trifluoroacetic anhydride T=25°C; 0.25 h;

1.1: DIBAL-H / CH2Cl2 / 0.5 h / -78 °C 1.2: aq. HCl; NH4Cl / ethyl acetate; CH2Cl2 / 0.33 h / 20 °C 2.1: 2.9 g / Jones reagent / acetone / -20 °C 3.1: 95 percent / aq. (TFA)2O / 0.25 h / 25 °C View Scheme

1: 2.9 g / Jones reagent / acetone / -20 °C 2: 95 percent / aq. (TFA)2O / 0.25 h / 25 °C View Scheme

1: 96 percent / dimethylformamide / 24 h / Ambient temperature 2: 1.) n-BuLi / 1.) THF, hexane, 5 min, -75 deg C; -75 deg C to -45 deg C, 15 min, 2.) -95 deg C, 4 h; -95 deg C to -65 deg C, 1 h 3: 95 percent / Na-Hg / methanol / 4.25 h / 0 °C 4: 88 percent / trifluoroacetic anhydride / 0.25 h View Scheme

1: 100 percent / PBr3 / diethyl ether / 0.17 h / 0 °C 2: 96 percent / dimethylformamide / 24 h / Ambient temperature 3: 1.) n-BuLi / 1.) THF, hexane, 5 min, -75 deg C; -75 deg C to -45 deg C, 15 min, 2.) -95 deg C, 4 h; -95 deg C to -65 deg C, 1 h 4: 95 percent / Na-Hg / methanol / 4.25 h / 0 °C 5: 88 percent / trifluoroacetic anhydride / 0.25 h View Scheme

1: 1.) n-BuLi / 1.) THF, hexane, 5 min, -75 deg C; -75 deg C to -45 deg C, 15 min, 2.) -95 deg C, 4 h; -95 deg C to -65 deg C, 1 h 2: 95 percent / Na-Hg / methanol / 4.25 h / 0 °C 3: 88 percent / trifluoroacetic anhydride / 0.25 h View Scheme

1: 95 percent / Na-Hg / methanol / 4.25 h / 0 °C 2: 88 percent / trifluoroacetic anhydride / 0.25 h View Scheme