1: LiAlH4 / diethyl ether / 1.) RT, 12 h, 2.) reflux, 1 h 2: p-TsOH*H2O / 3 h / 24 °C 3: 1.) (COCl)2, DMSO, 2.) Et3N / 1.) CH2Cl2, from -50 deg C to -20 deg C, 1.5 h, 2.) CH2Cl2, from -20 deg C to RT, 1 h 4: camphorsulfonic acid / 12 h / 24 °C 5: 1.) O3, 2.) Me2S / 1.) MeOH, CH2Cl2, -78 deg C, 1 h, 2.) MeOH, CH2Cl2, from -78 deg C to RT 6: NaBH4 / ethanol / 0.25 h / 0 °C 7: camphorsulfonic acid / CH2Cl2 / 12 h / 23 °C View Scheme

1: 35.3 g / picric acid / CH2Cl2 / 15 h / Ambient temperature 2: 25.1 percent / LAH / tetrahydrofuran / 15 h / Ambient temperature 3: 91 percent / Dowex 50 W / tetrahydrofuran; H2O / 12 h / 50 °C 4: 60 percent / anh. ZnCl2 / 48 h / Ambient temperature View Scheme