Cadiot-Chodkiewicz coupling
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The Cadiot-Chodkiewicz coupling in organic chemistry is a coupling reaction between a terminal alkyne and a haloalkyne catalyzed by a copper(I) salt such as copper(I) bromide and an amine base [1] [2]. The reaction product is a di-acetylene or di-alkyne.
The reaction mechanism involves deprotonation by base of the acetylenic proton followed by formation of a copper(I) acetylide. A cycle of oxidative addition and reductive elimination on the copper center then creates a new carbon carbon bond.
Related couplings are the Glaser coupling and the Eglinton coupling.
[edit] Scope
In one study [3] the Cadiot-Chodkiewicz coupling has been applied in the synthesis of acetylene macrocycles starting from cis-1,4-diethynyl-1,4-dimethoxycyclohexa-2,5-diene. This compound is also the starting material for the dibromide through NBS and silver nitrate:
The coupling reaction itself takes place in methanol with piperidine, the hydrochloric acid salt of hydroxylamine and copper(I) bromide.
[edit] References
- ^ Chodkiewicz, W. Ann. Chim. Paris 1957, 2, 819-869.
- ^ Cadiot, P.; Chodkiewicz, W. In Chemistry of Acetylenes; Viehe, H. G., Ed.; Marcel Dekker: New York, 1969; pp 597-647.
- ^ Synthesis of 1,4-Cyclohexadiene-Based Acetylenic Macrocycles with Cadiot-Chodkiewicz Coupling. Structure of a Tub-Shaped Tetrameric Container Arkasish Bandyopadhyay, Babu Varghese, and Sethuraman Sankararaman J. Org. Chem.; 2006; 71(12) pp 4544 - 4548; (Article) DOI:10.1021/jo0605290
