TPAP

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TPAP
IUPAC name Tetrapropylammonium perruthenate
Identifiers
Abbreviations TPAP
TPAPR
CAS number [114615-82-6]
SMILES CCC[N+](CCC)(CCC)CCC.O=[Ru](=O)([O-])=O
Properties
Molecular formula C12H28NRuO4
Molar mass 351.43 g/mol
Appearance Green solid
Melting point

160 °C (decomposition)
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and 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 through a higher catalyst and co-oxidant loading along with the addition of two equivalents of water. The mechanism works by a normal oxidation of the alcohol to the aldehyde followed by hydration, and a final oxidation.[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.
Oxidation of alcohol to aldehyde with TPAP (0.06 eq.) and N-methylmorpholine N-oxide (1.7 eq.) with molecular sieves in dichloromethane.[4]


[edit] References

  1. ^ Review: Steven V. Ley, Joanne Norman, William P. Griffith, Stephen P. Marsden, "Tetrapropylammonium Perruthenate, Pr4N+RuO4−, TPAP: A Catalytic Oxidant for Organic Synthesis" Synthesis, 1994, 639. doi:10.1055/s-1994-25538
  2. ^ "Applications of Zr-Catalyzed Carbomagnesation and Mo-Catalyzed Macrocyclic Ring Closing Metathesis in Asymmetric Synthesis. Enantioselective Total Synthesis of Sch 38516 (Fluvirucin B1)" Z. Xu, C. W. Johannes, A. F. Houri, D. S. La, D. A. Cogan, G. E. Hofilena, A. H. Hoveyda, J. Am. Chem. Soc., 1997, 119, 10302
  3. ^ "Tetra-n-propylammonium perruthenate (TPAP)-catalysed oxidations of alcohols using molecular oxygen as a co-oxidant" Roman Lenz and Steven V. Ley. J. Chem. Soc., Perkin Trans. 1, 1997, 3291. doi:10.1039/C39870001625
  4. ^ A High-Yielding Synthesis of the Naturally Occurring Antitumour Agent Irisquinone John A. Hadfield, Alan T. McGown1 and John Butler Molecules 2000, 5, 82-88 Online Article
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