1: 85 percent / p-TsOH / CH2Cl2 / 1.) RT, 2 h, 2.) reflux, 2.5 h 2: 70 percent / SmI2, HMPA, ethylene glycol / tetrahydrofuran / 3.5 h / Ambient temperature 3: 1.) DMSO, (CF3CO)2O, 2.) Et3N / 1.) CH2Cl2, -78 deg C, 15 min, 2.) CH2Cl2, -78 deg C, 30 min 4: 1.) NaH, HMPA / 1.) THF, 0 deg C, 1 h, 2.) THF, RT, 6.5 h 5: tetrabutylammonium fluoride / tetrahydrofuran / 2.5 h / 0 °C 6: 77 percent / PCC, AcONa, molecular sieves 3 Angstroem / CH2Cl2 / 1 h / Ambient temperature 7: 1.) n-BuLi / 1.) THF, -20 deg C, 15 min, 2.) THF, -20 deg C, 3 h 8: 1.) DMSO, (CF3CO)2O, 2.) Et3N / 1.) CH2Cl2, -78 deg C, 30 min, 2.) CH2Cl2, -78 deg C, 1 h 9: 88 percent / Ph3P / toluene / 8.5 h / Heating 10: 62 percent / 5percent HCl / methanol / 10 h / Ambient temperature View Scheme