1.1: potassium tert-butylate / dimethyl sulfoxide / 0 - 20 °C / |Inert atmosphere 1.2: 4 h / 60 °C / |Inert atmosphere 2.1: dihydrogen peroxide / water; dichloromethane / 1.08 h / 20 °C / |Inert atmosphere; |Cooling with ice 3.1: tin(IV) chloride / dichloromethane / 12 h / -65 °C / |Inert atmosphere 4.1: diisobutylaluminium hydride / toluene / -78 - 0 °C / |Inert atmosphere View Scheme