- Enantioselective Michael-Mukaiyama Additions of Silylketene acetals to 2-Carboxycyclopentenones Promoted by Chiral Ti Complexes.
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The conjugate addition of t-butylpropionate silylketeneacetal 2 to 2-carboxycyclopentenones 3a-b promoted by TADDOL-derived Ti chlorides gives the ketoacid 6 with excellent d.e. and e.e. up to 47percent.
- Bernardi, Anna,Karamfilova, Katia,Boschin, Giovanna,Scolastico, Carlo
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- Chiral ligand-controlled asymmetric conjugate addition of α-trimethylsilanylacetate to acyclic and cyclic enones
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The reaction of lithium ester enolate with enones provides a challenge for chemoselectivity, that is, discrimination between a conjugate addition and a 1,2-addition. Asymmetric conjugate addition of a lithium enolate of α-trimethylsilanylacetate to acyclic and cyclic α,β-unsaturated ketones was mediated by an external chiral ligand to give the corresponding 1,4-adducts in good enantioselectivity of 74% and good chemoselectivity.
- Iguchi, Mayu,Doi, Hirohisa,Hata, Seiji,Tomioka, Kiyoshi
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- Anodic Oxidation of Norcamphor in Aqueous Electrolytes
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Norcamphor (1) was anodically oxidized at Pb/PbO2 anodes in 1 M*H2SO4, MeCN/H2O (V/V = 1/1). 3-Oxocyclopentaneacetic acid (3) and oxabicyclooctan-3-one (4) were obtained with material yields up to 76percent and 42percent, respectively.The effects of electrode materials, current densities and concentrations were studied.A possible anodic oxidation mechanism was proposed.
- Ye, Siyu,Beck, F.
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- Facile Synthesis of Spirocyclic Lactams from β-Keto Carboxylic Acids
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A facile synthesis of spirocyclic lactams starting from β-keto carboxylic acids via a one-pot cascade reaction involving a Curtius rearrangement and an intramolecular nucleophilic addition of the enol carbon to the isocyanate intermediate is reported. The same conditions have also been used for the generation of fused cyclic lactams with similar good yields. The synthetic value of this method has been demonstrated by efficient synthesis of tetracyclic spirolactam 8 and pentacyclic spirolactam 9.
- Yang, Wei,Sun, Xianyu,Yu, Wenbo,Rai, Rachita,Deschamps, Jeffrey R.,Mitchell, Lauren A.,Jiang, Chao,Mackerell, Alexander D.,Xue, Fengtian
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supporting information
p. 3070 - 3073
(2015/06/30)
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- Heterogeneous platinum catalytic aerobic oxidation of cyclopentane-1,2- diols to cyclopentane-1,2-diones
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A method for the aerobic oxidation of cyclopentane-1,2-diols to the corresponding diketones over a commercial heterogeneous Pt/C catalyst is described. Unsubstituted and 3- or 4-substituted cyclopentane-1,2-diols are oxidized to 1,2-dicarbonyl compounds in good yields under the reported optimized reaction conditions (atmospheric air, 1 mol % of catalyst, 1 equiv of LiOH, aqueous solvents and 60 °C temperature). The method is applicable for producing cyclopentane-1,2-diketones in a scalable manner.
- Reile, Indrek,Kalle, Sigrid,Werner, Franz,J?rving, Ivar,Kudrjashova, Marina,Paju, Anne,Lopp, Margus
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p. 3608 - 3613
(2014/05/20)
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- Synthesis of 3- and 4-Substituted Cyclic α-Amino Acids Structurally Related to ACPD
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The preparation of 3-substituted cyclopentanones 12-16, 4-substituted cyclohexanones 23-28 and cycloheptanones 38-41 is described.Substituents in the cycloalkanones are carboxylate, phosphonate or tetrazole groups, separated from the ring by a 0, 1, 2, or 3 carbon atoms chain.These cycloalkanones have been transformed into α-amino acids 9-11 by hydrolysis of the corresponding hydantoin derivatives 21, 37 and 62, obtained under Bucherer-Bergs reaction conditions.
- Alonso, Francisco,Mico, Irene,Najera, Carmen,Sansano, Jose M.,Yus, Miguel,et al.
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p. 10259 - 10280
(2007/10/02)
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- Syntheses of Jasmonic Acid Related Compounds and Their Structure-Activity Relationships on the Growth of Rice Seedings
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Jasmonic acid (JA)-related compounds were synthesized, and their inhibitory activities on rice seedling growth were investigated.Three functions (C-1 CH2COOH or CH2COOCH3, C-2 (Z)-2'-pentenyl or n-pentyl and C-3 ketone or hydroxyl) were essential for exhibiting inhibitory activity in this series of compounds.A dihydro-JA-related compound, 4-acetylnonanoic acid, also showed inhibitory activity similar to JA.
- Yamane, Hisakazu,Sugawara, Jun,Suzuki, Yasushi,Shimamura, Etsuko,Takahashi, Nobutaka
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p. 2857 - 2864
(2007/10/02)
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