sodium cyanoborohydride; acetic acid in tetrahydrofuran T=20°C; 24 h;

1.1: NaH / tetrahydrofuran / 2 h / 0 °C 1.2: 1.27 g / tetrahydrofuran / 8 h / 0 - 20 °C 2.1: t-BuLi / cyclohexane; pentane / 72 h / 20 °C 2.2: I2 / cyclohexane; pentane / 0 - 20 °C 2.3: 40 percent / Jones' reagent / acetone / 0.5 h / 0 °C View Scheme