sodium tetrahydroborate in methanol T=20 - 25°C; 2 h; Yield given;

1: 95.5 percent / K2CO3, tetra-n-butylammonium chloride / acetonitrile / 22 h / Heating 2: 94.9 percent / N-methylpyrrolidone / 1.5 h / Heating 3: OsO4 / diethyl ether; H2O / 0.17 h / 20 - 25 °C 4: NaIO4 / diethyl ether; H2O / 12 h / 20 - 25 °C 5: NaBH4 / methanol / 2 h / 20 - 25 °C View Scheme

1: 94.9 percent / N-methylpyrrolidone / 1.5 h / Heating 2: OsO4 / diethyl ether; H2O / 0.17 h / 20 - 25 °C 3: NaIO4 / diethyl ether; H2O / 12 h / 20 - 25 °C 4: NaBH4 / methanol / 2 h / 20 - 25 °C View Scheme

1: OsO4 / diethyl ether; H2O / 0.17 h / 20 - 25 °C 2: NaIO4 / diethyl ether; H2O / 12 h / 20 - 25 °C 3: NaBH4 / methanol / 2 h / 20 - 25 °C View Scheme

triphenylphosphine; diethylazodicarboxylate in tetrahydrofuran T=20 - 25°C; 1 h;

1: 86.7 percent / diethyl azodicarboxylate, Ph3P / tetrahydrofuran / 1 h / 20 - 25 °C 2: NCS / dimethylformamide / 3 h / 70 °C View Scheme

1: 86.7 percent / diethyl azodicarboxylate, Ph3P / tetrahydrofuran / 1 h / 20 - 25 °C 2: NCS / dimethylformamide / 3 h / 70 °C 3: 90.3 percent / 4N NaOH / methanol / 2 h / Heating View Scheme