lithium tri-t-butoxyaluminum hydride in diethyl ether T=-78 - 20°C; 18 h; optical yield given as percent dediastereoselective reaction;

4 A molecular sieve; zinc(II) chloride in tetrahydrofuran T=64°C; 2.5 h;

triethylamine hydrofluoric acid in acetonitrile 72 h; Ambient temperature;

ethanethiol; magnesium bromide in diethyl ether; benzene T=0 - 20°C; SEM deprotection; 11 h;

1.1: 61 percent / n-BuLi / tetrahydrofuran; hexane / 2 h / -78 - 20 °C 2.1: 83 percent / NaBH4 / ethanol / 20 °C 3.1: 90 percent / acetic acid / 2 h / 80 °C 4.1: 99 percent / H2 / 10percent Pd/C / ethyl acetate / 6 h / 2482.38 Torr 5.1: 82 percent / LiAlH4 / diethyl ether / 24 h / Heating 6.1: 100 percent / DMAP / pyridine / 16 h / 20 °C 7.1: 66 percent / PPL / dimethylsulfoxide; aq. phosphate buffer / 2.5 h / 20 °C / pH 7.8 8.1: 100 percent / imidazole / dimethylformamide / 7 h / 20 °C 9.1: 100 percent / K2CO3 / methanol / 1.5 h / 20 °C 10.1: 100 percent / oxalyl chloride; DMSO; Et3N / CH2Cl2 / -78 - -40 °C 11.1: 90 percent / NaOMe / methanol / 20 °C 12.1: 93 percent / i-Pr2NEt / CH2Cl2 / 0 - 20 °C 13.1: 95 percent / 2-methyl-2-butene; NaClO2; NaH2PO4 / 2-methyl-propan-2-ol; H2O / 20 °C 14.1: CDI / tetrahydrofuran / 3 h / 20 °C 14.2: 20 percent / KHMDS / tetrahydrofuran; toluene / 7 h / 0 - 20 °C 15.1: CDI / tetrahydrofuran / 3 h / 20 °C 15.2: 64 percent / n-BuLi / tetrahydrofuran; hexane / 4.5 h / -78 °C 16.1: 85 percent / CuCN / tetrahydrofuran / 3.5 h / 10 °C 17.1: TBAF / tetrahydrofuran / 5 h / 40 - 50 °C 17.2: 62 percent / benzene; CHCl3 / Heating 18.1: 47 percent / LDA; Py*HCl / tetrahydrofuran / -78 - 20 °C 19.1: 81 percent / MgBr2*Et2O; EtSH / diethyl ether; benzene / 11 h / 0 - 20 °C View Scheme

1.1: 83 percent / NaBH4 / ethanol / 20 °C 2.1: 90 percent / acetic acid / 2 h / 80 °C 3.1: 99 percent / H2 / 10percent Pd/C / ethyl acetate / 6 h / 2482.38 Torr 4.1: 82 percent / LiAlH4 / diethyl ether / 24 h / Heating 5.1: 100 percent / DMAP / pyridine / 16 h / 20 °C 6.1: 66 percent / PPL / dimethylsulfoxide; aq. phosphate buffer / 2.5 h / 20 °C / pH 7.8 7.1: 100 percent / imidazole / dimethylformamide / 7 h / 20 °C 8.1: 100 percent / K2CO3 / methanol / 1.5 h / 20 °C 9.1: 100 percent / oxalyl chloride; DMSO; Et3N / CH2Cl2 / -78 - -40 °C 10.1: 90 percent / NaOMe / methanol / 20 °C 11.1: 93 percent / i-Pr2NEt / CH2Cl2 / 0 - 20 °C 12.1: 95 percent / 2-methyl-2-butene; NaClO2; NaH2PO4 / 2-methyl-propan-2-ol; H2O / 20 °C 13.1: CDI / tetrahydrofuran / 3 h / 20 °C 13.2: 20 percent / KHMDS / tetrahydrofuran; toluene / 7 h / 0 - 20 °C 14.1: CDI / tetrahydrofuran / 3 h / 20 °C 14.2: 64 percent / n-BuLi / tetrahydrofuran; hexane / 4.5 h / -78 °C 15.1: 85 percent / CuCN / tetrahydrofuran / 3.5 h / 10 °C 16.1: TBAF / tetrahydrofuran / 5 h / 40 - 50 °C 16.2: 62 percent / benzene; CHCl3 / Heating 17.1: 47 percent / LDA; Py*HCl / tetrahydrofuran / -78 - 20 °C 18.1: 81 percent / MgBr2*Et2O; EtSH / diethyl ether; benzene / 11 h / 0 - 20 °C View Scheme

1.1: 90 percent / acetic acid / 2 h / 80 °C 2.1: 99 percent / H2 / 10percent Pd/C / ethyl acetate / 6 h / 2482.38 Torr 3.1: 82 percent / LiAlH4 / diethyl ether / 24 h / Heating 4.1: 100 percent / DMAP / pyridine / 16 h / 20 °C 5.1: 66 percent / PPL / dimethylsulfoxide; aq. phosphate buffer / 2.5 h / 20 °C / pH 7.8 6.1: 100 percent / imidazole / dimethylformamide / 7 h / 20 °C 7.1: 100 percent / K2CO3 / methanol / 1.5 h / 20 °C 8.1: 100 percent / oxalyl chloride; DMSO; Et3N / CH2Cl2 / -78 - -40 °C 9.1: 90 percent / NaOMe / methanol / 20 °C 10.1: 93 percent / i-Pr2NEt / CH2Cl2 / 0 - 20 °C 11.1: 95 percent / 2-methyl-2-butene; NaClO2; NaH2PO4 / 2-methyl-propan-2-ol; H2O / 20 °C 12.1: CDI / tetrahydrofuran / 3 h / 20 °C 12.2: 20 percent / KHMDS / tetrahydrofuran; toluene / 7 h / 0 - 20 °C 13.1: CDI / tetrahydrofuran / 3 h / 20 °C 13.2: 64 percent / n-BuLi / tetrahydrofuran; hexane / 4.5 h / -78 °C 14.1: 85 percent / CuCN / tetrahydrofuran / 3.5 h / 10 °C 15.1: TBAF / tetrahydrofuran / 5 h / 40 - 50 °C 15.2: 62 percent / benzene; CHCl3 / Heating 16.1: 47 percent / LDA; Py*HCl / tetrahydrofuran / -78 - 20 °C 17.1: 81 percent / MgBr2*Et2O; EtSH / diethyl ether; benzene / 11 h / 0 - 20 °C View Scheme

1: 79 percent / acetonitrile / 29 h / 50 °C 2: 87 percent / AcOH / 13 h / 49 °C 3: 71 percent / H2 / 10percent Pd/C / ethyl acetate / 40 h / 22 °C 4: 80.5 percent / acetic acid; tetrahydrofuran / 3 h / 20 °C 5: 32.1 percent / aq. HCl / dioxane / 51 h / 41 - 43 °C 6: 85 percent / methanol; diethyl ether / 0 - 5 °C 7: 84 percent / LiEt3BH / tetrahydrofuran / 1 h / -78 °C 8: ZnCl2, 4 Angstroem molecular sieves / tetrahydrofuran / 2.5 h / Heating View Scheme

1: 1.) lithium hexamethyldisilazide, 2.) acetic acid / 1.) THF, 0 deg C, 40 min, 2.) THF, -78 deg C, 10 min 2: 79 percent / triethylammonium fluoride / acetonitrile / 72 h / Ambient temperature View Scheme

1: 74 percent / xylene / 36 h / 210 °C 2: 94 percent / lithium tri-tert-butoxyaluminum hydride / tetrahydrofuran / 3.5 h / Ambient temperature 3: 93 percent / 2,6-lutidine / CH2Cl2 / 4 h / 0 °C 4: 1.) lithium hexamethyldisilazide, 2.) acetic acid / 1.) THF, 0 deg C, 40 min, 2.) THF, -78 deg C, 10 min 5: 79 percent / triethylammonium fluoride / acetonitrile / 72 h / Ambient temperature View Scheme