1: 1a.) CuI, 1b.) HMPA / 1a.) THF, 0 deg C, 20 min, 1b.) -78 deg C, 15 min, 2.) -78 deg C 2: 100 percent / MCPBA / CH2Cl2 / 1 h / Ambient temperature 3: 91 percent / 5percent sodium amalgam / ethanol / 12 h / Heating 4: BF3*CH3COOH / CH2Cl2 / 2 h / Ambient temperature 5: MCPBA, KF / dimethylformamide / 40 h / Ambient temperature View Scheme

Multi-step reaction with 2 steps 1: 1a.) CuI, 1b.) HMPA / 1a.) THF, 0 deg C, 20 min, 1b.) -78 deg C, 15 min, 2.) -78 deg C2: 100 percent / MCPBA / CH2Cl2 / 1 h / Ambient temperature