in toluene T=80°C; 1 h;

1: diethyl methoxycarbonylmethyl-phosphonate With sodium hydride in tetrahydrofuran T=0°C; 1 h; Inert atmosphere; 2: 5-bromo-2-furancarboxaldehyde in tetrahydrofuran T=0 - 20°C; Horner-Wadsworth-Emmons reaction; 0.5 h; Inert atmosphere;