- ISOLATION AND TOTAL SYNTHESIS OF THE MAJOR CONSTITUENT OF THE ROOTS OF CENTAUREA INCANA: APLOTAXENE
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The major constituent of the petroleum ether extract of the root of Centaurea incana was identified as (8Z,11Z,14Z)-1,8,11,14-heptadecatetraene (Aplotaxene 1).A convergent and highly stereoselective synthesis of this compound is reported.
- Cossy, J.,Aclinou, P.
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- Catalytic decarbonylation of biosourced substrates
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Linear α-olefins (LAO) are one of the main targets in the field of surfactants, lubricants, and polymers. With the depletion of petroleum resources, the production of LAO from renewable feedstocks has gained increasing interest in recent years. In the present study, we demonstrated that Ir catalysts were suitable to decarbonylate a wide range of biosourced substrates under rather mild conditions (160 °C, 5 h reaction time) in the presence of potassium iodide and acetic anhydride. The resulting LAO were obtained with good conversion and selectivity provided that the purity of the substrate, the nature of the ligand, and the amounts of the additives were controlled accurately. The catalytic system could be recovered efficiently by using a Kugelrohr distillation apparatus and recycled.
- Ternel, Jérémy,Lebarbé, Thomas,Monflier, Eric,Hapiot, Frédéric
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- Amines as effective ligands in iridium-catalyzed decarbonylative dehydration of biosourced substrates
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Linear α-olefins (LAOs) and linear internal olefins (LIOs) are essential intermediates in the synthesis of surfactants, lubricants, and polymers. Concurrently with petroleum-based industrial processes, the production of LAOs and LIOs from renewable feedstocks has gained increasing interest in recent years. Organometallic catalysts have been developed designedly, especially Pd, Fe and Ir catalysts. However, such catalysts are mostly stabilized by phosphanes, ligands sometimes difficult to handle especially on large scales. Alternatives to phosphanes would thus be highly desirable. In the present study, we demonstrate that Ir catalysts coordinated by amines are suitable to decarbonylate a wide range of biosourced substrates under mild conditions. The resulting LAOs and LIOs are obtained with good conversion provided that the nature and the quantity of the amines are controlled accurately. The LAO/LIO selectivity can also be tuned by a judicious choice of experimental conditions. Interestingly, the Ir-based catalytic system is applicable to the decarbonylative dehydration of saturated, unsaturated and polyunsaturated fatty acids.
- Ternel, Jérémy,Léger, Bastien,Monflier, Eric,Hapiot, Frédéric
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- Synthesis and Spectroscopic Properties of Plant all-cis-Polyolefins
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Plant all-cis-polyolefins of the type 1a-c have been prepared by oxydative decarboxylation of the corresponding fatty acids or by synthesis starting with 1-chloro-4,7,10-tridecatriyne (5a) or 1-chloro-4,7-tridecadiyne (5b).Their spectroscopic properties are described.
- Boland, Wilhelm,Jaenicke, Lothar
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