lithium bromide; lithium diisopropyl amide in tetrahydrofuran T=-78°C; 8 h;

1: 91 percent / TfOH / methanol / 6.5 h / 80 °C 2: 97 percent / imidazole / dimethylformamide / 3.5 h / 23 °C 3: 96 percent / TsOH / benzene / 0.5 h / Heating 4: LiBH4 / tetrahydrofuran; methanol / 24 h / 23 °C 5: DMSO, (COCl)2, Et3N / CH2Cl2 / 1.5 h / -78 °C 6: 1.) LDA / 1.) THF, -78 deg C 7: 87 percent / H2 / Pd/C / ethanol / 24 h / 23 °C View Scheme

1: trifluoromethanesulfonic acid / methanol; H2O / 6.5 h / 80 - 85 °C 2: imidazole / dimethylformamide / 25 h / 23 °C 3: p-TsOH*H2O / benzene / 0.5 h / 80 °C View Scheme

1: trifluoromethanesulfonic acid / methanol; H2O / 6.5 h / 80 - 85 °C 2: imidazole / dimethylformamide / 25 h / 23 °C 3: p-TsOH*H2O / benzene / 0.5 h / 80 °C 4: LiBH4 / tetrahydrofuran; methanol / 20 h / 23 °C View Scheme

trifluorormethanesulfonic acid in methanol T=80°C; 6.5 h;

1: 91 percent / TfOH / methanol / 6.5 h / 80 °C 2: 97 percent / imidazole / dimethylformamide / 3.5 h / 23 °C 3: 96 percent / TsOH / benzene / 0.5 h / Heating 4: LiBH4 / tetrahydrofuran; methanol / 24 h / 23 °C 5: DMSO, (COCl)2, Et3N / CH2Cl2 / 1.5 h / -78 °C 6: 1.) LDA / 1.) THF, -78 deg C 7: 87 percent / H2 / Pd/C / ethanol / 24 h / 23 °C 8: 90 percent / 5percent HF / acetonitrile / 9 h / 23 °C View Scheme

1: 91 percent / TfOH / methanol / 6.5 h / 80 °C 2: 97 percent / imidazole / dimethylformamide / 3.5 h / 23 °C 3: 96 percent / TsOH / benzene / 0.5 h / Heating 4: LiBH4 / tetrahydrofuran; methanol / 24 h / 23 °C 5: DMSO, (COCl)2, Et3N / CH2Cl2 / 1.5 h / -78 °C 6: 1.) LDA / 1.) THF, -78 deg C 7: 87 percent / H2 / Pd/C / ethanol / 24 h / 23 °C 8: 90 percent / 5percent HF / acetonitrile / 9 h / 23 °C 9: 73 percent / DMSO, (COCl)2, Et3N / CH2Cl2 / 2 h / -78 °C 10: 95 percent / NaClO2, NaH2PO4 / 2-methyl-propan-2-ol; various solvent(s) / 0.25 h / 23 °C 11: 95 percent / 1,3-propanedithiol, 2percent HCl (gas) / various solvent(s) / 6 h / 50 °C View Scheme