Staudinger reaction
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The '''Staudinger reaction''' or '''Staudinger reduction''' is a [[chemical reaction]] in which the combination of an [[azide]] with a [[phosphine]] or [[phosphite]] produces an [[iminophosphorane]] intermediate <ref>[[Hermann Staudinger|Staudinger, H.]]; Meyer, J. ''Helv. Chim. Acta'' '''1919''', ''2'', 635.</ref> <ref>Gololobov, Y. G. ''et al.'' ''[[Tetrahedron (journal)|Tetrahedron]]'' '''1981''', ''37'', 437.</ref>. Combined with the [[hydrolysis]] of the aza-ylide to produce a [[phosphine oxide]] and an [[amine]], this reaction is a mild method of [[organic reduction|reducing]] an azide to an amine. [[Triphenylphosphine]] is commonly used as the [[reducing agent]], yielding [[triphenylphosphine oxide]] as the side product in addition to the amine.
The reaction was invented by and named after [[Hermann Staudinger]].
An example of a Staudinger reduction is the [[organic synthesis]] of this pinwheel compound <ref>''Preparation of 1,3,5-Tris(aminomethyl)-2,4,6-triethylbenzene from Two Versatile 1,3,5-Tri(halosubstituted) 2,4,6-Triethylbenzene Derivatives'' Karl J. Wallace, Robert Hanes, Eric Anslyn, Jeroni Morey, Kathleen V. Kilway, Jay Siegeld Synthesis '''2005''': 2080-2083. ([http://www.thieme-connect.com/ejournals/abstract/synthesis/doi/10.1055/s-2005-869963 Abstract])</ref>:
[[Image:Staudingerreduction.gif|center|example Staudinger reduction]]
==Reaction mechanism==
The [[reaction mechanism]] centers around the formation of an [[iminophosphorane]] through [[nucleophilic addition]] of the [[phosphine]] at the terminal nitrogen atom of the azide and expulsion of nitrogen:
[[Image:Staudinger.png|center|The Staudinger reaction]]
This intermediate is then hydrolyzed in the second step to the [[amine]] and [[triphenylphosphine oxide]].
==Staudinger ligation==
Developed by Saxon and Bertozzi in 2000, the '''Staudinger ligation''' is a modification of the classical Staudinger reaction in which an electrophilic [[chemical trap|trap]] (usually a [[methyl ester]]) is appropriately placed on the triaryl phosphine <ref>Saxon, E.; Bertozzi, C.R. ''[[Science (journal)|Science]]'' '''2000''', ''287'', 2007.</ref>. In the Staudinger ligation, the aza-ylide intermediate rearranges, in aqueous media, to produce an [[amide]] linkage and the phosphine oxide, and is so named the Staudinger ligation because it ligates the two molecules together, whereas in the classical Staudinger reaction, the two products are not covalently linked after hydrolysis.
The general schematic for the Staudinger ligation is shown below.
[[Image:Staudinger_ligation2.gif|center|example Staudinger ligation]]
===Applications===
The Staudinger ligation has seen many applications in the field of [[chemical biology]].
In one application this reaction is used to create a bond between a [[nucleoside]] and a [[fluorescent]] marker <ref>''Synthesis of coumarin or ferrocene labeled nucleosides via Staudinger ligation'' Kosiova I, Janicova A, Kois P [[Beilstein Journal of Organic Chemistry]], '''2006''' 2:23 ( 30 November 2006 ) {{doi|10.1186/1860-5397-2-23}}</ref> <ref>the nucleoside is based on [[deoxyuridine]], the marker is a [[coumarin]] with a carboxyl group activated by [[HOBT]]</ref> :
[[Image:StaudingLigationApplication.png|center|500px|Stauding Ligation Application Kosiova 2006]]
==References==
<div class="references-small"><references/></div>
==External links==
#[http://www.organic-chemistry.org/namedreactions/staudinger-reaction.shtm Staudinger Reaction at organic-chemistry.org] accessed 060906.
[[Category:Organic redox reactions]]
[[Category:Name reactions]]
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