1.1: lithium aluminium tetrahydride / diethyl ether / 3 h / 0 - 20 °C / Inert atmosphere 1.2: 0.5 h / 0 °C 2.1: bromine; triphenylphosphine / chloroform / 3 h / 20 °C / Inert atmosphere 3.1: magnesium / tetrahydrofuran 3.2: 9 h / 2 - 20 °C / Inert atmosphere 4.1: methanol; toluene-4-sulfonic acid / 24 h / 20 °C 5.1: pyridine / 24 h / 20 °C View Scheme

1: 78 percent / LiAlH4 / diethyl ether / 0 deg C to 5 deg C, 1 h, rt, 2 h 2: 81 percent / PBr3, Py / diethyl ether / -15 deg C to -10 deg C, 2 h, rt, 2 d 3: 1.) CuI, 2,2'-bipyridyl, Mg, 2.) TsOH / 1.) THF, HF, 20 deg C, 2 h, 20 deg C, 16 h, reflux, 4 h, 2.) EtOH, rt, 24 h View Scheme

1.1: lithium aluminium tetrahydride / diethyl ether / 3 h / 0 - 20 °C / Inert atmosphere 1.2: 0.5 h / 0 °C 2.1: bromine; triphenylphosphine / chloroform / 3 h / 20 °C / Inert atmosphere 3.1: magnesium / tetrahydrofuran 3.2: 9 h / 2 - 20 °C / Inert atmosphere 4.1: methanol; toluene-4-sulfonic acid / 24 h / 20 °C View Scheme

1: 78 percent / LiAlH4 / diethyl ether / 0 deg C to 5 deg C, 1 h, rt, 2 h 2: 81 percent / PBr3, Py / diethyl ether / -15 deg C to -10 deg C, 2 h, rt, 2 d 3: 1.) CuI, 2,2'-bipyridyl, Mg, 2.) TsOH / 1.) THF, HF, 20 deg C, 2 h, 20 deg C, 16 h, reflux, 4 h, 2.) EtOH, rt, 24 h 4: 81 percent / Py / 48 h / Ambient temperature View Scheme

acetic acid T=110°C; 6 h; stereoselective reaction;

1: (Ph)3PPrI With n-butyllithium in tetrahydrofuran; hexanes 1 h; 2: 3-ethoxycarbonylpropionaldehyde in tetrahydrofuran; hexanes T=21°C; 5 h;

1.1: Pearlman's catalist; hydrogen / ethyl acetate / 9 h 2.1: n-butyllithium / tetrahydrofuran; hexanes / 1 h 2.2: 5 h / 21 °C View Scheme