Tetrapropylammonium perruthenate
Tetrapropylammonium perruthenate (TPAP or TPAPR) is the chemical compound described by the formula N(C3H7)4RuO4. Sometimes known as the Ley–Griffith reagent, this ruthenium compound is used as a reagent in organic synthesis. This salt consists of the tetrapropylammonium cation and the perruthenate anion, RuO−4.
| Names | |
|---|---|
| IUPAC name
Tetrapropylammonium perruthenate | |
| Identifiers | |
3D model (JSmol) |
|
| Abbreviations | TPAP TPAPR |
| ChemSpider | |
| ECHA InfoCard | 100.156.687 |
PubChem CID |
|
| UNII | |
CompTox Dashboard (EPA) |
|
| |
| |
| Properties | |
| C12H28NRuO4 | |
| Molar mass | 351.43 g/mol |
| Appearance | Green solid |
| Melting point | 160 °C (320 °F; 433 K) (decomposition) |
| Hazards | |
| GHS labelling: | |
| Warning | |
| H272, H315, H319, H335 | |
| P210, P220, P221, P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P370+P378, P403+P233, P405, P501 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references | |
Uses
Ruthenium tetroxide is a highly aggressive oxidant, but TPAP, which is its one-electron reduced derivative, is a mild oxidizing agent for the conversion of primary alcohols to aldehydes (the Ley oxidation).[2] Secondary alcohols are similarly oxidized to ketones.[3] It can also be used to oxidize primary alcohols all the way to the carboxylic acid with a higher catalyst loading, larger amount of the cooxidant, and addition of two equivalents of water. In this situation, the aldehyde reacts with water to form the geminal diol hydrate, which is then oxidized again.[4]
The oxidation generates water that can be removed by adding molecular sieves. TPAP is expensive, but it can be used in catalytic amounts. The catalytic cycle is maintained by adding a stoichiometric amount of a co-oxidant such as N-methylmorpholine N-oxide[5] or molecular oxygen.[6]
TPAP is also used to cleave vicinal diols to form aldehydes.[3]
References
- Hadfield, John A.; McGown, Alan T.; Butler, John (2000). "A high-yielding synthesis of the naturally occurring antitumour agent irisquinone" (PDF). Molecules. 5 (12): 82–88. doi:10.3390/50100082.
- Ley, Steven V.; Norman, Joanne; Griffith, William P.; Marsden, Stephen P. (1994). "Tetrapropylammonium perruthenate, Pr4N+RuO4−, TPAP: A catalytic oxidant for organic synthesis". Synthesis. 1994 (7): 639–666. doi:10.1055/s-1994-25538. S2CID 95136192. (review article)
- Ley, Steven V.; Norman, Joanne; Wilson, Anthony J. (2011), "Tetra-n-propylammonium Perruthenate", Encyclopedia of Reagents for Organic Synthesis, Chichester, UK: John Wiley & Sons, Ltd, pp. rt074.pub2, doi:10.1002/047084289x.rt074.pub2, ISBN 978-0-471-93623-7, retrieved 2020-09-04
- Xu, Z.; Johannes, C. W.; Houri, A. F.; La, D. S.; Cogan, D. A.; Hofilena, G. E.; Hoveyda, A. H. (1997). "Applications of Zr-catalyzed carbomagnesation and Mo-catalyzed macrocyclic ring closing metathesis in asymmetric synthesis. Enantioselective total synthesis of Sch 38516 (Fluvirucin B1)". J. Am. Chem. Soc. 119 (43): 10302–10316. doi:10.1021/ja972191k.
- Griffith, William P.; Ley, Steven V.; Whitcombe, Gwynne P.; White, Andrew D. (1987). "Preparation and use of tetra-n-butylammonium per-ruthenate (TBAP reagent) and tetra-n-propylammonium per-ruthenate (TPAP reagent) as new catalytic oxidants for alcohols". J. Chem. Soc., Chem. Commun. (21): 1625–1627. doi:10.1039/C39870001625.
- Lenz, Roman; Ley, Steven V. (1997). "Tetra-n-propylammonium perruthenate (TPAP)-catalysed oxidations of alcohols using molecular oxygen as a co-oxidant". J. Chem. Soc., Perkin Trans. 1 (22): 3291–3292. doi:10.1039/A707339I.