1: 2,2,2-trimethylacetic acid With tetra(n-butyl)ammonium hydrogensulfate; sodium hydrogencarbonate in dichloromethane; water 0.5 h; Cooling with ice; 2: S-ethyl O-(1-iodoethyl) thiocarbonate in dichloromethane; water T=20°C; 144 h;

1.1: sodium iodide; 18-crown-6 ether / toluene / 4 h / 100 °C 2.1: tetra(n-butyl)ammonium hydrogensulfate; sodium hydrogencarbonate / water; dichloromethane / 0.5 h / |Cooling with ice 2.2: 144 h / 20 °C View Scheme