J. Chen, L.K. Woo / Journal of Organometallic Chemistry 601 (2000) 57–68
67
Acknowledgements
We thank Professor Ged Parkin for a generous gift
of potassium hydrotris(3-tbutylpyrazol-1-yl)borate. We
are grateful to the Iowa Soybean Promotion Board and
the Camille and Henry Dreyfus Foundation for partial
support of this work.
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4. Conclusions
Several monomeric manganese and iron complexes
with sterically demanding tetradentate trisamidoamines
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selectivity using PhIO as oxidant, while the analogous
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and 6 were employed as catalysts, in comparison to
control experiments where no metal complex was used.
Complex 4 was the most efficient catalyst with a yield
of styrene oxide as high as 89% in 2.5 h. The metal
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of the ligands was not sufficient to prevent m-oxo
deactivation, or that the ligand itself decomposed grad-
ually during the epoxidation reactions. From a discus-
sion of the epoxidation mechanism, it is likely that the
catalyst enhances the formation of an acylperoxy radi-
cal. Moreover, the high selectivity for epoxide product
suggests that a metal complex must be involved directly
in the epoxidation step.
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