Herein, we report the first and efficient asymmetric totalsynthesis of the neurotoxin (−)-caramboxin. The key to success is the creation of a stereogenic center by using enantioselective catalytic phase-transfer α-alkylation of glycine imines, affording this unusual α-amino acid in good yields and up to 99% ee. This work validates the S configuration of the natural product.
在此,我们报告了神经毒素 (−)-caramboxin 的第一个有效的不对称全合成。成功的关键是通过使用甘氨酸亚胺的对映选择性催化相转移 α-烷基化来创建立体中心,从而以良好的产率和高达 99% ee 提供这种不寻常的 α-氨基酸。这项工作验证了天然产物的S构型。
Schneider; Gramms, Chemische Berichte, 1936, vol. 69, p. 2543,2555
作者:Schneider、Gramms
DOI:——
日期:——
Study of the state of rhodium in the potassium rhodiumundecatungstosilicate/alumina system by diffuse-reflectance IR spectroscopy
作者:P. A. Korovchenko、R. A. Gazarov、L. M. Kustov
DOI:10.1007/bf02495757
日期:2000.7
Adsorption of CO on the catalytic system K-5[SiW11RhO39]/Al2O3 was studied by diffuse-reflectance IR spectroscopy. The electronic state of rhodium and thermal stability of the system in the redox cycles were studied. The oxidized heteropolycompound (HPC) contains the charged forms Rh+, Rh2+, and Rh3+. Their ratio strongly depends on the pre-treatment temperature of the sample. In the reduced HPC two main forms of rhodium exist: the ionic Rh+ and metallic Rh-0. The supported HPC structure is stable in an oxidative medium at temperatures below -900 K. The properties of the K-5[SiW1 1RhO39]/Al2O3 system are retained in the redox cycles up to -670 K, and the highly dispersed state of rhodium is observed up to 900 K.
Synthesis of 2,4,6-triaryl-1-selenacyclohexane-2,6-diselenols
作者:V. G. Kharchenko、B. I. Drevko
DOI:10.1007/bf00526097
日期:1982.5
Kharchenko, V. G.; Drevko, B. I., Journal of Organic Chemistry USSR (English Translation), 1982, vol. 18, p. 2290 - 2291