1: 2N-HCl / tetrahydrofuran / Ambient temperature 2: (C6H11)2NMgBr / methanol / -55 °C 3: DDQ / CH2Cl2 / 1.5 h / Ambient temperature; buffer (pH 6.86) View Scheme

Multi-step reaction with 4 steps 1: 1) DMSO, (COCl)2, 2) Et3N / 1) CH2Cl2, -70 deg C, 2) CH2Cl2, -70 to 0 deg C2: 100 percent / p-TsOH / benzene / 1.5 h / Heating; Dean-Stark apparatus3: 83 percent / hydrogen / 10percent Pd/C / ethyl acetate / 15 h / Ambient temperature4: 82 percent / CrO3, H2SO4 / acetone / 0.67 h / 0 °C  

Multi-step reaction with 14 steps 1: 97 percent / tetrahydrofuran / 3 h / -40 °C2: 1) O3, 2) NaBH4 / 1) CH2Cl2, -78 deg C, 20 min, 2) CH2Cl2, MeOH, -78 deg C, 15 min3: 94 percent / Et3N / toluene / 2 h / 0 °C4: 1N HCl / tetrahydrofuran / 4 h / Ambient temperature5: K2CO3 / methanol; H2O / 1 h6: 91 percent / NaH / dimethylsulfoxide / 1 h / Ambient temperature7: 83 percent / CSA / CH2Cl2 / 0.33 h / 0 °C8: 1) (COCl)2, DMSO, 2) Et3N / 1) CH2Cl2, -70 deg C, 2) CH2Cl2, -70 to 0 deg C9: 28 percent / (Ph3P)3RhCl / acetonitrile / 9 h / 160 °C / sealed tube10: 100 percent / DDQ / CH2Cl2; H2O11: 1) DMSO, (COCl)2, 2) Et3N / 1) CH2Cl2, -70 deg C, 2) CH2Cl2, -70 to 0 deg C12: 100 percent / p-TsOH / benzene / 1.5 h / Heating; Dean-Stark apparatus13: 83 percent / hydrogen / 10percent Pd/C / ethyl acetate / 15 h / Ambient temperature14: 82 percent / CrO3, H2SO4 / acetone / 0.67 h / 0 °C  

With  hydrogenchloride in  tetrahydrofuran 4 h;  Ambient temperature;