sodium tetrahydroborate; nickel dichloride in methanol Ambient temperature;

1: 83 percent / NaBH4, nickel(II) chloride*6 H2O / methanol / Ambient temperature 2: 92 percent / formic acid / 0 °C 3: 95 percent / borane-THF / tetrahydrofuran / Ambient temperature 4: 78 percent / nitrosonium tetrafluoroborate, Et3N / diethyl ether / Ambient temperature 5: 62 percent / TBAF / tetrahydrofuran / 0 °C View Scheme