1: 4-(diethoxyphosphoryl)-3-oxo-butyric acid ethyl ester With n-butyllithium in tetrahydrofuran; hexane T=0 - 20°C; 2: 4-nitrobenzaldehdye in tetrahydrofuran; hexane T=20°C; 2.5 h;

water; sodium hydride in tetrahydrofuran T=35 - 40°C; 1 h;

in tetrahydrofuran Ambient temperature;