sodium tetrahydroborate in ethanol 3 h;

1: 60 percent / NaBH4 / ethanol / 3 h 2: 60 percent / PBr3 / diethyl ether; pyridine / 2 h / Heating 3: 1.) activated Mg; 2.) Li2CuCl4 / 1.)THF, N2 2.) THF, -10 deg C, 5.5 h 4: 92 percent / acetic acid; pyridine / 13 h / 0 °C View Scheme

1: 60 percent / NaBH4 / ethanol / 3 h 2: 60 percent / PBr3 / diethyl ether; pyridine / 2 h / Heating 3: 1.) activated Mg; 2.) Li2CuCl4 / 1.)THF, N2 2.) THF, -10 deg C, 5.5 h 4: 52 percent / PTS / methanol / 6 h / 55 °C 5: 60 percent / PCC / CH2Cl2 / 2 h View Scheme

1: 60 percent / NaBH4 / ethanol / 3 h 2: 60 percent / PBr3 / diethyl ether; pyridine / 2 h / Heating 3: 1.) activated Mg; 2.) Li2CuCl4 / 1.)THF, N2 2.) THF, -10 deg C, 5.5 h 4: 52 percent / PTS / methanol / 6 h / 55 °C View Scheme

1: 60 percent / NaBH4 / ethanol / 3 h 2: 60 percent / PBr3 / diethyl ether; pyridine / 2 h / Heating 3: 1.) activated Mg; 2.) Li2CuCl4 / 1.)THF, N2 2.) THF, -10 deg C, 5.5 h 4: 52 percent / PTS / methanol / 6 h / 55 °C View Scheme

1: 60 percent / NaBH4 / ethanol / 3 h 2: 60 percent / PBr3 / diethyl ether; pyridine / 2 h / Heating 3: 1.) activated Mg; 2.) Li2CuCl4 / 1.)THF, N2 2.) THF, -10 deg C, 5.5 h 4: 89 percent / acetic acid; pyridine / 13 h / 0 °C View Scheme

1: 60 percent / NaBH4 / ethanol / 3 h 2: 60 percent / PBr3 / diethyl ether; pyridine / 2 h / Heating View Scheme