1: NaH / dimethylformamide; tetrahydrofuran / 0 °C 2: H2 / Pd-C / ethyl acetate / Ambient temperature 3: tetrahydrofuran / -78 °C 4: 1.) O3, 2.) NaBH4 / 1.) CH2Cl2, -78 deg C 5: Et3N / 0 °C 6: 1N-HCl / tetrahydrofuran / Ambient temperature 7: K2CO3 / methanol 8: NaH / tetrahydrofuran / Ambient temperature 9: camphorsulfonic acid / CH2Cl2 / 0 °C 10: DMSO, (COCl)2, Et3N / CH2Cl2 11: 28 percent / (Ph3P)3RhCl / acetonitrile / 160 °C 12: DDQ / CH2Cl2; H2O 13: DMSO, (COCl)2 / CH2Cl2 14: TsOH / benzene 15: H2 / Pd-C / ethyl acetate 16: CrO3, H2SO4 / acetone 17: 2N-HCl / tetrahydrofuran / Ambient temperature 18: (C6H11)2NMgBr / methanol / -55 °C 19: DDQ / CH2Cl2 / 1.5 h / Ambient temperature; buffer (pH 6.86) View Scheme