1: 90 percent / CF3COOH / H2O; tetrahydrofuran / 5 h 2: 83 percent / NaBH(OAc)3 / toluene / 0.75 h / 80 °C 3: 90 percent / pyridine / CH2Cl2 / 18 h / 4 °C 4: 73 percent / Na2S / dimethylformamide / 3 h / 100 °C 5: 82 percent / diethyl azodicarboxylate, PPh3 / tetrahydrofuran / 0.83 h / Ambient temperature 6: 81 percent / K2CO3 / methanol / 0.5 h 7: 94 percent / DMAP / CH2Cl2 / 1 h / 0 °C 8: 26 percent / K2CO3 / dimethylsulfoxide / 85 °C 9: 1) BBr3, 2) aq. NH3 / 1) CH2Cl2, 2) CH2Cl2, 45 min View Scheme