- CsF in organic synthesis. Inversion of secondary mesylates and tosylates
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Clean inversion of secondary mesylates and tosylates is effected by CsF in DMF. A variety of oxygen-, sulfur-, nitrogen-, and carbon-nucleophiles are employable. The reaction conditions have been optimized. The use of CsF in DMF is crucial and the reaction proceeds on the surface of solid CsF. It is suggested that hydrogen bonding between CsF and an active hydrogen of nucleophiles is responsible for the smooth reaction. Cesium carbonate fails to give rise to high specificity of inversion indicative of superiority of CsF.
- Otera, Junzo,Nakazawa, Koichi,Sekoguchi, Koichi,Orita, Akihiro
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p. 13633 - 13640
(2007/10/03)
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- Stereospecific and Stereoselective Reactions. V. Alkylation of Active Methylene Compounds by the Use of Alcohols, Diethyl Azodicarboxylate, and Triphenylphosphine
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The reagent formed by the reaction of diethyl azodicarboxylate (1) and triphenylphosphine (2) reacted with alcohols and ethyl cyanoacetate (6) to give alkylated products in 30 - 80percent yields.When ethyl acetoacetate, 1,3-1,3-coclopentanedione, or 1,3-cyclohexanedione was used in place of 6, the corresponding O-alkylated products were obtained.The reaction of either (S)-(-)-ethyl lactate or (S)-(-)-ethyl 2-hydroxy-3-phenylpropionate with 1, 2, and 6, followed by hydrolysis resulted in the formation of (S)-(-)-methylsuccinic acid or (S)-(-)-benzylsuccinic acid.The results indicate that nearly complete inversion of the configuration takes place in the alkylation step.
- Kurihara, Toshio,Sugizaki, Masaru,Kime, Itaru,Wada, Makoto,Mitsunobu, Oyo
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p. 2107 - 2112
(2007/10/02)
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