Methanesulfonyl chloride → 2-(Methylsulfonyl)ethyl methanesulfonate

In a 50 mL round-bottomed flask, 2-(methylsulfonyl)ethanol (1.24 g, 9.99 mmol, Eq: 1.00) was combined with DCM (5 mL). To the resulting solution was added diisopropylethylamine (2.1 mL, 12.0 mmol, Eq: 1.2) and methanesulfonyl chloride (1.37 g, 931 μL, 12.0 mmol, Eq: 1.2). The ice bath was removed and the reaction was stirred at rt overnight. The crude reaction mixture was concentrated in vacuo and the residue was partitioned between EtOAc and water. The organic layer was dried over Na2SO4 and concentrated in vacuo. The crude material was purified by flash chromatography (silica gel, 80 g, 10% to 80% EtOAc in hexanes) to give 2-(methylsulfonyl)ethyl methanesulfonate (1.01 g).