Cadiot–Chodkiewicz coupling
{{Short description|Reaction in organic chemistry}}
{{Use dmy dates|date=December 2022}}
{{Reactionbox
|Name = Cadiot–Chodkiewicz coupling
|Type = Coupling reaction
|NamedAfter = Paul Cadiot
Wladyslaw Chodkiewicz
|Section3 = {{Reactionbox Identifiers
|OrganicChemistryNamed = cadiot-chodkiewicz-coupling
|RSC_ontology_id = 0000100
}}
}}
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.Chodkiewicz, W. Ann. Chim. Paris 1957, 2, 819–69.Cadiot,
P.; Chodkiewicz, W. In Chemistry of Acetylenes; Viehe, H. G., Ed.; Marcel Dekker: New York, 1969; pp. 597–647. The reaction product is a 1,3-diyne or di-alkyne.
File:Cadiot-Chodkiewicz-Kupplung.svg
The reaction mechanism involves deprotonation by base of the terminal alkyne proton followed by formation of a copper(I) acetylide. A cycle of oxidative addition and reductive elimination on the copper centre then creates a new carbon-carbon bond.
Scope
Unlike the related Glaser coupling the Cadiot–Chodkiewicz coupling proceeds selectively and will only couple the alkyne to the haloalkyne, giving a single product. By comparison the Glaser coupling would simply produce a distribution of all possible couplings.
In one study{{cite journal|last1 = Bandyopadhyay|first1 = Arkasish|last2 = Varghese|first2 = Babu|last3 = Sankararaman|first3 = Sethuraman|title = Synthesis of 1,4-Cyclohexadiene-Based Acetylenic Macrocycles with Cadiot–Chodkiewicz Coupling. Structure of a Tub-Shaped Tetrameric Container|year = 2006|journal = Journal of Organic Chemistry|volume = 71|issue = 12|pages = 4544–4548|pmid = 16749787|doi = 10.1021/jo0605290}} 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 N-bromosuccinimide (NBS) and silver nitrate:
Image:Cadiot-Chodkiewicz coupling application.png
The coupling reaction itself takes place in methanol with piperidine, the hydrochloric acid salt of hydroxylamine and copper(I) bromide.
See also
- Glaser coupling – Another alkyne coupling reaction catalysed by a copper(I) salt.
- Sonogashira coupling – Pd/Cu catalysed coupling of an alkyne with an aryl or vinyl halide
- Castro–Stephens coupling – A cross-coupling reaction between a copper(I) acetylide and an aryl halide
References
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{{Alkynes}}
{{Organic reactions}}
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Category:Substitution reactions