1: tetrahydrofuran; diethyl ether / -78 °C 2: 86 percent / pyridinium chlorochromate, sodium acetate / CH2Cl2 / 1.5 h View Scheme

1: tetrahydrofuran; diethyl ether / -78 °C 2: 86 percent / pyridinium chlorochromate, sodium acetate / CH2Cl2 / 1.5 h 3: 52 percent / p-toluenesulfonic acid / 7 h / Heating 4: 1.) n-butyllithium / 1.) THF, hexane, -78 deg C 2.) THF, hexane, 0 deg C View Scheme

1: tetrahydrofuran; diethyl ether / -78 °C 2: 86 percent / pyridinium chlorochromate, sodium acetate / CH2Cl2 / 1.5 h 3: 52 percent / p-toluenesulfonic acid / 7 h / Heating 4: 1.) n-butyllithium / 1.) THF, hexane, -78 deg C 2.) THF, hexane, 0 deg C 5: 54 percent / P(C6H5)3*Br2, collidine / CH2Cl2 / 0.25 h / 0 °C View Scheme

1: tetrahydrofuran; diethyl ether / -78 °C 2: 86 percent / pyridinium chlorochromate, sodium acetate / CH2Cl2 / 1.5 h 3: 52 percent / p-toluenesulfonic acid / 7 h / Heating 4: 1.) n-butyllithium / 1.) THF, hexane, -78 deg C 2.) THF, hexane, 0 deg C 5: 1.) n-butyllithium, HMPA / 1.)THF, hexane, -78 degC to 0 degC 2.) 45-50 degC, 2 h 6: 63 percent / 5percent HCl / tetrahydrofuran; H2O / 2 h / 50 °C View Scheme

1: tetrahydrofuran; diethyl ether / -78 °C 2: 86 percent / pyridinium chlorochromate, sodium acetate / CH2Cl2 / 1.5 h 3: 52 percent / p-toluenesulfonic acid / 7 h / Heating View Scheme

1: tetrahydrofuran; diethyl ether / -78 °C 2: 86 percent / pyridinium chlorochromate, sodium acetate / CH2Cl2 / 1.5 h 3: 52 percent / p-toluenesulfonic acid / 7 h / Heating 4: 1.) n-butyllithium, 2.) iodine / 1.) THF, hexane, -78 deg C to 0 deg C, 2.) THF, hexane, 30 min 5: tetrahydrofuran; hexane / 0.5 h / -78 °C View Scheme

1: 71 percent / diethyl ether / 2 h / Ambient temperature 2: 74 percent / lithium amide, ammonia / tetrahydrofuran / 4 h / Ambient temperature 3: 1) CrO3, pyridine / 1) CH2Cl2, 15-20 deg C, 0.5 h; 2) 15 min 4: 5.05 g / triethylamine, H2 / palladium/calcium carbonate / tetrahydrofuran View Scheme

1: 71 percent / diethyl ether / 2 h / Ambient temperature 2: 74 percent / lithium amide, ammonia / tetrahydrofuran / 4 h / Ambient temperature 3: 1) CrO3, pyridine / 1) CH2Cl2, 15-20 deg C, 0.5 h; 2) 15 min 4: 5.05 g / triethylamine, H2 / palladium/calcium carbonate / tetrahydrofuran 5: Jones reagent / acetone / 2 h / Ambient temperature View Scheme

1,8-diazabicyclo[5.4.0]undec-7-ene; lithium bromide in tetrahydrofuran T=20°C; Horner-Wadsworth-Emmons reaction;

in dichloromethane T=-78°C; Yield given;