trifluoroacetic acid in chloroform T=20°C; 9 h;

1.1: NaH / tetrahydrofuran / 0.5 h / 0 °C 1.2: 100 percent / tetrahydrofuran / 4 h / 20 °C 2.1: 100 percent / LiAlH4 / diethyl ether / 17 h / 20 °C 3.1: NaH / tetrahydrofuran; dimethylformamide / 0.25 h / 0 °C 3.2: 58 percent / tetrahydrofuran; dimethylformamide / 36 h / 20 °C 4.1: 68 percent / aq. trifluoroacetic acid / CHCl3 / 9 h / 20 °C View Scheme

1.1: NaH / tetrahydrofuran; dimethylformamide / 0.25 h / 0 °C 1.2: 58 percent / tetrahydrofuran; dimethylformamide / 36 h / 20 °C 2.1: 68 percent / aq. trifluoroacetic acid / CHCl3 / 9 h / 20 °C View Scheme

1.1: NaH / tetrahydrofuran; dimethylformamide / 0.25 h / 0 °C 1.2: 58 percent / tetrahydrofuran; dimethylformamide / 36 h / 20 °C 2.1: 68 percent / aq. trifluoroacetic acid / CHCl3 / 9 h / 20 °C View Scheme

1.1: 100 percent / LiAlH4 / diethyl ether / 17 h / 20 °C 2.1: NaH / tetrahydrofuran; dimethylformamide / 0.25 h / 0 °C 2.2: 58 percent / tetrahydrofuran; dimethylformamide / 36 h / 20 °C 3.1: 68 percent / aq. trifluoroacetic acid / CHCl3 / 9 h / 20 °C View Scheme