1.1: dimethylsulfide borane complex / tetrahydrofuran / 0 - 20 °C 1.2: 0 °C 2.1: triethylamine; methanesulfonyl chloride / dichloromethane / 0 °C View Scheme

1: With dimethylsulfide borane complex in tetrahydrofuran T=0 - 20°C; 2: With dihydrogen peroxide; sodium hydroxide in tetrahydrofuran; water T=0°C;