Synthesis and characterization of permethylated 1,3,5-tri- and 1,3,5,7-tetracarbonyl compounds
作者:Silke Erfle、Thomas Rahn、Franziska Bendrath、Wolfgang Baumann、Dirk Michalik、Haijun Jiao、Anke Spannenberg、Armin Börner、Peter Langer
DOI:10.1016/j.tet.2011.08.065
日期:2011.11
Permethylated 1,3,5-tri- and 1,3,5,7-tetracarbonyl compounds were prepared and structurally characterized. 2,2,4,4-Tetramethyl-3,5-dioxoesters were prepared by condensation of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with acid chlorides and subsequent reaction with methyl iodide. 2,2,4,4,6,6-Hexa-substituted 3,5-dioxopimelates were prepared by condensation of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with methyl 3-chloro-3-oxopropanoate and subsequent methylation. The use of caesium carbonate as the base for the methylation proved to be important to achieve good yields. The conformation of the products was studied by experimental and theoretical methods (DFT calculations). (C) 2011 Elsevier Ltd. All rights reserved.