boron trifluoride diethyl etherate in dichloromethane T=0 - 20°C; Substitution; 4 h;

tetra(n-butyl)ammonium hydrogensulfate; sodium carbonate in ethyl acetate T=20°C; Inert atmosphere;

1: NapSSNap With hydrogenchloride; triphenylphosphine in toluene T=70°C; 0.75 h; 2: 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl bromide With tetra(n-butyl)ammonium hydrogensulfate; sodium carbonate in water; toluene T=20°C; Further stages.;

boron trifluoride diethyl etherate T=20°C; 1 h; Ionic liquid;

1: carbon tetrabromide; triphenylphosphine / dichloromethane / 4 h / 20 °C 2: sodium carbonate; tetrabutylammomium bromide / dichloromethane; water / 6 h / 20 °C View Scheme