Cadiot–Chodkiewicz coupling

Cadiot-Chodkiewicz-Kupplung

Cadiot-Chodkiewicz coupling application

Cadiot–Chodkiewicz coupling is an organic chemistry reaction that forms a carbon-carbon bond between two different alkynes, one of which must possess a leaving group, typically a halide. This reaction is a valuable tool in the synthesis of conjugated enynes and polyynes, compounds that are of significant interest due to their electronic properties and potential applications in materials science and pharmaceuticals. The Cadiot–Chodkiewicz coupling is named after the French chemist Pierre Cadiot and the Polish chemist Wladyslaw Chodkiewicz, who developed the reaction.

Mechanism

The Cadiot–Chodkiewicz coupling mechanism involves a copper(I) catalyst, often CuCl or a Cu(I) acetylide complex. The reaction proceeds through the formation of a copper acetylide by the reaction of the copper(I) salt with the terminal alkyne that has a hydrogen atom. This copper acetylide then reacts with the alkyne that has a leaving group (usually a halide) to form a new carbon-carbon bond, resulting in the formation of a conjugated diyne. The process is an example of a homocoupling reaction, although it couples two different alkynes.

Applications

The Cadiot–Chodkiewicz coupling has been applied in the synthesis of complex natural products and in the construction of molecules for materials science, including organic conductors and liquid crystals. Its ability to selectively form conjugated enynes and polyynes makes it a powerful tool in the synthesis of compounds with specific electronic properties.

Advantages and Limitations

One of the main advantages of the Cadiot–Chodkiewicz coupling is its ability to form conjugated systems without the need for pre-functionalization of the alkyne substrates, which can be a limitation in other coupling reactions such as the Sonogashira coupling. However, the reaction's efficiency can be affected by the nature of the substituents on the alkynes, and the need for a copper catalyst can limit its applicability in certain contexts, especially in the presence of sensitive functional groups.

See Also

• Sonogashira coupling
• Glaser coupling
• Hay coupling
• Alkyne metathesis