1: 81 percent / KOtBu / tetrahydrofuran / 0.17 h / 0 °C 2: 86 percent / 10percent aq. HCl / methanol / 0.25 h / Ambient temperature 3: 1.) NaH / 1.) THF, DMF, RT, 30 min, 2.) RT, 2h 4: 42 percent / 10percent aq. HCl / methanol / 0.67 h / 70 °C 5: 1.) DMSO, oxalyl chloride, 2.) NEt3 / 1.) CH2Cl2, -20 deg C, 20 min, 2.) -20 deg C, 5 min 6: 63 percent / tetrahydrofuran / 1 h / -78 °C 7: 1.) NaH / 1.) THF, DMF, RT, 2.) RT 8: 1.) borane-THF complex, 2.) 30percent H2O2, 3N NaOH / 1.) THF, 45 deg C, 1h, 2.) 60 deg C, 1h 9: 1.) NEt3, 2.) H2, HCl / 2.) 10percent Pd/C / 1.) CH2Cl2, RT, 16h, 2.) EtOH, MeOH, 1 atm, RT, 6h View Scheme