Transition-metal trifluoromethane-sulphonates-recyclable catalysts for the synthesis of branched fatty derivatives by Diels-Alder reactions at unsaturated fatty esters
✍ Scribed by Arno Behr; Martin Fiene; Franz Naendrup; Klaus Schürmann
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 162 KB
- Volume
- 102
- Category
- Article
- ISSN
- 1438-7697
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✦ Synopsis
Transition-metal trifluoromethane-sulphonatesrecyclable catalysts for the synthesis of branched fatty derivatives by Diels-Alder reactions at unsaturated fatty esters
Diels-Alder reactions of conjugated linoleic acid ethyl ester (1) with different quinones and with a variety of α/β-unsaturated aldehydes and ketones are described in this paper. Using Sc(OTf) 3 or Cu(OTf) 2 as catalysts the reactions can be carried out at 25-40 °C with good yields. For the first time in oleochemistry it is possible to prepare Diels-Alder cycloadditions with catalyst concentrations of 10 mol-% instead of stoichiometric amounts of Lewis acids. Furthermore, the reaction time was partly shortened drastically. The catalyst Sc(OTf) 3 can be removed by a simple extraction of the organic layer with water. After evaporation of the aqueous phase to dryness the catalyst can be reused without loss of yield.