The Passerini reaction between arylglyoxals 1, isocyanides 2, and cyanoacetic acid affords N-substituted 3-aryl-2-cyanoacetoxy-3-oxopropionamides 3, which are cyclized in the presence of triethylamine to give N-substituted 3-aryl-4-cyano-2,5-dihydro-5-oxofuran-2-carboxamides 4