77028-68-3Relevant academic research and scientific papers
Enecarboxylation with Diethyl Oxomalonate as an Enophilic Equivalent of Carbon Dioxide. A Synthesis of Allylcarboxylic Acids
Salomon, Mary F.,Pardo, Simon N.,Salomon, Robert G.
, p. 3797 - 3802 (2007/10/02)
Allylcarboxylic acids are prepared from alkenes by a two-stage process which is synthetically equivalent to an ene reaction of carbon dioxide: (1) ene reaction with diethyl oxomalonate to afford an α-hydroxylmalonic ester and (2) oxidative bisdecarboxylation of the derived α-hydroxymalonic acid.The oxidative bisdecarboxylation of α-hydroxymalonic acids can sometimes be achieved with sodium periodate.However, occasionally decarboxylation is only partial, leading to pyruvic rather than carboxylic acids.While the bisdecarboxylations with periodate have previously been "buffered with a little pyridine", the latter is now shown to inhibit the reaction.In fact the pyruvate:carboxylate ratio can be a sensitive function of the amount of pyridine present in the reaction mixture, and the oxidative decarboxylation can be controlled to yield almost exclusively carboxylic or pyruvic acid.An effective new reagent, ceric ammonium nitrate in aqueous acetonitrile, was discovered for oxidative bisdecarboxylation of α-hydroxymalonic acids.Fortunately this reagent provides good to excellent yields of allylcarboxylic acids in many cases for which sodium periodate proved unsatisfactory.
Selectivity and Catalysis in Ene Reactions of Diethyl Oxomalonate
Salomon, Mary F.,Pardo, Simon N.,Salomon, Robert G.
, p. 2446 - 2454 (2007/10/02)
Stereoselectivity, regioselectivity, and structural selectivity of the thermal ene reactions of diethyl oxomalonate are strongly determined by steric approach control.For a series of 1-arylcyclopentenes thermal ene reactions only show a small enhancement of rate by electron-donating substituents (ρ = -1.2 +/- 0.2).Lewis acid catalysis is described which allows ene reactions of diethyl oxomalonate under thermally mild conditions.Furthermore, catalysis by SnCl4 profoundly modifies the selectivity of the ene reactions which show a strong enhancement of rate by electron-donating substituents (ρ = -3.9 +/- 0.3) for a series of 1-arylcyclopentenes.Structural selectivity can be dramatically reversed by catalysts since the influence of electronic factors is amplified by Lewis acids, and steric approach control becomes less important.
