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Transition‐metal trifluoromethane‐sulphonates‐recyclable catalysts for the synthesis of branched fatty derivatives by Diels‐Alder reactions at unsaturated fatty esters
Author(s) -
Behr Arno,
Fiene Martin,
Naendrup Franz,
Schürmann Klaus
Publication year - 2000
Publication title -
european journal of lipid science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.614
H-Index - 94
eISSN - 1438-9312
pISSN - 1438-7697
DOI - 10.1002/(sici)1438-9312(200005)102:5<342::aid-ejlt342>3.0.co;2-j
Subject(s) - chemistry , catalysis , yield (engineering) , organic chemistry , diels–alder reaction , lewis acids and bases , lewis acid catalysis , materials science , metallurgy
Diels‐Alder reactions of conjugated linoleic acid ethyl ester (1) with different quinones and with a variety of α/βunsaturated 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.