hydrogenchloride T=0 - 5°C;

1: 78 percent / NEt3, Pd(OAc)2, tri-o-tolylphosphine / dimethylformamide / 24 h / Heating 2: 65 percent / NaBH4, 9 N HCl / tetrahydrofuran; aq. ethanol / 1.) pH 7, -35 deg C, 1 h, 2.) -20 deg C, overnight 3: 81 percent / 4.5 N HCl / 2.5 h / 100 °C 4: 100 percent / HCl gas / 0 - 5 °C View Scheme

1: 65 percent / NaBH4, 9 N HCl / tetrahydrofuran; aq. ethanol / 1.) pH 7, -35 deg C, 1 h, 2.) -20 deg C, overnight 2: 81 percent / 4.5 N HCl / 2.5 h / 100 °C 3: 100 percent / HCl gas / 0 - 5 °C View Scheme

1: 81 percent / 4.5 N HCl / 2.5 h / 100 °C 2: 100 percent / HCl gas / 0 - 5 °C View Scheme

1: 84 percent / triethylamine, DCC / tetrahydrofuran / Ambient temperature 2: 67 percent / trifluoroacetic acid / CH2Cl2 / 0.67 h / 0 °C 3: 75 percent / DCC / CH2Cl2 / 1.) -20 deg C to 0 deg C, 3 h, 2.) 4 deg C, 36 h 4: ethanethiol, AlBr3 / CH2Cl2 / 24 h / Ambient temperature 5: DCC, DMAP, DMAP-TFA / CHCl3 / 16 h / Heating View Scheme