1: diethoxyphosphoryl-acetic acid ethyl ester With sodium hydride in tetrahydrofuran Horner-Wadsworth-Emmons olefination; 0.5 h; Inert atmosphere; 2: 2-trans,4-trans-n-heptadienal in tetrahydrofuran T=-35°C; Horner-Wadsworth-Emmons olefination; 1 h;