The Staudinger reaction
or Staudinger reduction
is a chemical reaction
in which the combination of an azide
with a phosphine
produces an iminophosphorane
intermediate . Combined with the hydrolysis
of the aza-ylide to produce a phosphine oxide
and an amine
, this reaction is a mild method of 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 :
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:
This intermediate is then hydrolyzed in the second step to the amine and triphenylphosphine oxide.
Developed by Saxon and Bertozzi in 2000, the Staudinger ligation
is a modification of the classical Staudinger reaction in which an electrophilic trap
(usually a methyl ester
) is appropriately placed on the triaryl phosphine . 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.
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 :
- Staudinger Reaction at organic-chemistry.org accessed 060906.