1: With bis-[(trifluoroacetoxy)iodo]benzene in tetrahydrofuran; methanol T=20°C; 0.25 h; 2: With toluene-4-sulfonic acid in trans-1,3-dioxane; water T=50°C; 3 h; enantioselective reaction;

1: 80 percent / 5percent aq. NaOH / 1 h / Ambient temperature 2: Et3N / CH2Cl2 / 1 h / Ambient temperature 3: DBU / toluene / 1 h / 100 °C 4: 1.) O3, 2.) Me2S / 1.) MeOH, -78 deg C, 2.) -78 deg C to room temp. View Scheme

sulfur trioxide pyridine complex in dimethyl sulfoxide 0.5 h; 0 deg C to room temp.;

1: 80 percent / LiEt3BH / tetrahydrofuran / 2 h / -78 °C 2: 80 percent / pyridinium p-toluenesulfonate / 3 h / Ambient temperature 3: BF3*Et2O / CH2Cl2 / 1 h / Ambient temperature 4: 64 percent / BF3*THF / tetrahydrofuran / 1.) room temp., 15 min, 2.) reflux, 24 h 5: 80 percent / 5percent aq. NaOH / 1 h / Ambient temperature 6: Et3N / CH2Cl2 / 1 h / Ambient temperature 7: DBU / toluene / 1 h / 100 °C 8: 1.) O3, 2.) Me2S / 1.) MeOH, -78 deg C, 2.) -78 deg C to room temp. View Scheme

1: Et3N / CH2Cl2 / 1 h / Ambient temperature 2: DBU / toluene / 1 h / 100 °C 3: 1.) O3, 2.) Me2S / 1.) MeOH, -78 deg C, 2.) -78 deg C to room temp. View Scheme

1: DBU / toluene / 1 h / 100 °C 2: 1.) O3, 2.) Me2S / 1.) MeOH, -78 deg C, 2.) -78 deg C to room temp. View Scheme

1: 64 percent / BF3*THF / tetrahydrofuran / 1.) room temp., 15 min, 2.) reflux, 24 h 2: 80 percent / 5percent aq. NaOH / 1 h / Ambient temperature 3: Et3N / CH2Cl2 / 1 h / Ambient temperature 4: DBU / toluene / 1 h / 100 °C 5: 1.) O3, 2.) Me2S / 1.) MeOH, -78 deg C, 2.) -78 deg C to room temp. View Scheme

1: BH3.SMe2 / tetrahydrofuran / 10 h / 0 deg C to room temp. 2: pyridine.SO3 / dimethylsulfoxide / 0.5 h / 0 deg C to room temp. View Scheme

1: 4N NaOH / 6 h / Ambient temperature 2: BH3.SMe2 / tetrahydrofuran / 10 h / 0 deg C to room temp. 3: pyridine.SO3 / dimethylsulfoxide / 0.5 h / 0 deg C to room temp. View Scheme

dimethylsulfide; ozone 1.) MeOH, -78 deg C, 2.) -78 deg C to room temp.; Multistep reaction;