- Substituent Effects in Parallel-Displaced π–π Stacking Interactions: Distance Matters
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Host–guest systems with Rebek imide type receptors and a 2,6-di(isobutyramido)pyridine ligand were employed to investigate substituent effects in parallel-displaced π–π stacking interactions. Changing the intermolecular distance between the para substitue
- Riwar, Leslie-Joana,Trapp, Nils,Kuhn, Bernd,Diederich, Fran?ois
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supporting information
p. 11252 - 11257
(2017/09/02)
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- 3,5,7-Trimethyl-1-azatricyclo[3.3.1.13,7]decan-2-ylidene, an Aminocarbene without π conjugation
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3,5,7-Trimethyl-1-azatricyclo[3.3.1.13,7]decan-2-ylidene, an aminocarbene without π conjugation, has been generated from the corresponding tosylhydrazone salt. Addition of the carbene to alkenes is stereospecifically cis, thus showing that the
- Ye, Qing,Komarov, Igor V.,Kirby, Anthony J.,Jones Jr., Maitland
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p. 9288 - 9294
(2007/10/03)
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- A conformational study of cyclohexane-1,3,5-tricarbonitrile derivatives
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Cyclohexane-1,3,5-tricarbonitrile reached equilibrium having 1,3-cis-1,5-cis and 1,3-cis-1,5-trans isomers in a ratio of 3:7. The cis,cis-isomer preferred the conformation with three equatorial cyano groups, whereas the cis,trans-isomer displayed two cyano groups on equatorial positions and another cyano group on axial position. Condensation of cis,cis-cyclohexane-1,3,5-tricarbonitrile with L-(S)-valinol by the catalysis of ZnCl2 in refluxing 1,2-dichlorobenzene afforded two isomeric cyclohexane-1,3,5-trioxazolines in favor of the 1,3-cis-1,5-trans isomer. Metalation of cis,cis-cyclohexane-1,3,5-tricarbonitrile, followed by alkylations with dimethyl sulfate, benzyl bromide or allyl bromide, gave the corresponding trialkylation products with predominance of 1,3-cis-1,5-trans isomers. The cis,trans-isomer showed two cyano groups on axial positions and another cyano group on equatorial position, whereas the cis,cis-isomer exhibited three axial cyano groups. Treatment of trimethyl cis,cis-cyclohexane-1,3,5-tricarboxylate with lithium diisopropylamide and dimethyl sulfate afforded mainly the trimethyl ester of Kemp's triacid, which showed three axial carboxylate groups. Two competitive factors, i.e. the steric effect of incoming electrophiles and the dipole-dipole interactions of the cyano or carboxylate groups, might interplay to give different stereoselectivities in these reaction systems.
- Chuang, Tsung-Hsun,Fang, Jim-Min
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p. 193 - 200
(2007/10/03)
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- Synthesis and Conformational Analysis of cis,cis-1,3,5-Trimethylcyclohexane-1,3,5-tricarboxylic Acid
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Conversion of 3,5,7-trimethyladamantan-1-ol to a hypobromite, fragmentation in situ, and oxidation with KMnO4 generate the lactone, 6, of cis,cis-1,3,5-trimethyl-1-(hydroxymethyl)cyclohexane-3,5-dicarboxylic acid, which can in turn be oxidized by RuO4-HIO
- Kemp, D. S.,Petrakis, Konstantinos S.
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p. 5140 - 5143
(2007/10/02)
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