Barton–Kellogg reaction
Source: Wikipedia, the free encyclopedia.
| Barton–Kellogg reaction | |
|---|---|
| Named after | Sir Derek Barton Richard M. Kellogg |
| Reaction type | Coupling reaction |
| Identifiers | |
| RSC ontology ID | RXNO:0000495 |
The Barton–Kellogg reaction is a coupling reaction between a diazo compound and a thioketone, giving an alkene by way of an episulfide intermediate.[1][2][3] The Barton–Kellogg reaction is also known as Barton–Kellogg olefination[4] and Barton olefin synthesis.[5]
This reaction was pioneered by Hermann Staudinger,[6] and also goes by the name Staudinger type diazo-thioketone coupling.
Reaction mechanism
In the
thiocarbonyl ylide, which then cyclizes to form a stable episulfide. Triphenylphosphine reacts as a nucleophile, opening the three-membered ring to form a sulfaphosphatane. In a manner similar to the Wittig reaction, this structure then expels triphenylphosphine sulfide
to produce an alkene.
Scope
The diazo compound can be obtained from a
(bis(trifluoroacetoxy)iodo)benzene.[7] The thioketone required for this reaction can be obtained from a ketone and phosphorus pentasulfide. Desulfurization of the episulfide can be accomplished by many phosphines and also by copper
powder.
The main advantage of this reaction over the McMurry reaction is the notion that the reaction can take place with two different ketones. In this regard the diazo-thioketone coupling is a cross-coupling rather than a homocoupling.
References
- .
- .
- .
- ISBN 9780470638859.
- ^ "Barton olefin synthesis". Merck Index (15th ed.).
- .
- PMID 15602594.