hydrogenchloride in tetrahydrofuran; water T=20°C; 48 h;

potassium carbonate in methanol; water T=0°C;

1: Et3N / tetrahydrofuran / 3 h / 20 °C 2: 16.8 mg / 4-dimethylaminopyridine / toluene / 8 h / Heating 3: 77 percent / TBAF / tetrahydrofuran / 4 h / 0 °C View Scheme

sodium tetrahydroborate in methanol T=-78°C;

titanium tetrachloride in dichloromethane T=0°C; 2 h;

1: 40.6 mg / aq. NaOH / tetrahydrofuran; methanol / 1 h / 60 °C 2: Et3N / tetrahydrofuran / 3 h / 20 °C 3: 16.8 mg / 4-dimethylaminopyridine / toluene / 8 h / Heating 4: 77 percent / TBAF / tetrahydrofuran / 4 h / 0 °C View Scheme

1.1: DIAD; PPh3 / tetrahydrofuran 2.1: Oxone; H2O / methanol / 60 °C 3.1: potassium hexamethyldisilylazide / 1,2-dimethoxy-ethane / 1 h / -78 °C 3.2: 1,2-dimethoxy-ethane / -78 - 20 °C 4.1: CAN; H2O / acetone 5.1: aq. NaOH / tetrahydrofuran; methanol 6.1: 61 percent / MsCl; Et3N; 2,4,6-trichlorobenzoyl chloride / 4-DMAP / toluene / Heating 7.1: 77 percent / TBAF / tetrahydrofuran / 20 °C View Scheme

1.1: NaBH4; NiCl2 / methanol / 0 °C 2.1: DIBAL-H / tetrahydrofuran 3.1: DIAD; PPh3 / tetrahydrofuran 4.1: Oxone; H2O / methanol / 60 °C 5.1: potassium hexamethyldisilylazide / 1,2-dimethoxy-ethane / 1 h / -78 °C 5.2: 1,2-dimethoxy-ethane / -78 - 20 °C 6.1: CAN; H2O / acetone 7.1: aq. NaOH / tetrahydrofuran; methanol 8.1: 61 percent / MsCl; Et3N; 2,4,6-trichlorobenzoyl chloride / 4-DMAP / toluene / Heating 9.1: 77 percent / TBAF / tetrahydrofuran / 20 °C View Scheme

1.1: n-butyllitium / tetrahydrofuran; hexane; hexamethylphosphoric acid triamide / 1 h / -78 °C 1.2: 73 percent / tetrahydrofuran; hexane; hexamethylphosphoric acid triamide / 4 h / -78 °C 2.1: (EtO)3SiH / Cp*Ru(CH3CN)3PF6 / CH2Cl2 / 3 h / 20 °C 2.2: 92 percent / cesium fluoride; ethanol / CH2Cl2 / 12 h / 20 °C 3.1: pyridine / CH2Cl2 4.1: DIBAL-H / tetrahydrofuran / -78 °C 5.1: potassium hexamethyldisilylazide / 1,2-dimethoxy-ethane / 1 h / -78 °C 5.2: 1,2-dimethoxy-ethane / -78 - 20 °C 6.1: CAN; H2O / acetone 7.1: aq. NaOH / tetrahydrofuran; methanol 8.1: 61 percent / MsCl; Et3N; 2,4,6-trichlorobenzoyl chloride / 4-DMAP / toluene / Heating 9.1: 77 percent / TBAF / tetrahydrofuran / 20 °C View Scheme

1.1: DIBAL-H; BHT / toluene 2.1: pyridine 3.1: (i-Pr)MgCl / tetrahydrofuran / -10 °C 4.1: DBU / CH2Cl2 5.1: n-butyllitium / tetrahydrofuran; hexane; hexamethylphosphoric acid triamide / 1 h / -78 °C 5.2: 73 percent / tetrahydrofuran; hexane; hexamethylphosphoric acid triamide / 4 h / -78 °C 6.1: (EtO)3SiH / Cp*Ru(CH3CN)3PF6 / CH2Cl2 / 3 h / 20 °C 6.2: 92 percent / cesium fluoride; ethanol / CH2Cl2 / 12 h / 20 °C 7.1: pyridine / CH2Cl2 8.1: DIBAL-H / tetrahydrofuran / -78 °C 9.1: potassium hexamethyldisilylazide / 1,2-dimethoxy-ethane / 1 h / -78 °C 9.2: 1,2-dimethoxy-ethane / -78 - 20 °C 10.1: CAN; H2O / acetone 11.1: aq. NaOH / tetrahydrofuran; methanol 12.1: 61 percent / MsCl; Et3N; 2,4,6-trichlorobenzoyl chloride / 4-DMAP / toluene / Heating 13.1: 77 percent / TBAF / tetrahydrofuran / 20 °C View Scheme