2: CSA / toluene 3: imidazole, DMAP / dimethylformamide 4: LiAlH4 / tetrahydrofuran / 0 °C 5: 1.) t-BuLi, 2.) O2 / 1.) THF, -78 deg C 6: PCC/Al2O3 7: i-Pr2NEt, DMAP / CH2Cl2 8: 1.) NaN(TMS)2 / 1.) THF, HMPA 9: pyridine*(HF)x / tetrahydrofuran 10: 83 percent / n-Bu4NF 11: 49 percent / 3 N HCl / tetrahydrofuran View Scheme