trifluoroacetic acid in water T=-20°C; 5 h;

boron trifluoride diethyl etherate in acetonitrile

trifluoroacetic acid in water Ambient temperature;

1: pyridinium chlorochromate, 3 A mol. sieve / CH2Cl2 / 2 h 2: NaBH4 / propan-2-ol / 2 h / 0 °C 3: O3 / CH2Cl2 / -78 °C 4: imidazol / dimethylformamide / Ambient temperature 5: 62 percent / 1.62 M BuLi / hexane; tetrahydrofuran / 1.) 30 min; 2.) 3 h, -78 deg C 6: 1.) 1.9 M Me3Al / 1.) hexane, CH2Cl2, 20 min; 1 h; 2.) hexane, THF, CH2Cl2, -50 deg C 7: 91 percent / 90 percent m-chloroperbenzoic acid / CH2Cl2 / 1 h 8: 85 percent / DCC / 4-(dimethylamino)pyridine / CH2Cl2 / 24 h 9: 100 percent / 50 percent aq. CF3COOH / 2 h / Ambient temperature View Scheme

1: O3 / CH2Cl2 / -78 °C 2: imidazol / dimethylformamide / Ambient temperature 3: 62 percent / 1.62 M BuLi / hexane; tetrahydrofuran / 1.) 30 min; 2.) 3 h, -78 deg C 4: 1.) 1.9 M Me3Al / 1.) hexane, CH2Cl2, 20 min; 1 h; 2.) hexane, THF, CH2Cl2, -50 deg C 5: 91 percent / 90 percent m-chloroperbenzoic acid / CH2Cl2 / 1 h 6: 85 percent / DCC / 4-(dimethylamino)pyridine / CH2Cl2 / 24 h 7: 100 percent / 50 percent aq. CF3COOH / 2 h / Ambient temperature View Scheme

1: 1.) 1.9 M Me3Al / 1.) hexane, CH2Cl2, 20 min; 1 h; 2.) hexane, THF, CH2Cl2, -50 deg C 2: 91 percent / 90 percent m-chloroperbenzoic acid / CH2Cl2 / 1 h 3: 85 percent / DCC / 4-(dimethylamino)pyridine / CH2Cl2 / 24 h 4: 100 percent / 50 percent aq. CF3COOH / 2 h / Ambient temperature View Scheme

1: 85 percent / DCC / 4-(dimethylamino)pyridine / CH2Cl2 / 24 h 2: 100 percent / 50 percent aq. CF3COOH / 2 h / Ambient temperature View Scheme

trifluoroacetic acid 2 h; Ambient temperature;

1: 65 percent / pyridine / CH2Cl2 / 20 °C 2: cesium acetate / dimethylformamide 3: NBS*H2O 4: 65 percent / DIBAL-H / benzene; toluene 5: 87 percent / LiN(TMS)2 / tetrahydrofuran / -78 °C 6: 93 percent / BF3*OEt2 / dimethylsulfoxide 7: 71 percent / CH3SO3H / dimethylsulfoxide / 1.5 h / 20 °C 8: 54 percent / DCC; DMAP / tetrahydrofuran 9: 73 percent / TFA; water View Scheme

trifluoroacetic acid T=-20°C;