1: methanephosphonic acid dimethyl ester With n-butyllithium in tetrahydrofuran T=-78°C; 1 h; 2: 3-[1,3]Dioxolan-2-yl-propionic acid methyl ester in tetrahydrofuran T=-78°C; 3 h;

trifluorormethanesulfonic acid in nitromethane 0.5 h; Ambient temperature;

n-butyllithium 1) THF, hexane, -78 deg C, 1h, 2) -78 deg C, 3h; Yield given. Multistep reaction;

1.1: iodine; magnesium; 1,2-dibromoethane / tetrahydrofuran / 1 h 1.2: 65 percent / tetrahydrofuran / -78 - 20 °C 2.1: n-BuLi / tetrahydrofuran / 1 h / -78 °C 2.2: 65 percent / tetrahydrofuran / 3 h / -78 °C View Scheme