Malonic Ester Synthesis. Side reactions

Quote: Originally posted by TheRealKP

FrankMartin, You should add the sodium ethoxide solution slowly with a pressure-equalized addition funnel, and keep the reaction concentration low. Whatever else you do depends upon the R group that you are using. Basically then it comes down to a kinetic versus thermodynamic approach. I was trained in a lab with students who worked on exactly the same reaction and they seemed to have succeeded in obtaining the ME-R species. Thanks you. My setup attached. I understood the alkylhalide was the one to be added slowly following Vogel & OrgSyn. Strangely there is no exothermmic reaction when the halide is slowly added, and about 10hr is required for the alkalinity of the mixture to reduce to give a "neutral litmus'' test. Do you say the ethoxide is the one to be added to the other reactants? Nothing in Vogel or OrgSyn says this, and I've seen it only in very early patents. KP

Quote: Originally posted by Sigmatropic

The best conditions to maximize the first reaction is to completely suppress the second reaction by using a non nucleophilic base. I've done enolate alkylation using LDA but there are a myriad of sterically hindered bases and things like the alkali hydrides which would work equally well. Perhaps even something such as potassium tert butoxide would work.