- Metal-ligand core-shell nanocomposite catalysts for the selective semihydrogenation of alkynes
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Catalysts with a sheltered upbringing: Novel core-shell nanocomposite catalysts consisting of active metal nanoparticles encapsulated by macroligands have been prepared. They have Pd nanoparticles (PdNPs) as an active core and shell ligands having sulfoxide moieties coordinated to the PdNPs. The shell protects the catalyst from coordination by alkenes and allows the lead-free selective semihydrogenation of a wide range of alkynes without any additives (see scheme). Copyright
- Mitsudome, Takato,Takahashi, Yusuke,Ichikawa, Satoshi,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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supporting information
p. 1481 - 1485
(2013/04/10)
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- Further explorations into the synthesis of Dehydro-Hedione
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Dehydrohedione (DHH) 1 may be obtained in 20% overall yield by a Reformatsky reaction with enone methyl ether 3b, followed by acidic workup of the crude reaction mixture. Alternatively, epoxidation (3-chloroperbenzoic acid, CH2Cl2, 84% yield) of the tertiary allyl alcohol derivative 4 affords a 1: 2 mixture of 8a and 8b. The latter epoxy ester 8b may also be obtained stereoselectively either from 4 (tBuO2H, [Mo(CO)6], 1,2-dichloroethane, 70°, 62% yield; or tBuO2H, [VO(acac)2], decane, 20°, 92% yield), or from 5 (AcOMe, LiN(SiMe3)2, THF, -78°, 84-87%). BF3×Et2O-Catalyzed cascade rearrangement and OH elimination of 8a afford selectively DHH 1 in 88% yield. The cis disposition of the side chains of the weakly odoriferous hedione-like analogues 2b and 2c was maintained by means of either an epoxy or a cyclopropane moiety. Copyright
- Winter, Béat,Chapuis, Christian,Brauchli, Robert,De Saint Laumer, Jean-Yves
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p. 246 - 258
(2013/03/28)
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- Rh-catalyzed highly enantioselective formation of functionalized cyclopentanes and cyclopentanones
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A catalyst system, [Rh(COD)Cl]2-BINAP-AgSbF6, has been developed as a second-generation catalyst for the cycloisomerization of 1,6-enynes tethered by carbon chains. Cyclopentanes and cyclopentanones, which can contain functional grou
- Liu, Fei,Liu, Qiang,He, Minsheng,Zhang, Xumu,Lei, Aiwen
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p. 3531 - 3534
(2008/09/19)
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- 1,4-Addition of chiral 2-propenylphosphonamide anions to α-substituted cyclopentenones: Use in enantioselective syntheses of methyl dihydrojasmonates and methyl jasmonates
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The addition of chiral 2-propenylphosphonamide anions, generated from the reaction products of (1R,2S)-ephedrine and 2-propene-1-phosphonyl dichloride, to α-substituted cyclopentenones is described. Ozonolysis of the addition products led to the synthesis of both enantiomers of methyl dihydrojasmonate and methyl jasmonate.
- Hailes, Helen C.,Isaac, Ben,Javaid
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p. 7325 - 7328
(2007/10/03)
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- Enantioselective synthesis of both enantiomers of methyl dihydrojasmonate using solid-liquid asymmetric phase-transfer catalysis
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Both enantiomers of methyl dihydrojasmonate (-)-1 and (+)-1 were obtained by a short route using asymmetric Michael addition of dimethyl malonate onto pentyl enone 3, followed by nonracemizing demethoxycarbonylation. The key enantioselective step involves a new system of asymmetric solid - liquid phase-transfer catalysis using solvent-free conditions. Enantiomeric excess as high as 90% (91% yield) was achieved.
- Perrard, Thierry,Plaquevent, Jean-Christophe,Desmurs, Jean-Roger,Hebrault, Dominique
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p. 2959 - 2962
(2007/10/03)
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