Water → (S)-(+)-2-Methylbutyl p-toluenesulfonate

To a ice-cooled solution of p-toluenesulphonyl chloride (9.53 g, 50 mmol), (S)-2-methylbutan-1-ol (4.41 g, 50 mmol) in absolute dichloromethane (200 ml), triethylamine (84 ml) was dropwise added. After complete addition and stirring for further 6 h at room temperature, the reaction mixture was poured into water (150 ml), the organic layer was separated and the aqueous phase was further extracted with dichloromethane (2×200 ml). The combined organic extracts were washed with HCl 1N (2×200 ml), with saturated NaCl solution (2×200 ml), dried over magnesium sulphate and evaporated under reduced pressure. The obtained slightly yellow oil was chromatographed on silica (diethylether/petroleumether: 1/3) to give (s)-2-methyl-butyl p-toluenesulphonate as a colourless oil (Yield: 10.0 g, 89%).