Selective conversion of polyenes to monoenes by RuCl(3) -catalyzed transfer hydrogenation: the case of cashew nutshell liquid.
Cardanol, a constituent of cashew nutshell liquid (CNSL), was subjected to transfer hydrogenation catalyzed by RuCl(3) using isopropanol as a reductant. The side chain of cardanol, which is a mixture of a triene, a diene, and a monoene, was selectively reduced to the monoene. Surprisingly, it is the C8-C9 double bond that is retained with high selectivity. A similar transfer hydrogenation of linoleic acid derivatives succeeded only if the substrate contained an aromatic ring, such as a benzyl ester. TEM and a negative mercury test showed that the catalyst was homogeneous. By using ESI-MS, ruthenium complexes were identified that contained one, two, or even three molecules of substrate, most likely as allyl complexes. The interaction between ruthenium and the aromatic ring determines selectivity in the hydrogenation reaction.
Stratingh Institute of Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Sébastien
S
Perdriau
Sjoerd
S
Harder
Hero J
HJ
Heeres
Johannes G
JG
de Vries
D019840:2-Propanol / Q000737:chemistry; D031021:Anacardium / Q000737:chemistry*; D002384:Catalysis; D006865:Hydrogenation; D019787:Linoleic Acid / Q000737:chemistry; D015394:Molecular Structure; D009754:Nuts / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry* / Q000302:isolation & purification; D011090:Polyenes / Q000737:chemistry*; D017975:Ruthenium Compounds / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
D010636:Phenols; D011090:Polyenes; D017975:Ruthenium Compounds; C038590:cardanol; D019787:Linoleic Acid; D019840:2-Propanol; C038365:ruthenium chloride