1.1: 83 percent / citric acid monohydrate / toluene / 6 h / Heating 2.1: 67 percent / Pd(OAc)2; triphenylphosphine; K2CO3 / dimethylformamide / 16 h / 110 °C 3.1: 87 percent / H2 / Pd/C / ethanol / 15 h / 20 °C 4.1: lithium; NH3 / tetrahydrofuran / 0.08 h / -78 °C 4.2: NH4Cl / tetrahydrofuran / -78 - 20 °C View Scheme

1.1: 83 percent / citric acid monohydrate / toluene / 6 h / Heating 2.1: 67 percent / Pd(OAc)2; triphenylphosphine; K2CO3 / dimethylformamide / 16 h / 110 °C 3.1: 87 percent / H2 / Pd/C / ethanol / 15 h / 20 °C 4.1: lithium; NH3 / tetrahydrofuran / 3 h / -78 °C 4.2: 88 percent / NH4Cl View Scheme

diisobutylaluminium hydride in hexane; dichloromethane T=-78 - -40°C; 1 h;

1: 74 percent / n-butyllithium / tetrahydrofuran; hexane / 1 h / 0 °C 2: 83 percent / i-Bu2AlH / CH2Cl2; hexane / 1 h / -78 - -40 °C View Scheme

citric acid in toluene 6 h; Heating;

1.1: 83 percent / citric acid monohydrate / toluene / 6 h / Heating 2.1: 67 percent / Pd(OAc)2; triphenylphosphine; K2CO3 / dimethylformamide / 16 h / 110 °C 3.1: 87 percent / H2 / Pd/C / ethanol / 15 h / 20 °C 4.1: lithium; NH3 / tetrahydrofuran / 3 h / -78 °C 4.2: 88 percent / NH4Cl 5.1: 82 percent / triethylamine / CH2Cl2 / 15 h / 20 °C View Scheme