triethylamine in dichloromethane T=0°C; 0.25 h;

1: 57 percent / imidazole / dimethylformamide 2: 62 percent / pyridinium chlorochromate, NaOAc / CH2Cl2 3: n-BuLi / tetrahydrofuran; hexane / 1.) -85 deg C, 15 min, 2.) -85 deg C to 0 deg C, 2 h 4: 3 N aq. NaOH / methanol / 1.5 h 5: 92 percent / Et3N / CH2Cl2 / 0.25 h / 0 °C View Scheme

1: 62 percent / pyridinium chlorochromate, NaOAc / CH2Cl2 2: n-BuLi / tetrahydrofuran; hexane / 1.) -85 deg C, 15 min, 2.) -85 deg C to 0 deg C, 2 h 3: 3 N aq. NaOH / methanol / 1.5 h 4: 92 percent / Et3N / CH2Cl2 / 0.25 h / 0 °C View Scheme

1: n-BuLi / tetrahydrofuran; hexane / 1.) -85 deg C, 15 min, 2.) -85 deg C to 0 deg C, 2 h 2: 3 N aq. NaOH / methanol / 1.5 h 3: 92 percent / Et3N / CH2Cl2 / 0.25 h / 0 °C View Scheme

1: 57 percent / imidazole / dimethylformamide 2: 62 percent / pyridinium chlorochromate, NaOAc / CH2Cl2 3: n-BuLi / tetrahydrofuran; hexane / 1.) -85 deg C, 15 min, 2.) -85 deg C to 0 deg C, 2 h 4: 3 N aq. NaOH / methanol / 1.5 h 5: 92 percent / Et3N / CH2Cl2 / 0.25 h / 0 °C View Scheme

1: 3 N aq. NaOH / methanol / 1.5 h 2: 92 percent / Et3N / CH2Cl2 / 0.25 h / 0 °C View Scheme