pyridine; triethylamine in dichloromethane from -30 to 20 deg C;

methanesulfonyl chloride; triethylamine in dichloromethane -20 deg C to r.t.; Yield given;

1: methanesulfonyl chloride, triethylamine / CH2Cl2 / -20 deg C to r.t. 2: 1) lithiumdiisopropylamide, hexamethylphosphoramide 2) CH3OH / 1a) -78 deg C -> -20 deg C, 3 h 1b) -20 deg C, 1 h 2) -78 deg C, 15 min 3: red HgO, BF3*OEt2 / tetrahydrofuran; H2O / 3 h / 20 °C View Scheme