Iron-Catalyzed Michael Reactions - From Experiment to Theory and Back
Institut für Reine und Angewandte Chemie der Universität Oldenburg, Carl von Ossietzky-Str. 9-11, Oldenburg 26111, Germany
The catalysis of Michael reactions by FeCl3 · 6 H2O is an environmentally sound alternative to classical base catalysis . A number of β-diketones and β-oxo esters are cleanly converted with methyl vinyl ketone to the corresponding Michael reaction products within a few hours at ambient temperature with quantitative yields being achieved in most cases. The reaction can be performed solvent free and without any need for anhydrous or inert conditions. Due to quantitative chemoselectivity, work-up and purification are very simple. Iron compounds are readily available, and with respect to economical and environmental considerations, it is the transition metal catalyst of choice. Starting materials are converted stoichiometrically and atom-economically without any need of reagents or even solvents and without generation of any by-product.
We have investigated the mechanism of this process by X-ray absorption and Raman spectroscopy , ESI-MS spectrometry as well as kinetic studies and DFT-calculations . Actually, a strong anion-dependence of the catalytic activity was predicted by our spectroscopic and theoretical studies which led to the development of a new catalyst system being about 10 times more active than FeCl3 · 6 H2O.
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 S. Pelzer, T. Kauf, C. van Wüllen, J. Christoffers, J. Organomet. Chem. 2003, 684, 308-314.
Presentation: oral at 18th Conference on Physical Organic Chemistry, Symposium 2, by Jens Christoffers
See On-line Journal of 18th Conference on Physical Organic Chemistry
Submitted: 2006-05-01 08:45 Revised: 2009-06-07 00:44
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