009-2665}}
11. ^¹{{Cite journal |last1=Gilman |first1=Henry |last2=Wright |first2=George F. |year=1933 |title=The Mechanism of the Wurtz—Fittig Reaction. The Direct Preparation of an Organosodium (Potassium) Compound from an RX Compound |journal=Journal of the American Chemical Society |volume=55 |issue=7 |pages=2893–2896 |doi=10.1021/ja01334a044 |issn=0002-7863}}
12. ^¹²{{Cite journal |last1=Bachmann |first1=W. E. |last2=Clarke |first2=H. T. |year=1927 |title=The Mechanism of the Wurtz–Fittig Reaction |journal=Journal of the American Chemical Society |volume=49 |issue=8 |pages=2089–2098 |doi=10.1021/ja01407a038 |issn=0002-7863}}
13. ^Schoruigin: Ber. 41, 2711-7 (1908); ibid. 43, 1938-42 (1910).
14. ^¹{{Cite book |title=March's advanced organic chemistry: Reactions, mechanisms, and structure.|last1=Smith |first1=Michael |year=2007 |publisher=Wiley-Interscience |last2=March |first2=Jerry |authorlink2=Jerry March |isbn=978-0471720911 |edition=6th |location=Hoboken, N.J. |oclc=69020965}}
15. ^{{Cite journal |year=1981 |title=Organic sonochemistry. Ultrasound-promoted coupling of organic halides in the presence of lithium wire |first1=Byung Hee |last1=Han |first2=Philip |last2=Boudjouk |journal=Tetrahedron Letters |volume=22 |issue=29 |pages=2757–2758 |doi=10.1016/S0040-4039(01)90544-1 |issn=0040-4039}}
16. ^{{Cite journal |year=1965 |title=Sonocleavage of halogens from aliphatic chains and aromatic rings |first1=S. |last1=Prakash |first2=J. D. |last2=Pandey |journal=Tetrahedron |volume=21 |issue=4 |pages=903–908 |doi=10.1016/0040-4020(65)80026-6 |issn=0040-4020}}
17. ^{{Cite journal|title=The use of the Wurtz–Fittig reaction in the preparation of organo-substituted silanes|last1=Bassett|first1=E. A.|last2=Emblem|first2=H. G.|last3=Frankel|first3=M.|last4=Ridge|first4=D.|year=1948|journal=Journal of the Society of Chemical Industry|volume=67|issue=5|pages=177–179|doi=10.1002/jctb.5000670503|issn=0368-4075}}
18. ^{{Cite journal|title=The Wurtz–Fittig Reaction in the Preparation of C-Silylated Calixarenes|last1=Hudrlik|first1=Paul F.|last2=Arasho|first2=Wondwossen D.|last3=Hudrlik|first3=Anne M.|year=2007|journal=The Journal of Organic Chemistry|volume=72|issue=21|pages=8107–8110|doi=10.1021/jo070660n|pmid=17850095|issn=0022-3263}}
19. ^¹{{Cite journal|last1=Chappelow|first1=C. C.|last2=Elliott|first2=R. L.|last3=Goodwin|first3=J. T.|year=1962|title=Synthesis of t-Butylsilicon Compounds by the Wurtz–Fitting Reaction1|journal=The Journal of Organic Chemistry|volume=27|issue=4|pages=1409–1414|doi=10.1021/jo01051a069|issn=0022-3263}}
20. ^{{Cite journal|last1=Adam|first1=Waldemar|last2=Richter|first2=Markus J.|year=1994|title=One-Pot Synthesis of α-Trimethylsilyl Enones from Vinylsilanes|journal=Synthesis|volume=1994|issue=2|pages=176–180|doi=10.1055/s-1994-25433|issn=0039-7881}}