1: 100 percent / NaBH4 / methanol / 2 h / Ambient temperature 2: 94 percent / Na, liq. NH3 / tetrahydrofuran / 0.5 h / -50 - -45 °C 3: 82 percent / Jones' reagent / acetone / 0.25 h / -15 - -10 °C 4: 72 percent / n-C4H9Br, Li / tetrahydrofuran; diethyl ether / 1.) -10 deg C, 2 h; -5 deg C, 3 h, 2.) -5 deg C, 3 h View Scheme

1: 100 percent / NaBH4 / methanol / 2 h / Ambient temperature 2: 94 percent / Na, liq. NH3 / tetrahydrofuran / 0.5 h / -50 - -45 °C 3: 82 percent / Jones' reagent / acetone / 0.25 h / -15 - -10 °C View Scheme