Ammonium eneselenolates: stereochemistry and electronic properties.
Ammonium eneselenolates: stereochemistry and electronic properties.
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烯烯醇酸铵：立体化学和电子特性。
DOI：
10.1021/jo015899x
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发表时间：
2001
影响因子：
3.6
通讯作者：
S. Kato
中科院分区：
文献类型：
--
作者：
T. Murai;S. Hayakawa;S. Kato
Ammonium eneselenolates were generated with high efficiency by reacting selenothioic acid S-esters with a THF solution of TBAF. The methylation of ammonium eneselenolates gave ketene selenothioacetals as stereoisomeric mixtures. The ratio of the two stereoisomers depended on the duration of the reaction before the addition of MeI. Ammonium eneselenolates were characterized by examining their (1)H, (13)C, and (77)Se NMR spectra, which indicated that ammonium eneselenolates were present almost exclusively as Z-isomers. These results suggested that ammonium eneselenolates are kinetically generated as stereoisomeric mixtures, and isomerization of E-isomers to Z-isomers then takes place to result in the exclusive formation of Z-isomers. During the methylation of Z-isomers of ammonium eneselenolates, the isomerization of Z-isomers to E-isomers occurs to give stereoisomeric mixtures of ketene selenothioacetals. NMR spectra of ammonium eneselenolates implied that the electrons at the selenium atom are somewhat delocalized to the carbon-carbon double bond and the carbon-selenium bond shows partial double-bond character.
