A general stereoselective method for the synthesis of cyclopropanecarboxylates. A new version of the homologous Horner–Wadsworth–Emmons reaction
作者:Henryk Krawczyk、Katarzyna Wąsek、Jacek Kędzia、Jakub Wojciechowski、Wojciech M. Wolf
DOI:10.1039/b712145h
日期:——
The synthesis of α-, β- and γ-substituted α-phosphono-γ-lactones was accomplished using different ring closure and ring homologation strategies. It was found that the lactones could be selectively transformed into the corresponding ethyl cyclopropanecarboxylates by treatment with sodium ethoxide in boiling THF. The reported reaction provides an attractive alternative to the classical homologous HornerâWadsworthâEmmons approach to the construction of cyclopropanes with electron-withdrawing functionalities.
Synthesis and cytotoxic activity of γ-aryl substituted α-alkylidene-γ-lactones and α-alkylidene-γ-lactams
作者:Anna Albrecht、Jacek F. Koszuk、Jakub Modranka、Marek Różalski、Urszula Krajewska、Anna Janecka、Kazimierz Studzian、Tomasz Janecki
DOI:10.1016/j.bmc.2008.03.035
日期:2008.5
A series of 5-aryl-3-alkylidenedihydrofuran-2(3H)-ones 6a-g'' and 11a,b as well as 5-aryl-3-methylidenepyrrolidin-2-ones 10a-c and 12 were synthesized starting from 4-aryl-2-diethoxyphosphoryl-4-oxobutanoates 3a-g. Reaction sequence includes reduction or reductiveamination of the carbonyl group, lactonization or lactamization step and finally the Horner-Wadsworth-Emmons olefination of aldehydes using