| Staudinger reaction | |
|---|---|
| Named after | Hermann Staudinger |
| Reaction type | Organic redox reaction |
| Identifiers | |
| Organic Chemistry Portal | staudinger-reaction |
| RSC ontology ID | RXNO:0000066 |
TheStaudinger reaction is achemical reaction of anorganic azide with aphosphine orphosphite produces animinophosphorane.[1][2] The reaction was discovered by and named afterHermann Staudinger.[3] The reaction follows this stoichiometry:
TheStaudinger reduction is conducted in two steps. First phosphine imine-forming reaction is conducted involving treatment of the azide with the phosphine. The intermediate, e.g.triphenylphosphine phenylimide, is then subjected tohydrolysis to produce aphosphine oxide and anamine:
The overall conversion is a mild method ofreducing an azide to an amine.Triphenylphosphine ortributylphosphine are most commonly used, yielding tributylphosphine oxide ortriphenylphosphine oxide as a side product in addition to the desired amine. An example of a Staudinger reduction is theorganic synthesis of the pinwheel compound 1,3,5-tris(aminomethyl)-2,4,6-triethylbenzene.[4]
Thereaction mechanism centers around the formation of animinophosphorane throughnucleophilic addition of the aryl or alkylphosphine at the terminal nitrogen atom of the organic azide and expulsion ofdiatomicnitrogen. The iminophosphorane is then hydrolyzed in the second step to the amine and a phosphine oxide byproduct.
Of interest inchemical biology is theStaudinger ligation, which has been called one of the most important bioconjugation methods.[5] Two versions of the Staudinger ligation have been developed. Both begin with the classic iminophosphorane reaction.
In the classical Staudinger ligation, theorganophosphorus compound becomes incorporated into the nascent amide.[6] Typically, appended to the organophosphorus component are reporter groups such as fluorophores. In the traceless Staudinger ligation, the organophosphorus group dissociates, giving a phosphorus-free peptide or bioconjugate.[7][8]
