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