Tetraethylammonium trichloride (also known as Mioskowski reagent)[2] is a chemical compound with the formula [NEt4][Cl3] consisting of a tetraethylammonium cation and a trichloride as anion. The trichloride is also known as trichlorine monoanion representing one of the simplest polychlorine anions.[3] Tetraethylammonium trichloride is used as reagent for chlorinations and oxidation reactions.
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| Names | |
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| Other names
Mioskowski reagent
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| Identifiers | |
3D model (JSmol)
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PubChem CID
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| Properties | |
| C8H20Cl3N | |
| Molar mass | 236.61 g·mol−1 |
| Appearance | yellow solid |
| Solubility | Dichloromethane, ethanol, acetonitrile, pyridine[1] |
| log P | 3.95 |
| Related compounds | |
Related compounds
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Triethylmethylammonium trichloride |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Properties
editAt room temperature, tetraethylammonium trichloride is a yellow solid which is soluble in polar organic solvents (e.g., methylene chloride or acetonitrile). As it is a strong oxidant and chlorinating agent it is reacting with most organic solvents.[1] The trichloride can be considered as an symmetric anion as found in [NnPr4][Cl3], which is formed by a 3c-4e bond.[4]
Preparation
editCommonly, tetraethylammonium trichloride is prepared by the reaction of tetraethylammonium chloride and elemental chlorine in methylene chloride at room temperature. After evaporation of the solvent, tetraethylammonium trichloride is obtained as a yellow solid.
[NEt4]Cl + Cl2 → [NEt4][Cl3]
Recently, an alternative preparation of tetraethylammonium trichloride has been described using tetraethylammonium chloride and potassium peroxymonosulfate as oxidant.[2]
Applications
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In general, tetraethylammonium trichloride has a similar reactivity compared to elemental chlorine and other trichlorides, e.g., triethylmethylammonium trichloride. As tetraethylammonium trichloride is a solid and can be dissolved in methylene chloride or acetonitrile, it is used as an easier to handle alternative to elemental chlorine, in particular for the synthesis of intermediates in natural product synthesis.[5][6][7] Tetraethylammonium trichloride reacts with alkenes to the corresponding vicinal 1,2-dichlorinated alkanes and similarly with alkynes to the corresponding trans-dichlorinated alkenes. Electron rich arenes are chlorinated in para-position. While aldehydes are dichlorinated in alpha-position, ketones react to the monochlorinated alpha-chloroketones. In presence of 1,4-diazabicyclo[2.2.2]octane tetraethylammonium trichloride is a useful oxidant for the oxidation of primary alcohols to the corresponding aldehydes and of secondary alcohols to the corresponding ketones. For compounds bearing both a primary and a secondary alcohol, selective oxidation of the secondary alcohol is observed. Acetals undergo C-H chlorination of the tertiary C-H bond providing the corresponding chlorinated acetals.[1]
References
edit- ^ a b c Schlama T, Gabriel K, Gouverneur V, Mioskowski C (1997-11-14). "Tetraethylammonium Trichloride: A Versatile Reagent for Chlorinations and Oxidations". Angewandte Chemie International Edition in English (in German). 36 (21). pp. 2342–2344. doi:10.1002/anie.199723421. ISSN 0570-0833.
- ^ a b Ren J, Tong R (July 2013). "Convenient in situ generation of various dichlorinating agents from oxone and chloride: diastereoselective dichlorination of allylic and homoallylic alcohol derivatives". Organic & Biomolecular Chemistry. 11 (26): 4312–5. doi:10.1039/c3ob40670a. PMID 23715511.
- ^ Sonnenberg K, Mann L, Redeker FA, Schmidt B, Riedel S (March 2020). "Polyhalogen and Polyinterhalogen Anions from Fluorine to Iodine". Angewandte Chemie. 59 (14): 5464–5493. doi:10.1002/anie.201903197. PMID 31090163. S2CID 155093006.
- ^ Keil H, Sonnenberg K, Müller C, Herbst-Irmer R, Beckers H, Riedel S, Stalke D (February 2021). "Insights into the Topology and the Formation of a Genuine ppσ Bond: Experimental and Computed Electron Densities in Monoanionic Trichlorine [Cl3 ]". Angewandte Chemie. 60 (5): 2569–2573. doi:10.1002/anie.202013727. PMC 7898528. PMID 33151006.
- ^ Nilewski C, Deprez NR, Fessard TC, Li DB, Geisser RW, Carreira EM (August 2011). "Synthesis of undecachlorosulfolipid A: re-evaluation of the nominal structure". Angewandte Chemie. 50 (34): 7940–7943. doi:10.1002/anie.201102521. PMID 21744447.
- ^ Huwyler N, Carreira EM (December 2012). "Total synthesis and stereochemical revision of the chlorinated sesquiterpene (±)-gomerone c". Angewandte Chemie International Edition in English. 51 (52): 13066–9. doi:10.1002/anie.201207203. PMID 23161813.
- ^ Ju W, Wang X, Tian H, Gui J (August 2021). "Asymmetric Total Synthesis of Clionastatins A and B". Journal of the American Chemical Society. 143 (33): 13016–13021. doi:10.1021/jacs.1c07511. PMID 34398601. S2CID 237149721.