Electrochemical Oxidation of (S)-Malic-Acid Derivatives: a Route to Enantiomerically Pure Alkylmalonaldehydic Esters

Article abstract of DOI:10.1002/hlca.19870700204

The 3,3-dialkylmalic-acid diesters, prepared by the previously described diastereoselective alkylations through dilithium alkoxide enolates, are saponified to the monoesters containing a free α-hydroxycarboxylic-acid moiety.The monoesters are subjected to electrochemical oxidative decarboxylation in MeOH.If the intermediate monoacids are purified, the malonaldehydic esters (2-formyl-2-alkoxycarboxylates) obtained by this procedure are enantiomerically pure; they have the same structural features, i.e. two enantiotopic functionalized branches on the (persubstituted) stereogenic center, as the well known 3-hydroxy-2-methylpropanoic acid ('Roche acid') which was employed frequently as a starting material for the preparation of either enantiomer of various target molecules.