tetrafluoroboric acid; trifluoroacetic acid in diethyl ether; dichloromethane T=20°C; 4 h;

in tetrahydrofuran 0.666667 h; Ambient temperature;

ammonium cerium (IV) nitrate; sodium hydrogencarbonate in acetonitrile T=80°C; 0.5 h;

1: sodium hydrosulfide monohydrate / ethanol / 20 °C 2: ammonium cerium (IV) nitrate; sodium hydrogencarbonate / acetonitrile / 0.5 h / 80 °C View Scheme

n-butyllithium 1.) ether, hexane, -78 deg C, 2 h, 2.) ether, hexane, -78 deg C to r.t.; Yield givenMultistep reaction;

1: 1.) n-BuLi / 1.) ether, hexane, -78 deg C, 2 h, 2.) ether, hexane, -78 deg C to r.t. 2: 70 percent / HOBt, DCC, DIEA / tetrahydrofuran / 48 h / -5 °C 3: 61 percent / NaOH, H2O / methanol / 4 h / 23 °C View Scheme

1: 82 percent / triphenylphosphine; copper(II) iodide; triethylamine / bis(triphenylphosphine)palladium(II) chloride / 1 h / Heating 2: 86 percent / potassium hydroxide / propan-2-ol / 3 h / Heating View Scheme

1: 1.) n-BuLi / 1.) ether, hexane, -78 deg C, 2 h, 2.) ether, hexane, -78 deg C to r.t. 2: 62 percent / NaOH, H2O / 4 h / Ambient temperature 3: 2.) Me2NH*BH3 / 1.) glacial acetic acid, r.t., 15 min, 2.) glacial acetic acid, r.t., 20 min; 60 deg C, 10 min 4: 75 percent / trifluoroacetic acid / 1.5 h / Heating 5: NEt3 / dimethylformamide / 0.25 h / 5 °C 6: dimethylformamide / 72 h / Ambient temperature 7: 10 percent / NaOH, H2O / 1.5 h / Heating View Scheme

1: 1.) n-BuLi / 1.) ether, hexane, -78 deg C, 2 h, 2.) ether, hexane, -78 deg C to r.t. 2: 62 percent / NaOH, H2O / 4 h / Ambient temperature View Scheme