1: 1.) SO2Cl2, 2.) NaN3 2: 75 percent / m-Chloroperoxybenzoic acid, NaHCO3 / CH2Cl2; H2O / 1 h / 0 - 10 °C 3: 84.5 percent / Potassium tert-butoxide / tetrahydrofuran / 0.25 h View Scheme