The Synthesis and Configurational Stability of Enantioenriched α-Thioallyllithium Compounds and the Stereochemical Course of Their Electrophilic Substitution
chiral lithium compounds. The α-thioallyllithium compounds 9 and 25 were found to be configurationally stable in THF solutions at −78 °C. These represent the first configurationally stable α-thio-substituted allyllithium compounds, and they can be utilized in asymmetric synthesis. Alkylations proceeded with stereoinversion or in an anti-SE′ process, while addition to carbonyl compounds took place in
对映体富集的S-烯丙基N-单烷基单硫代氨基甲酸酯的质子化提供了相应的手性锂化合物。发现α-硫代烯丙基锂化合物9和25在-78℃下在THF溶液中是构型稳定的。这些代表第一构型稳定的α-硫代取代的烯丙基锂化合物,它们可用于不对称合成中。烷基化以立体反转或抗-S E '过程进行,而羰基化合物的添加以顺-S E '过程进行。羟烷基化产物用作Ni 0的起始原料-催化的交叉偶联反应。
Palladium(0) catalyzed enantioselective rearrangement of O-allylic thiocarbamates to S-allylic thiocarbamates: asymmetric synthesis of allylic thiols
作者:Achim Böhme、Hans-Joachim Gais
DOI:10.1016/s0957-4166(99)00263-3
日期:1999.7
The Pd(0) catalyzed rearrangement of the O-allylic thiocarbamates rac-2a, rac-2b and rac-4 in the presence of the chiral bisphosphane 5 proceeded quantitatively and gave the S-allylic thiocarbamates 6a, 6b and 7, respectively, with 91, 92 and 97% ee, respectively, in high yields. Saponification of the S-allylic thiocarbamate 7 furnished the allylic thiol 9 with 97% ee. (C) 1999 Elsevier Science Ltd. All rights reserved.
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作者:O. G. Bondarev、K. N. Gavrilov、V. N. Tsarev、V. A. Davankov、H.-J. Gais
DOI:10.1023/a:1021324126769
日期:——
New quinine-based polyfunctional aryl phosphite was synthesized. The phosphorus center in the new compound is characterized by a large cone angle (theta = 190). The new compound can be used in the Pd-catalyzed enantioselective rearrangement of cyclic O-allylic thiocarbamate into S-allylic thiocarbamate in an optical yield of up to 47% with a quantitative conversion.