1.1: BH3 / tetrahydrofuran / 1.5 h / 0 - 20 °C 1.2: 63 percent / hydrogen peroxide; NaOH / tetrahydrofuran; H2O / 1.5 h / 0 - 20 °C 2.1: 94 percent / pyridine / CH2Cl2 / 20 °C 3.1: 77 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 2 h / 55 - 60 °C 4.1: 100 percent / aq. NaOH / tetrahydrofuran / 1 h / 80 °C 5.1: 50 percent / trifluoroacetic acid / CH2Cl2 View Scheme