Coupling reaction
In today's world, Coupling reaction is still a topic of interest to many people. With the advancement of technology and globalization, Coupling reaction has become a relevant topic in contemporary society. Whether Coupling reaction is a person, a historical event, or a current phenomenon, his impact on our lives cannot be underestimated. In this article, we will explore in depth the different facets of Coupling reaction, analyzing its importance, its implications and its influence in various areas. From its origin to its current state, Coupling reaction has left an indelible mark on society, and it is essential to understand its reach in order to better understand the world around us.
In organic chemistry, a coupling reaction is a type of reaction in which two reactant molecules are bonded together. Such reactions often require the aid of a metal catalyst. In one important reaction type, a main group organometallic compound of the type R-M (where R = organic group, M = main group centre metal atom) reacts with an organic halide of the type R'-X with formation of a new carbon–carbon bond in the product R-R'. The most common type of coupling reaction is the cross coupling reaction.[1][2][3]
Richard F. Heck, Ei-ichi Negishi, and Akira Suzuki were awarded the 2010 Nobel Prize in Chemistry for developing palladium-catalyzed cross coupling reactions.[4][5]
Broadly speaking, two types of coupling reactions are recognized:
- Homocouplings joining two identical partners. The product is symmetrical R−R
- Heterocouplings joining two different partners. These reactions are also called cross-coupling reactions.[6] The product is unsymmetrical, R−R'.
Homo-coupling types
Coupling reactions are illustrated by the Ullmann reaction:
| Reaction | Year | Organic compound | Coupler | Remark | |
|---|---|---|---|---|---|
| Wurtz reaction | 1855 | R-X | sp3 | Na as reductant | dry ether as medium |
| Pinacol coupling reaction | 1859 | R-HC=O or R2(C=O) | various metals | requires proton donor | |
| Glaser coupling | 1869 | RC≡CH | sp | Cu | O2 as H-acceptor |
| Ullmann reaction | 1901 | Ar-X | sp2 | Cu | high temperatures |
| Fittig reaction | Ar-X | sp2 | Na | dry ether as medium | |
| Scholl reaction | 1910 | ArH | sp2 | NaAlCl4(l) | O2 as H-acceptor; presumably trace Fe3+ catalyst; requires high heat |
Cross-coupling types
| Reaction | Year | Reactant A | Reactant B | Catalyst | Remark | ||
|---|---|---|---|---|---|---|---|
| Grignard reaction | 1900 | R-MgBr | sp, sp2, sp3 | R-HC=O or R(C=O)R2 | sp2 | not catalytic | |
| Gomberg–Bachmann reaction | 1924 | Ar-H | sp2 | Ar'-N2+X− | sp2 | not catalytic | |
| Cadiot–Chodkiewicz coupling | 1957 | RC≡CH | sp | RC≡CX | sp | Cu | requires base |
| Castro–Stephens coupling | 1963 | RC≡CH | sp | Ar-X | sp2 | Cu | |
| Corey–House synthesis | 1967 | R2CuLi or RMgX | sp3 | R-X | sp2, sp3 | Cu | Cu-catalyzed version by Kochi, 1971 |
| Cassar reaction | 1970 | Alkene | sp2 | R-X | sp3 | Pd | requires base |
| Kumada coupling | 1972 | Ar-MgBr | sp2, sp3 | Ar-X | sp2 | Pd or Ni or Fe | |
| Heck reaction | 1972 | alkene | sp2 | Ar-X | sp2 | Pd or Ni | requires base |
| Sonogashira coupling | 1975 | RC≡CH | sp | R-X | sp3 sp2 | Pd and Cu | requires base |
| Murahashi coupling[7] | 1975 | RLi | sp2, sp3 | Ar-X | sp2 | Pd or Ni | Pd-catalyzed version by Murahashi, 1979 |
| Negishi coupling | 1977 | R-Zn-X | sp3, sp2, sp | R-X | sp3 sp2 | Pd or Ni | |
| Stille reaction | 1978 | R-SnR3 | sp3, sp2, sp | R-X | sp3 sp2 | Pd | |
| Suzuki reaction | 1979 | R-B(OR)2 | sp2 | R-X | sp3 sp2 | Pd or Ni | requires base |
| Hiyama coupling | 1988 | R-SiR3 | sp2 | R-X | sp3 sp2 | Pd | requires base |
| Buchwald–Hartwig amination | 1994 | R2N-H | sp3 | R-X | sp2 | Pd | N-C coupling, second generation free amine |
| Fukuyama coupling | 1998 | R-Zn-I | sp3 | RCO(SEt) | sp2 | Pd or Ni[8] | |
| Liebeskind–Srogl coupling | 2000 | R-B(OR)2 | sp3, sp2 | RCO(SEt) Ar-SMe | sp2 | Pd | requires CuTC |
| (Li) Cross dehydrogenative coupling(CDC) | 2004 | R-H | sp, sp2, sp3 | R'-H | sp, sp2, sp3 | Cu, Fe, Pd etc | requires oxidant or dehydrogenation |
| Wurtz–Fittig reaction | 1864 | R-X | sp3 | Ar-X | sp2 | Na | dry ether |
Applications
Coupling reactions are routinely employed in the preparation of pharmaceuticals.[3] Conjugated polymers are prepared using this technology as well.[9]
References
- ^ Organic Synthesis using Transition Metals Rod Bates ISBN 978-1-84127-107-1
- ^ New Trends in Cross-Coupling: Theory and Applications Thomas Colacot (Editor) 2014 ISBN 978-1-84973-896-5
- ^ a b King, A. O.; Yasuda, N. (2004). "Palladium-Catalyzed Cross-Coupling Reactions in the Synthesis of Pharmaceuticals". Organometallics in Process Chemistry. Topics in Organometallic Chemistry. Vol. 6. Heidelberg: Springer. pp. 205–245. doi:10.1007/b94551. ISBN 978-3-540-01603-8.
- ^ "The Nobel Prize in Chemistry 2010 - Richard F. Heck, Ei-ichi Negishi, Akira Suzuki". NobelPrize.org. 2010-10-06. Retrieved 2010-10-06.
- ^ Johansson Seechurn, Carin C. C.; Kitching, Matthew O.; Colacot, Thomas J.; Snieckus, Victor (2012). "Palladium-Catalyzed Cross-Coupling: A Historical Contextual Perspective to the 2010 Nobel Prize". Angewandte Chemie International Edition. 51 (21): 5062–5085. doi:10.1002/anie.201107017. PMID 22573393.
- ^ Smith, Michael B.; March, Jerry (2007), Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (6th ed.), New York: Wiley-Interscience, p. 449, ISBN 978-0-471-72091-1
- ^ Hazra, Susanta; Johansson Seechurn, Carin C. C.; Handa, Sachin; Colacot, Thomas J. (2021-10-15). "The Resurrection of Murahashi Coupling after Four Decades". ACS Catalysis. 11 (21): 13188–13202. doi:10.1021/acscatal.1c03564. ISSN 2155-5435. S2CID 244613990.
- ^ Nielsen, Daniel K.; Huang, Chung-Yang (Dennis); Doyle, Abigail G. (2013-08-20). "Directed Nickel-Catalyzed Negishi Cross Coupling of Alkyl Aziridines". Journal of the American Chemical Society. 135 (36): 13605–13609. Bibcode:2013JAChS.13513605N. doi:10.1021/ja4076716. ISSN 0002-7863. PMID 23961769.
- ^ Hartwig, J. F. (2010). Organotransition Metal Chemistry, from Bonding to Catalysis. New York: University Science Books. ISBN 978-1-891389-53-5.
