1: NaBH4 / tetrahydrofuran; ethanol 2: imidazole / dimethylformamide 3: Br2 / CCl4 4: 67 percent / Li2CO3, LiBr / dimethylformamide 5: tetrahydrofuran 6: LiN(iPr)2 / tetrahydrofuran 7: LiCl, methanesulfonyl chloride / dimethylformamide 8: K2CO3, CuI, Bu4NBr / dimethylformamide 9: 90 percent / H2 / Lindlar catalyst 10: 83 percent / Bu4NF, H2O / tetrahydrofuran 11: Dess-Martin periodinane, NaOAc / CH2Cl2 12: TiCl3*DME1.5, Zn-Cu / 1,2-dimethoxy-ethane / 36 h / 0 °C 13: 1.) MsCl, pyridine 2.) Bu4NOH / 1.) ether; 2.) THF 14: LiN(iPr)2 / tetrahydrofuran 15: 84 percent / Dess-Martin periodinane View Scheme

Multi-step reaction with 11 steps 1: NaBH4 / tetrahydrofuran; ethanol2: imidazole / dimethylformamide3: Br2 / CCl4 4: 67 percent / Li2CO3, LiBr / dimethylformamide5: tetrahydrofuran6: LiN(iPr)2 / tetrahydrofuran7: LiCl, methanesulfonyl chloride / dimethylformamide8: K2CO3, CuI, Bu4NBr / dimethylformamide9: 90 percent / H2 / Lindlar catalyst10: 83 percent / Bu4NF, H2O / tetrahydrofuran11: Dess-Martin periodinane, NaOAc / CH2Cl2