potassium tert-butylate in tetrahydrofuran T=-78°C; 3 h;

1: 67 percent / Na2S / aq. ethanol / 4 h / 20 °C 2: 65 percent / Oxone / CH2Cl2 / 50 °C 3: 65 percent / KOH-Al2O3; CBr2F2 / CH2Cl2 View Scheme

1: 66 percent / CBr4; Ph3P / benzene / 3 h 2: 67 percent / Na2S / aq. ethanol / 4 h / 20 °C 3: 65 percent / Oxone / CH2Cl2 / 50 °C 4: 65 percent / KOH-Al2O3; CBr2F2 / CH2Cl2 View Scheme

1: 65 percent / Oxone / CH2Cl2 / 50 °C 2: 65 percent / KOH-Al2O3; CBr2F2 / CH2Cl2 View Scheme

1: pyridinium toluene-p-sulfonate / methanol / 24 h 2: 66 percent / CBr4; Ph3P / benzene / 3 h 3: 67 percent / Na2S / aq. ethanol / 4 h / 20 °C 4: 65 percent / Oxone / CH2Cl2 / 50 °C 5: 65 percent / KOH-Al2O3; CBr2F2 / CH2Cl2 View Scheme

1: 1.) n-BuLi, 2.) HMPA / 1.) THF, hexane, -78 deg C, 10 min, 2.) THF, hexane, a) from -78 deg C to RT, 2 h, b) RT, 16 h 2: pyridinium p-toluenesulfonate / methanol / 18 h 3: 92 percent / CBr4, n-Bu3P / diethyl ether / 0.25 h / 0 °C 4: 31 percent / Na2S*9H2O / ethanol; H2O / 25 °C 5: 68 percent / m-chloroperbenzoic acid / CH2Cl2 / 0.5 h / -30 °C 6: pyridine, SO2Cl2 / CH2Cl2 / 0.67 h / -78 °C 7: m-chloroperbenzoic acid / CH2Cl2 / 16 h / Ambient temperature 8: 32 percent / t-BuOK / tetrahydrofuran / 3 h / -78 °C View Scheme

aluminum oxide; potassium hydroxide; dibromo-difluoro-methane in dichloromethane

1: 1) n-BuLi, 2) HMPA / 1) THF, -78 to 0 deg C, 25 min, 2) 0 to 23 deg C, 12 h 2: 95 percent / camphorsulfonic acid / methanol; H2O / 2 h / Heating 3: 94 percent / toluene / Heating; 5 to 15 min 4: 1,2,3-trimethyl-1,3-diaza-2-phospholidine / 50 h / -20 - -5 °C View Scheme

sodium carbonate T=50°C; 72 h; various conc. of TFE; other solvent: EtOH; also in addition of LiBr; other temp.; ΔH(excit.), half fife time; Product distributionThermodynamic dataKinetics;