The reaction of acetylenic amines 1 with electrochemically generated tetraethylammonium carbonate (TEAC) or chemically generated tetraethylammonium hydrogen carbonate (TEAHC) is reported. Unsubstituted or substituted 5-methylene-1,3-oxazolidin-2-ones 2 are obtained in moderate to very high yields according to the reaction conditions adopted and to the nature of the substrate.