sodium tetrahydroborate in methanol T=-78°C; Fowler reduction; 3 h;

1: 92 percent / CH2Cl2 / 6 h / -78 - 0 °C 2: 77 percent / TMSOTf; BH3 / tetrahydrofuran; CH2Cl2 / 6 h / -78 - 0 °C 3: 99 percent / Jones reagent / acetone / 0 °C 4: LiAlH4; (1R,2S)-(-)-N-methylephedrine; 2-ethylaminopyridine / diethyl ether / 3 h / -78 °C 5: 99 percent / 1N HCl / Heating 6: 70 percent / BH3; H2O2; NaOAc / tetrahydrofuran 7: 95 percent / LiOH View Scheme

sodium tetrahydroborate; trifluoroacetic acid in benzene T=5°C;