Global InformationSandmeyer reaction information
| Sandmeyer reaction | |
|---|---|
| Named after | Traugott Sandmeyer |
| Reaction type | Substitution reaction |
| Identifiers | |
| Organic Chemistry Portal | sandmeyer-reaction |
| RSC ontology ID | RXNO:0000021 |
The Sandmeyer reaction is a chemical reaction used to synthesize aryl halides from aryl diazonium salts using copper salts as reagents or catalysts.[1][2][3][4] It is an example of a radical-nucleophilic aromatic substitution. The Sandmeyer reaction provides a method through which one can perform unique transformations on benzene, such as halogenation, cyanation, trifluoromethylation, and hydroxylation.
The reaction was discovered in 1884 by Swiss chemist Traugott Sandmeyer, when he attempted to synthesize phenylacetylene from benzenediazonium chloride and copper(I) acetylide. Instead, the main product he isolated was chlorobenzene.[5] In modern times, the Sandmeyer reaction refers to any method for substitution of an aromatic amino group via preparation of its diazonium salt followed by its displacement with a nucleophile in the presence of catalytic copper(I) salts.
The most commonly employed Sandmeyer reactions are the chlorination, bromination, cyanation, and hydroxylation reactions using CuCl, CuBr, CuCN, and Cu2O, respectively. More recently, trifluoromethylation of diazonium salts has been developed and is referred to as a 'Sandmeyer-type' reaction. Diazonium salts also react with boronates, iodide, thiols, water, hypophosphorous acid and others,[6] and fluorination can be carried out using tetrafluoroborate anions (Balz–Schiemann reaction). However, since these processes do not require a metal catalyst, they are not usually referred to as Sandmeyer reactions. In numerous variants that have been developed, other transition metal salts, including copper(II), iron(III) and cobalt(III) have also been employed.[7] Due to its wide synthetic applicability, the Sandmeyer reaction, along with other transformations of diazonium compounds, is complementary to electrophilic aromatic substitution.
- ^ Smith, Michael B.; March, Jerry (2007), Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (6th ed.), New York: Wiley-Interscience, pp. 984–985, ISBN 978-0-471-72091-1
- ^ Traugott Sandmeyer (1884). "Ueber die Ersetzung der Amidgruppe durch Chlor in den aromatischen Substanzen". Berichte der deutschen chemischen Gesellschaft. 17 (3): 1633–1635. doi:10.1002/cber.18840170219.
- ^ Traugott Sandmeyer (1884). "Ueber die Ersetzung der Amid-gruppe durch Chlor, Brom und Cyan in den aromatischen Substanzen". Berichte der Deutschen Chemischen Gesellschaft. 17 (4): 2650–2653. doi:10.1002/cber.188401702202.
- ^ Ludwig Gattermann (1890). "Untersuchungen über Diazoverbindungen". Berichte der Deutschen Chemischen Gesellschaft. 23 (1): 1218–1228. doi:10.1002/cber.189002301199.
- ^ Hodgson, Herbert H. (1947-04-01). "The Sandmeyer Reaction". Chemical Reviews. 40 (2): 251–277. doi:10.1021/cr60126a003. ISSN 0009-2665. PMID 20291034.
- ^ Wang, Zerong (2010). "Sandmeyer Reaction". Comprehensive Organic Name Reactions and Reagents. John Wiley & Sons, Inc. pp. 2471–2475. ISBN 9780470638859.
- ^ M. P. Doyle, B. Siegfried and J. F. Dellaria (1977). "Alkyl nitrite-metal halide deamination reactions. 2. Substitutive deamination of arylamines by alkyl nitrites and copper(II) halides. A direct and remarkably efficient conversion of arylamines to aryl halides". J. Org. Chem. 42 (14): 2426–2431. doi:10.1021/jo00434a017.