1: 0.1 M aq. p-toluenesulfonic acid / tetrahydrofuran / 0.3 h / Heating 2: 1.) NaN(SiMe3)2 / 1.) THF, toluene, RT, 1 h, 2.) from -100 to 0 deg C, 4 h 3: 0.1 M aq. p-toluenesulfonic acid / tetrahydrofuran / 0.3 h / Heating 4: 1.) NaN(SiMe3)2 / 1.) THF, HMPA, RT, 2 h, 2.) from -100 to 0 deg C, 4 h View Scheme

1: p-TsOH / H2O; tetrahydrofuran / 0.17 h / Heating 2: LiAlH4 / tetrahydrofuran / 2.5 h / -90 to -20 deg C 3: 90 percent / PPh3Br2, pyridine / acetonitrile / 1 h / -7 to RT 4: 100 percent / acetonitrile / 48 h / Heating 5: 86 percent / NaN(SiMe3)2 / tetrahydrofuran / 12 h / -100 deg C to RT 6: 93 percent / DIBAH / CH2Cl2 / 1 h / -90 °C 7: 81 percent / EtAlCl2 / diethyl ether; hexane / 2.5 h / -40 to -20 deg C 8: 77 percent / 40percent aq. HF / acetonitrile / 12 h / 0 deg C to RT 9: 70 percent / Bu4NF / tetrahydrofuran / 0.25 h / -90 °C 10: 50 percent / PPh3, diethyl azodicarboxylate / tetrahydrofuran / 1.5 h / 0 deg C to RT View Scheme

1: p-TsOH / tetrahydrofuran; H2O / 0.25 h / Heating 2: LiAlH4 / tetrahydrofuran / -90 - -20 °C View Scheme

toluene-4-sulfonic acid in tetrahydrofuran 0.333333 h; Heating;

1: 0.1 M aq. p-toluenesulfonic acid / tetrahydrofuran / 0.3 h / Heating 2: 1.) NaN(SiMe3)2 / 1.) THF, toluene, RT, 1 h, 2.) from -100 to 0 deg C, 4 h 3: 0.1 M aq. p-toluenesulfonic acid / tetrahydrofuran / 0.3 h / Heating 4: 1.) NaN(SiMe3)2 / 1.) THF, HMPA, RT, 2 h, 2.) from -100 to 0 deg C, 4 h 5: diethyl ether / 0 °C View Scheme

1: p-TsOH / tetrahydrofuran; H2O / 0.25 h / Heating 2: LiAlH4 / tetrahydrofuran / -90 - -20 °C 3: 91 percent / Ph3P*Br2, pyridine / acetonitrile / 1.) -7 deg C, 10 min, 2.) r.t., 1 h View Scheme

Multi-step reaction with 9 steps 1: p-TsOH / H2O; tetrahydrofuran / 0.17 h / Heating2: LiAlH4 / tetrahydrofuran / 2.5 h / -90 to -20 deg C3: 90 percent / PPh3Br2, pyridine / acetonitrile / 1 h / -7 to RT4: 100 percent / acetonitrile / 48 h / Heating5: 86 percent / NaN(SiMe3)2 / tetrahydrofuran / 12 h / -100 deg C to RT6: 93 percent / DIBAH / CH2Cl2 / 1 h / -90 °C7: 81 percent / EtAlCl2 / diethyl ether; hexane / 2.5 h / -40 to -20 deg C8: 77 percent / 40percent aq. HF / acetonitrile / 12 h / 0 deg C to RT9: 70 percent / Bu4NF / tetrahydrofuran / 0.25 h / -90 °C