Cadiot-Chodkiewicz coupling 5630017 225303111 2008-07-12T23:59:50Z 139.80.43.165 /* Hay coupling */ 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 (chemistry)|base]] <ref>Chodkiewicz, W. Ann. Chim. Paris '''1957''', 2, 819-869.</ref> <ref>Cadiot, P.; Chodkiewicz, W. In Chemistry of Acetylenes; Viehe, H. G., Ed.; Marcel Dekker: New York, '''1969'''; pp 597-647.</ref>. The reaction product is a di-acetylene or di-[[alkyne]]. [[Image:Cadiot-Chodkiewicz coupling overview.png|center|400px|Cadiot-Chodkiewicz coupling overview]] 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. ==Cadiot-Chodkiewicz coupling == In one study <ref>''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}}</ref> the Cadiot-Chodkiewicz coupling has been applied in the synthesis of acetylene [[macrocycle]]s 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|400px|center|Cadiot-Chodkiewicz coupling application]] The coupling reaction itself takes place in [[methanol]] with [[piperidine]], the [[hydrochloric acid]] salt of [[hydroxylamine]] and [[copper(I) bromide]]. ==Eglinton reaction== In the related '''Eglinton reaction''' <ref>G. Eglinton and A. R. Galbraith, J. Chem. Soc., 889 ('''1959''').</ref> two terminal alkynes are coupled directly a copper(II) salt such as [[cupric acetate]]. This procedure was used in the synthesis of [[cyclooctadecanonaene]]. Another example is the synthesis of diphenyldiacetylene from [[phenylacetylene]] <ref>{{OrgSynth | author = I. D. Campbell and G. Eglinton | title = Diphenyldiacetylene | collvol = 5 | collvolpages = 517 | year = 1973 | prep = cv5p0517}}</ref> ==Glaser coupling== The '''Glaser coupling''' (1870) is by far the oldest acetylenic coupling and is based on cuprous salts like [[copper(I) bromide]] and an additional oxidant like oxygen. The base in its original scope is [[ammonia]].<ref>{{cite journal | title = Untersuchungen über einige Derivate der Zimmtsäure | author = Carl Glaser | journal = Annalen der Chemie und Pharmacie | volume = 154 | issue = | pages = 137 | year = 1870 | url = | doi = 10.1002/jlac.18701540202 }}</ref><ref>{{cite journal | title = Beiträge zur Kenntniss des Acetenylbenzols | author = Carl Glaser | journal = Berichte der deutschen chemischen Gesellschaft | volume = 2 | issue = | pages = 422–424 | year = 1869 | url = | doi = 10.1002/cber.186900201183 }}</ref> ==Hay coupling== The Hay coupling (1962) is another version of the Glaser coupling with the [[TMEDA]] complex of [[copper(I) chloride]] <ref>{{cite journal | title = Oxidative Coupling of Acetylenes. II | author = Allan S. Hay | journal = [[J. Org. Chem.]] | year = 1962 | volume = 27 | issue 9 | pages = 3320–3321 | doi = 10.1021/jo01056a511}}</ref>.An example is the the coupling of [[trimethylsilylacetylene]] <ref>{{OrgSynth | title = 1,4-Bis(trimethylsilyl)buta-1,3-diyne | author = Graham E. Jones, David A. Kendrick, and Andrew B. Holmes | collvol = 8 | collvolpages = 63 | year = 1993 | prep = cv8p0063}}</ref> ==References== <references/> [[Category:Carbon-carbon bond forming reactions]] [[Category:Substitution reactions]] [[de:Cadiot-Chodkiewicz-Kupplung]] [[fr:Couplage de Cadiot-Chodkiewicz]] [[Category:Name reactions]]