1.1: tetrabutylammomium bromide; dihydrogen peroxide / dichloromethane; water / 10 - 20 °C 1.2: 0.5 h / 20 °C 2.1: dichloromethane; water / 2 h / 20 °C 2.2: 0.5 h / Reflux 3.1: sodium t-butanolate / tetrahydrofuran / -20 - -15 °C View Scheme