1: 100 percent / H2 / 10percent Pd/C / ethyl acetate; methanol / 4 h 2: 99 percent / LiBH4 / diethyl ether / 15 h / Ambient temperature 3: 87 percent / oxalyl chloride, DMSO / CH2Cl2 / 0.25 h / -60 °C 4: 1) t-BuOK / 1) THF, toluene, 10 min, 2) toluene, 0 deg C, 20 min 5: 1) CH2Cl2, molecular sieves 3A, UV, 0 - 5 deg C 6: 74 percent / 1 M BuOK / tetrahydrofuran; 2-methyl-propan-2-ol / Heating 7: CF3COOH, H2O 8: diethyl phosphorocyanidate, triethylamine / dimethylformamide View Scheme

1: 100 percent / H2 / 10percent Pd/C / ethyl acetate; methanol / 4 h 2: 99 percent / LiBH4 / diethyl ether / 15 h / Ambient temperature 3: 87 percent / oxalyl chloride, DMSO / CH2Cl2 / 0.25 h / -60 °C 4: 1) t-BuOK / 1) THF, toluene, 10 min, 2) toluene, 0 deg C, 20 min 5: 1) CH2Cl2, molecular sieves 3A, UV, 0 - 5 deg C 6: 74 percent / 1 M BuOK / tetrahydrofuran; 2-methyl-propan-2-ol / Heating 7: CF3COOH, H2O View Scheme

1: 39 percent / Me3SiCl / diethyl ether / 3 h / -78 - 20 °C 2: 96 percent / LiBH4 / diethyl ether / 13 h / 20 °C 3: 93 percent / (COCl)2; DMSO / CH2Cl2 / 0.25 h / -60 °C View Scheme