74888-97-4Relevant articles and documents
Phosphinoalkylnitriles: Synthesis and coordination behaviour at palladium centres
Pitter, Stephan,Dinjus, Eckhard,Jung, Beate,Go?rls, Helmar
, p. 934 - 946 (2007/10/03)
Phosphinoalkylnitriles R2P-(CH2)n-CN {R = isopropyl (ipr), phenyl (ph), cyclohexyl (chex), n = 3, 6, 10} have been prepared starting from the corresponding secondary phosphines in an easy three step synthesis. All new compounds were characterized by their 1H-, 13C and 31P NMR data. Some of these new P, N ligands were used to prepare complexes [{R2P-(CH2)n-CN}2PdCl2] which were also identified by their NMR data. In addition the crystal structures of three derivatives, [{ipr2P-(CH2)3-CN} 2PdCl2] 7a, [{ph2P-(CH2)3-CN}2PdCl2] 7b and [{ph2P-(CH2)6-CN}2PdCl2] 8b were determined by X-ray analysis. The coordination mode of the phosphinoalkylnitriles in these complexes was found to be P-bonded resulting in a trans configuration. Palladium catalysts with 5a as ligund show high activies in the co-oligomerization of butadiene and carbon dioxide. The δ-lactone 11a is formed under very mild conditions.
THE SYNTHESIS OF ORGANIC CHEMICALS BY CATALYTIC REACTIONS OF CARBON DIOXIDE
Behr, Arno
, p. 671 - 684 (2007/10/02)
Different reactions are discussed in which carbon dioxide adds to unsaturated hydrocarbons after activation by transition metal catalysts.Alkynes react in the presence of nickel or rhodium complexes to yield substituted pyrones.Alkenes are also described to react with CO2 yielding acids and esters; however,the proof, that carbon dioxide is really involved in this reaction, is still lacking.The best studied reaction is the chemistry of carbon dioxide and butadiene.Using palladium, nickel and ruthenium catalysts γ- and δ-lactones are formed by the reaction of two molecules of butadiene and one molecule of CO2.The catalyst and the reaction parameters could be optimized thus enabling the synthesis of the δ-lactone in an industrial scale.A mechanism is proposed in which a carboxylate complex is discussed to be key intermediate, and a similar palladium complex could be isolated in a related stoichiometric experiment.Using rhodium catalysts, a γ-lactone is formed in which three molecules of butadiene are connected to one molecule of carbon dioxide.Also the co-reaction of butadiene, isoprene and CO2 yields novel lactones.All these products may become of interest as fine chemicals, for instance fragrances.Another possible use of the lactones is their conversion into open-chained products.The splitting of the δ-lactone yields new carboxylic acids and esters with hydroxy or methoxy substituents, which may become useful starting molecules for chemical syntheses.
PALLADIUM-CATALYZED REACTION OF BUTADIENE AND CARBON DIOXIDE
Behr, Arno,Juszak, Klaus-D.
, p. 263 - 268 (2007/10/02)
The selective syntheses of the δ-lactone 2-ethylidene-6-hepten-5-olide and of the γ-lactone 2-ethyl-2,4-heptadien-4-olide by the palladium-catalyzed reaction of carbon dioxide and butadiene are described.Mechanistic studies showed that the formation of the γ-lactone proceeds by a consecutive reaction via the δ-lactone.The products are accounted for in terms of a reaction path involving an allylic palladium carboxylate complex as a key intermediate.
