formaldehyd; sodium cyanoborohydride in water; acetonitrile T=0 - 20°C; 168 h;

sodium hydride in N,N-dimethyl-formamide T=0°C; Inert atmosphere;

sodium cyanoborohydride; acetic acid in water; acetonitrile T=20°C; 168 h;

1.1: Br2; aq. Na2CO3 / CH2Cl2 / 0.5 h / 0 °C 2.1: Mg; 1,2-dibromoethane / tetrahydrofuran / 0.5 h 2.2: 77 percent / tetrahydrofuran / 20 °C 3.1: KOtBu / 1,2-dimethoxy-ethane / 0.17 h / -50 °C 3.2: 80 percent / 1,2-dimethoxy-ethane / 0.5 h / -50 °C 4.1: 80 percent / NaH / tetrahydrofuran / 20 °C 5.1: 93 percent / hydrazine hydrobromide / ethanol; H2O / 1 h / Heating 6.1: 62 percent / dioxane / 20 h / Heating 7.1: 99 percent / POCl3 / acetonitrile / 8 h / Heating 8.1: 72 percent / acetonitrile / 3 h / Heating View Scheme

bromine; sodium carbonate in dichloromethane; water T=0°C; 1 h;

1.1: Br2; aq. Na2CO3 / CH2Cl2 / 0.5 h / 0 °C 2.1: Mg; 1,2-dibromoethane / tetrahydrofuran / 0.5 h 2.2: 77 percent / tetrahydrofuran / 20 °C View Scheme