Base-Catalyzed Ethanolysis of α-Diethoxyphosphoryl-γ-lactones: A Facile Synthesis of Cyclopropanecarboxylates
作者:Henryk Krawczyk、Katarzyna Wąsek、Jacek Kędzia
DOI:10.1055/s-2005-917116
日期:——
A range of alkyl- and alkenylcyclopropanecarboxylic acid ethyl esters has been stereoselectively prepared by treatment of substituted α-diethoxyphosphoryl-y-lactones with sodium ethoxide in tetrahydrofuran.
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.
Diastereoselective Synthesis of the ABCD Ring System of Rubriflordilactone B
作者:David A. Nicewicz、Hudson G. Roth
DOI:10.1055/a-1659-6521
日期:2022.1
A novel 9-step diastereoselective route to the ABCD ringsystem of the natural product rubriflordilactone B is reported. Use of an a-substituted butenolide derived from maleic anhydride facilitated a 1,4-conjugate addition to provide a diene. The order in which a ring-closing metathesis and enolate oxidation were performed on this compound dictate the relative stereochemistry of the target. The final
报道了一种新的 9 步非对映选择性途径,用于天然产物 rubriflordilactone B 的 ABCD 环系统。使用衍生自马来酸酐的α-取代的丁烯内酯促进了1,4-共轭加成以提供二烯。对该化合物进行闭环复分解和烯醇氧化的顺序决定了目标的相对立体化学。最终产品在室温 NMR 研究期间表现出各向异性效应,需要高温实验来确认其身份。