1.1: imidazole / dimethylformamide / 20 °C 2.1: AD-mixα; methanesulfonamide / H2O; 2-methyl-propan-2-ol; CH2Cl2 / 0 °C 3.1: TBAF / tetrahydrofuran / 4 h / 20 °C 4.1: triethyl orthoformate; pyridinium p-toluenesulfonate / 1,2-dichloro-ethane / 5 h / 60 °C 4.2: K2CO3 / methanol; 1,2-dimethoxy-ethane / 20 °C View Scheme

1.1: AD-mixα; methanesulfonamide / H2O; 2-methyl-propan-2-ol; CH2Cl2 / 0 °C 2.1: TBAF / tetrahydrofuran / 4 h / 20 °C 3.1: triethyl orthoformate; pyridinium p-toluenesulfonate / 1,2-dichloro-ethane / 5 h / 60 °C 3.2: K2CO3 / methanol; 1,2-dimethoxy-ethane / 20 °C View Scheme

1.1: TBAF / tetrahydrofuran / 4 h / 20 °C 2.1: triethyl orthoformate; pyridinium p-toluenesulfonate / 1,2-dichloro-ethane / 5 h / 60 °C 2.2: K2CO3 / methanol; 1,2-dimethoxy-ethane / 20 °C View Scheme

1.1: 47.3 percent / silica gel supported H2SO4 / CH2Cl2 / 20 °C 2.1: imidazole / dimethylformamide / 20 °C 3.1: AD-mixα; methanesulfonamide / H2O; 2-methyl-propan-2-ol; CH2Cl2 / 0 °C 4.1: TBAF / tetrahydrofuran / 4 h / 20 °C 5.1: triethyl orthoformate; pyridinium p-toluenesulfonate / 1,2-dichloro-ethane / 5 h / 60 °C 5.2: K2CO3 / methanol; 1,2-dimethoxy-ethane / 20 °C View Scheme

sodium methylate in methanol; dichloromethane 0.166667 h; Ambient temperature; Yield given;

1: NaH, H2O / dimethylformamide / Ambient temperature 2: CH3ONa / methanol; CH2Cl2 / 0.17 h / Ambient temperature View Scheme

1: NaH, H2O / dimethylformamide / Ambient temperature 2: CH3ONa / methanol; CH2Cl2 / 0.17 h / Ambient temperature View Scheme

1: N,N-dimethyl-formamide / 18 h / Reflux 2: diisobutylaluminium hydride / toluene / 3.5 h / -78 °C 3: dichloromethane / 18 h / 20 °C 4: diisobutylaluminium hydride / toluene / 2 h / -78 °C 5: Montmorillonite K-10 / dichloromethane / 5 h / 20 °C 6: N-ethyl-N,N-diisopropylamine / dichloromethane / 18 h / 20 °C 7: AD-mix-α; methanesulfonamide / water; tert-butyl alcohol / 72 h / 0 °C 8: tetrabutyl ammonium fluoride / tetrahydrofuran / 18 h / 20 °C 9: pyridinium p-toluenesulfonate / dichloromethane / 4 h / 60 °C 10: methanol; potassium carbonate / dichloromethane / 18 h / 20 °C View Scheme

1: diisobutylaluminium hydride / toluene / 3.5 h / -78 °C 2: dichloromethane / 18 h / 20 °C 3: diisobutylaluminium hydride / toluene / 2 h / -78 °C 4: Montmorillonite K-10 / dichloromethane / 5 h / 20 °C 5: N-ethyl-N,N-diisopropylamine / dichloromethane / 18 h / 20 °C 6: AD-mix-α; methanesulfonamide / water; tert-butyl alcohol / 72 h / 0 °C 7: tetrabutyl ammonium fluoride / tetrahydrofuran / 18 h / 20 °C 8: pyridinium p-toluenesulfonate / dichloromethane / 4 h / 60 °C 9: methanol; potassium carbonate / dichloromethane / 18 h / 20 °C View Scheme

1: 90 percent / Dess-Martin periodinane; H2O / CH2Cl2 / 20 °C 2: 81 percent / L-Selectride; LiBr / tetrahydrofuran / -78 °C 3: 52 percent / DDQ / CH2Cl2 / 20 °C 4: 53 percent / TiCl4 / CH2Cl2; tetrahydrofuran / 20 °C 5: H2 / 20 percent Pd(OH)2/C / tetrahydrofuran; methanol; H2O / 750.06 Torr View Scheme