m3-Oxohexakis(m-trimethylacetato)tris(methanol)triiron(III) Chloride


[55216-31-4]  · C33H66ClFe3O16  · m3-Oxohexakis(m-trimethylacetato)tris(methanol)triiron(III) Chloride  · (MW 921.99)

(one of several (m3-oxo)triiron cluster complexes used to catalyze the epoxidation of alkenes with molecular oxygen1)

Physical Data: orange-yellow crystalline solid.

Preparative Methods: equimolar aqueous solutions of FeIIICl3 and sodium pivalate are mixed and the resulting precipitate is filtered and dried in vacuo.2

Purification: recrystallization from chloroform-methanol.

Epoxidation of Alkenes.3

[Fe3O(OPiv)6(MeOH)3]+Cl- (Piv = OCCMe3) is a useful catalyst for the epoxidation of alkenic alcohol acetates with molecular oxygen. The reaction requires one equivalent of oxygen to effect the peroxidation, half of which is apparently consumed in undesirable side reactions. The regiospecificity of the oxidation is similar to that observed when conventional peroxy acid epoxidation reagents are used,4 but is opposite to that observed under Sharpless epoxidation conditions.5 This polynuclear transition metal catalyst affords higher yields and better selectivity than alternative transition metal catalysts known to effect alkene epoxidation with oxygen. However, two particularly good alternatives are [Fe3O(OAc)6(H2O)3](OAc) [60797-92-4] and [Fe3O(OAc)6(py)3]Cl [69554-73-0].6 Mononuclear iron catalysts, such as FeCl3, failed under the prescribed conditions. Depending on the substrate, the reaction may be performed in the absence of a solvent. For instance, 6,7-epoxygeranyl acetate was produced from geranyl acetate in the absence of a solvent (60 °C, 20 h) and without formation of the 2,3-epoxide isomer (eq 1).

1. Hiatt, R. In Oxidation; Augustine, R. L.; Trecker, D. J., Eds.; Dekker: New York, 1971; Vol. 2. (b) Sharpless, K. B.; Verhoeven, T. R. Aldrichim. Acta 1979, 12, 63.
2. Blake, A. B.; Fraser, L. R. JCS(D) 1975, 193.
3. Ito, S.; Inoue, K.; Mastumoto, M. JACS 1982, 104, 6450.
4. Moesseron-Canet, M.; Mousseron, M.; Levallois, C. BSF 1964, 297.
5. Sharpless, K. B.; Michaelson, R. C. JACS 1973, 95, 6136.
6. Earnshaw, A.; Figgis, B. N.; Lewis, J. JCS(A) 1966, 1656.

Mark W. Zettler

The Dow Chemical Company, Midland, MI, USA

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