- Palladium-Catalyzed Chemoselective Protodecarboxylation of Polyenoic Acids
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Conditions for the first palladium-catalyzed chemoselective protodecarboxylation of polyenoic acids to give the desired polyenes in good yields are presented. The reactions proceed under mild conditions using either a Pd(0) or Pd(II) catalyst and tolerate a variety of aryl and aliphatic substitutions. Unique aspects of the reaction include the requirement of phosphines, water, and a polyene adjacent to the carboxylic acid.
- Al-Huniti, Mohammed H.,Perez, Mark A.,Garr, Matthew K.,Croatt, Mitchell P.
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supporting information
p. 7375 - 7379
(2019/01/03)
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- A general and efficient aldehyde decarbonylation reaction by using a palladium catalyst
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A facile decarbonylation reaction of aldehydes has been developed by employing Pd(OAc)2. A wide variety of substrates are decarbonylated, without using any exogenous ligand for palladium as well as CO-scavenger.
- Modak, Atanu,Deb, Arghya,Patra, Tuhin,Rana, Sujoy,Maity, Soham,Maiti, Debabrata
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supporting information; experimental part
p. 4253 - 4255
(2012/05/04)
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- Synthesis of C40-symmetrical fully conjugated carotenoids by olefin metathesis
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In an effort to push olefin metathesis to the limits of conjugation in reactants and products, the C40-symmetrical carotenoids β,β-carotene (1), lycopene (2), (3R,3′R)-zeaxanthin (3), and rac-isozeaxanthin (4), which are conjugated undecaenes, have been synthesized from C21-terminal hexaenes by treatment with Grubbs' second-generation Ru catalyst in dichloromethane at 50 °C.
- Fontan, Noelia,Dominguez, Marta,Ulvarez, Rosana,De Lera, Ungel R.
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p. 6704 - 6712
(2012/01/03)
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- A survey of mono- or bis-decarboxylation of β-methyl polyethylenic-malonic acids
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Diverse experimental conditions, leading to mono- or bis-decarboxylation of β-methyl polyethylenic-malonic acids, were examined. A clean and easy bis-decarboxylation was reported.
- Valla, Alain,Le Guillou, Régis,Cartier, Dominique,Labia, Roger
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p. 4737 - 4740
(2007/10/03)
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- Highly selective synthesis of vitamin A and its derivatives. Critical comparison of some known palladium-catalyzed alkenyl-alkenyl coupling reactions
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Vitamin A has been synthesized cleanly and selectively with essentially complete control of stereo- and regiochemistry in four linear and six overall steps from β-ionone and (E)-3-methyl-2-penten-4-yn-1-ol via Pd-catalyzed cross coupling of an alkenylzinc with an alkenyl iodide; the use of other metals, such as Al, Zr, Mg, B, Cu, and Sn, being inferior to that of Zn.
- Negishi,Owczarczyk
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p. 6683 - 6686
(2007/10/02)
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- SYNTHETIC INVESTIGATIONS IN THE CHEMISTRY OF POLYENE COMPOUNDS. -- XLVIII. STRUCTURE AND TRANSFORMATIONS OF 12-CARBOXYRETINOIC ACIDS AND THEIR ESTERS. SYNTHESIS OF 13-CIS-RETINOIC ACID
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In reaction with ethyl β-methylglutaconate under the influence of alkali in methanol the Z and E isomers of β-ionylideneacetaldehyde form isomeric 9Z,11Z,13Z- and 9E,11Z,13Z-12-carboxyretinoic acids.Decarboxylation of the latter in the pyridine-piperidine system in the presence of copper salts leads to 13Z-retinoic acid and is accompanied by the formation of 9,13-dimethyl-7-(1,1,5-trimethyl-5-cyclohexen-6-yl)-7,9,11,13-octatetraene.The stereoisomeric transformations of 12-substituted 9E,Z,11Z,13Z-retinoic acids and the corresponding diols and diacetates obtained from them were investigated.Isomerization takes place at the double bond at the C9 atom and depends on the nature of the substituent at the C12 atom.
- Polyachenko, L. N.,Davydova, L. P.,Darskaya, E. N.,Filippova, T. M.,Samokhvalov, G. I.
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p. 685 - 694
(2007/10/02)
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