1: H2 / Pd-C / ethanol / Ambient temperature 2: DMSO, (COCl)2, Et3N 3: NaH / dimethylformamide; tetrahydrofuran / 0 °C 4: H2 / Pd-C / ethyl acetate / Ambient temperature 5: tetrahydrofuran / -78 °C 6: 1.) O3, 2.) NaBH4 / 1.) CH2Cl2, -78 deg C 7: Et3N / 0 °C 8: 1N-HCl / tetrahydrofuran / Ambient temperature 9: K2CO3 / methanol 10: NaH / tetrahydrofuran / Ambient temperature 11: camphorsulfonic acid / CH2Cl2 / 0 °C 12: DMSO, (COCl)2, Et3N / CH2Cl2 13: 28 percent / (Ph3P)3RhCl / acetonitrile / 160 °C 14: DDQ / CH2Cl2; H2O 15: DMSO, (COCl)2 / CH2Cl2 16: TsOH / benzene 17: H2 / Pd-C / ethyl acetate 18: CrO3, H2SO4 / acetone 19: 2N-HCl / tetrahydrofuran / Ambient temperature 20: (C6H11)2NMgBr / methanol / -55 °C 21: DDQ / CH2Cl2 / 1.5 h / Ambient temperature; buffer (pH 6.86) View Scheme