1: methanephosphonic acid dimethyl ester With n-butyllithium in tetrahydrofuran T=-78°C; 0.5 h; Inert atmosphere; 2: methyl 2-(4-fluorophenoxy)acetate in tetrahydrofuran T=-78 - 20°C; 2.5 h; Inert atmosphere;

1.1: sodium hydride / N,N-dimethyl-formamide / 90 °C / Inert atmosphere 2.1: n-butyllithium / tetrahydrofuran / 0.5 h / -78 °C / Inert atmosphere 2.2: 2.5 h / -78 - 20 °C / Inert atmosphere View Scheme