1: tetrahydrofuran-3-carbaldehyde With hydrogen; ammonium chloride; Raney nickel in methanol; water T=20°C; P=2068.65 Torr; 16 h; 2: di-tert-butyl dicarbonate With sodium hydroxide in 1,4-dioxane; water T=20°C; 16 h; 3: With hydrogenchloride in 1,4-dioxane

1: With hydrazine hydrate in ethanol T=70°C; 6 h; Inert atmosphere; 2: in ethanol T=60°C; 4 h;

1.1: pyridine / 4 h / Inert atmosphere; Cooling with ice 2.1: potassium iodide / N,N-dimethyl-formamide / 3 h / 80 °C / Inert atmosphere 3.1: hydrazine hydrate / ethanol / 6 h / 70 °C / Inert atmosphere 3.2: Raney nickel / 4 h / 60 °C View Scheme

1.1: potassium iodide / N,N-dimethyl-formamide / 3 h / 80 °C / Inert atmosphere 2.1: hydrazine hydrate / ethanol / 6 h / 70 °C / Inert atmosphere 2.2: Raney nickel / 4 h / 60 °C View Scheme