1.1: O3 / CH2Cl2 / -78 °C 1.2: 73 percent / Et2NH / CH2Cl2 / -78 - 20 °C 2.1: NaClO2; NaH2PO4*2H2O; 2-methyl-2-butene / H2O; 2-methyl-propan-2-ol / 2.5 h / 20 °C 3.1: CH2Cl2; diethyl ether / 20 °C 4.1: 75 percent / AcCl / methanol / 7 h / 20 °C View Scheme