- Silicon-Assisted Synthesis of Thiocarbonyl Derivatives and Reactivity of Dienophilic Thioaldehydes
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Treatment of bis(trimethylsilyl) sulfide with CoCl2 * 6 H2O in the presence of aldehydes affords the corresponding thiocarbonyl analogues which can be trapped to avoid polymerization.The sulfurization reaction also takes place in the presence of TfOSiMe3, in which case, besides thioaldehydes, thioketones may be obtained in satisfactory yields.When thioaldehydes are generated with the CoCl2 * 6 H2O method the Diels-Alder reaction with cyclohexadiene occurs with very high selectivity in favor of the endo isomer, whereas when the TfOSiMe3-based method is employed, the stereochemistry of the cycloadduct can be conveniently selected toward endo or exo by varying the molar ratio of the sulfurating agent.
- Capperucci, Antonella,Degl'Innocenti, Alessandro,Ricci, Alfredo,Mordini, Alessandro,Reginato, Gianna
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p. 7323 - 7328
(2007/10/02)
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- Synthesis and properties of substituted α'-lithiated α(Z),γ-butadienyl sulfoxides. Part I : Structural studies on sulfoxides obtained by stereospecific cyclisation of these compounds.
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The lithio-derivatives of sulfoxides 2b,c were prepared and gave stereospecifically after protonation the 2β-substituted 3,6-dihydro-4-methyl-2H-thiopyran-1α-oxides 3b,c.The latter were converted into the 1β-oxide 9b, the 2-substituted 3,6-dihydro-4-methyl-2H-thiopyrans 8b,c and the corresponding sulfones 10b,c.By comparison of the NMR spectra of these compounds as well as the effects of solvent (benzene) and europium salts on the chemical shifts of sulfoxides, the trans orientation of the sulfoxide group and R for 3b,c has been established.
- Reglier, M.,Julia, S. A.
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p. 226 - 235
(2007/10/02)
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- ON THE PROPERTIES OF SOME SUBSTITUTED α'-LITHIATED α(Z),Y-BUTADIENYL SULFIDES: CYCLISATIONS AND REARRANGEMENTS
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The conditions for the preparation and cyclisation of the title compounds 3 are described.The stability of the intermediate lithio-thiacyclohexenes 4 is shown to depend on the reaction conditions and the substituents R1-R4.The final Products 6, 10 and 7 arise from 4 via sigmatropic rearrangement, a prototropic shift followed by a sigmatropic rearrangement, or the elimination of lithium methanethiolate respectively.
- Reglier, Marius,Julia, Sylvestre A.
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p. 2319 - 2322
(2007/10/02)
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- STEREOSELECTIVE CONVERSION OF LITHIATED BENZYLIC OR ALLYLIC 3-METHYL-1(Z),3-BUTADIENYL SULFIDES INTO CIS-DISUBSTITUTED CYCLOPROPANE COMPOUNDS
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The lithio-thiacyclohexenes 6 are intermediates in the title conversion 4 9.
- Reglier, Marius,Julia, Sylvestre A.
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p. 2387 - 2390
(2007/10/02)
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