1: 1) N-chlorosuccinimide, Me2S, 2) NEt3 / 1) toluene, -25 deg C, 5.5 h, 2) 20 min. 2: 91 percent / tetrahydrofuran / 1 h / -40 deg C to r.t. 3: 1) N-chlorosuccinimide, Me2S, 2) NEt3 / 1) toluene, -25 deg C, 5.5 h 2) 20 min 4: HBr, H2O / diethyl ether / 0.5 h / 0 °C 5: NaHCO3, Na2CO3 / H2O / 2.5 h / Ambient temperature 6: 80 percent / pyridine / 20 h / 0 °C 7: pyridine / CH2Cl2 / 0.33 h / -15 °C 8: 1) Bu4NOAc, 2) DMAP, Py / 1) CH3CN, 40 deg C, 50 min, 2) 3 h, r.t. 9: 93 percent / NaBH4 / ethanol 10: 93 percent / K2CO3 / methanol / 1 h / 0 °C 11: 1) methyl triflate, 2) N-methylimidazole / 1) THF, 0 deg C, 40 min, 2) THF 12: 89 percent / H2, NaOAc / 10percent Pd/C / methanol 13: 95 percent / CF3COOH / H2O; dioxane View Scheme