Tetrapropylammonium perruthenate

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Tetrapropylammonium perruthenate
TPAP.png
Identifiers
Abbreviations TPAP
TPAPR
CAS number 114615-82-6 YesY
Jmol-3D images Image 1
Properties
Molecular formula C12H28NRuO4
Molar mass 351.43 g/mol
Appearance Green solid
Melting point 160 °C (320 °F; 433 K) (decomposition)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

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, RuO4 anion. Ruthenium tetroxide is a highly aggressive oxidant, but its one-electron reduced derivative is a mild oxidizing agent for the conversion of alcohols to aldehydes.[1] This oxidizing agent can also be used to oxidize primary alcohols all the way to the carboxylic acid. Use of a higher catalyst loading, larger amount of the co-oxidant, 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.[2]

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 or molecular oxygen.[3]

Oxidation of alcohol to aldehyde with TPAP (0.06 eq.) and N-methylmorpholine N-oxide (1.7 eq.) with molecular sieves in dichloromethane.[4]


References[edit]

  1. ^ Ley, Steven V.; Norman, Joanne; Griffith, William P.; Marsden (1994). "Tetrapropylammonium Perruthenate, Pr4N+RuO4, TPAP: A Catalytic Oxidant for Organic Synthesis". Synthesis: 639–666. doi:10.1055/s-1994-25538.  |first4= missing |last4= in Authors list (help) (review article)
  2. ^ 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: 10302–10316. doi:10.1021/ja972191k. 
  3. ^ 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: 3291–. doi:10.1039/C39870001625. [dead link]
  4. ^ Hadfield, John A.; McGown, Alan T.; Butler, John (2000). "A High-Yielding Synthesis of the Naturally Occurring Antitumour Agent Irisquinone". Molecules 5: 82–88. doi:10.3390/50100082.