Coupling reaction
Coupling reaction is formally using a catalytically active metal complex two hydrocarbons are interconnected by a new carbon -carbon bond in the organic chemistry of the preamble of a series of reactions where the organometallic.
A distinction between cross-coupling reactions and homo-coupling reactions. In the first type, two different hydrocarbons react to a new product, the second type is the coupling of two identical.
- Homo-coupling reaction of aryl iodides (eg Ullmann reaction)
- Cross-coupling reaction (eg, Stille coupling )
A commonly used metal in this type of reaction is palladium, very often as tetrakis (triphenylphosphine) palladium (0). This is made in situ by the then needed in the special coupling reaction complex.
Most of the reactions are very sensitive to traces of water or oxygen is necessary a reaction under inert gas atmosphere. This sensitivity is due primarily to the fact that in the reactions often intermediate unsaturated metal complexes ( less than 18 valence electrons ) are produced, which would be able to absorb oxygen and thus introduce more side reactions.
The most important coupling reactions are:
- Heck
- Suzuki coupling
- Hiyama coupling
- Sonogashira coupling
- Wurtzreaktion
- Ullmann reaction
- Stille coupling
- Kumada coupling ( Grignard reagents based on )
- Negishi coupling
- Catalysis
- Coupling reaction